Wikipedija mtwiki https://mt.wikipedia.org/wiki/Il-Pa%C4%A1na_prin%C4%8Bipali MediaWiki 1.47.0-wmf.2 first-letter Medja Speċjali Diskussjoni Utent Diskussjoni utent Wikipedija Diskussjoni Wikipedija Stampa Diskussjoni stampa MediaWiki Diskussjoni MediaWiki Mudell Diskussjoni mudell Għajnuna Diskussjoni għajnuna Kategorija Diskussjoni kategorija Portal Diskussjoni portal TimedText TimedText talk Module Module talk Event Event talk 0 23901 330134 328113 2026-05-18T10:26:38Z -wuppertaler 25886 changed one image (higher resolution) 330134 wikitext text/x-wiki {{stub|ġeografija}} {{infobox city}} '''Vaduz''' hi l-belt kapitali tal-[[Liechtenstein]]. Il-belt għandha popolazzjoni ta' 5,407 ruħ (sal-2016). == Ġeografija == Il-muniċipalità ta' Vaduz tkopri erja ta' 17.3 km², maqsuma f'territorju ewlieni u sitt enklavi. Li tinsab fuq ix-xatt tal-lemin tar-Renu, il-parti ċentrali fiha ż-żona urbana tal-kapitali, kif ukoll ir-raħal ta' Ebenholz. Żewġ porzjonijiet tat-territorju huma magħluqa fil-muniċipalità ta' Schaan fit-tramuntana, tnejn oħra fil-muniċipalità ta' Planken fil-grigal, u l-aħħar tnejn jinsabu f'żona muntanjuża fix-xlokk tal-pajjiż<ref>{{Ċita web|url=http://www.weatherbase.com/?msu=go|titlu=Travel Weather Averages (Weatherbase)|sit=Weatherbase|data-aċċess=2025-06-10|arkivju-url=https://web.archive.org/web/20230721235648/http://www.weatherbase.com/?msu=go|arkivju-data=2023-07-21|url-status=dead}}</ref>. [[Stampa:Liechtenstein asv2022-10 img22 Vaduz Schloss.jpg|nofs|daqsminuri|Il-Kastell ta' Vaduz, li jħares fuq il-belt kapitali tal-istess isem]] == Storja == Vaduz jissemma f'manuskritti storiċi tas-seklu 12 bħala Faduzes. Fl-1322 jissemma l-kastell, li ġie mħarrek mill-Iżvizzeri fl-1499 matul il-Gwerra Swabiana. Ir-raħal kollu nqered ukoll. Fis-seklu 17 il-familja Liechtenstein kienet qed tfittex siġġu fid-dieta Imperjali, ir-''Reichstag''. Peress li ma kellhom l-ebda territorju li kien direttament taħt it-tron Imperjali, ma setgħux jissodisfaw ir-rekwiżit primarju biex jikkwalifikaw<ref>{{Ċita web|url=https://pages.uoregon.edu/dluebke/Reformations441/441ImperialPrimer.htm|titlu=441ImperialPrimer|sit=pages.uoregon.edu|data-aċċess=2025-06-10}}</ref>. Il-familja xtaqet il-poter miżjud li kien iġib miegħu siġġu fil-gvern Imperjali, u għalhekk fittxet li takkwista artijiet li kienu jkunu ''reichsunmittelbar'', jew miżmuma direttament mill-Imperatur Ruman Imqaddes innifsu, mingħajr ebda patrunaġġ feudali intermedju. Wara xi żmien, il-familja setgħet tirranġa x-xiri tal-''Herrschaft'' ("Sinjur") ċkejken ta' ''Schellenberg'' u l-konteja ta' Vaduz (fl-1699 u l-1712, rispettivament) mill-''Hohenems''. Iż-żgħar Schellenberg u Vaduz kellhom eżattament l-istatus politiku meħtieġ: l-ebda sid feudali ħlief l-Imperatur. B'hekk, fit-23 ta' Jannar 1719, wara li x-xiri kien sar kif suppost, Karlu VI, Imperatur Ruman Imqaddes, iddikjara li Vaduz u Schellenberg ingħaqdu, u ġew elevati għad-dinjità ta' Fürstentum (prinċipalità) bl-isem "Liechtenstein" ad unur "il-qaddej veru tiegħu, Anton Florian tal-Liechtenstein". Huwa f'din id-data li l-Liechtenstein sar stat membru sovran tal-Imperu Ruman Imqaddes. Bħala xhieda tal-konvenjenza politika pura tax-xiri, il-Prinċpijiet tal-Liechtenstein ma poġġewx saqajhom fil-prinċipat il-ġdid tagħhom għal aktar minn 120 sena. == Politika == [[Stampa:Landtagsgebäude des Fürstentums Liechtenstein.jpg|nofs|daqsminuri|[[Parlament tal-Liechtenstein]] ]] Vaduz hija d-dar tal-kwartieri ġenerali tal-istituzzjonijiet ewlenin tal-pajjiż, il-Gvern u l-Parlament. == Ekonomija u trasport == Vaduz hija waħda mill-ftit bliet kapitali fid-dinja li m'għandhiex ajruport. L-eqreb ajruport ewlieni huwa l-Ajruport ta' Zurich, u l-eqreb ajruport minuri huwa l-Ajruport ta' St. Gallen-Altenrhein. L-Ajruport ta' Friedrichshafen jipprovdi wkoll aċċess għal Vaduz. Bil-karozza, Vaduz hija aċċessibbli direttament permezz tal-awtostrada A13 fl-Iżvizzera, jew permezz tal-awtostrada A14 fl-Awstrija. Vaduz hija konnessa mal-Iżvizzera fuq ix-xmara Rhine permezz tal-pont pedonali Vaduz-Sevelen, jew il-pont Werdenberger-Binnenkanal għal vetturi bil-mutur, li nfetaħ fl-1975. Ix-xarabanks jistgħu jittieħdu minn Buchs, St. Gallen, Sevelen u Feldkirch lejn Vaduz. Dawn ix-xarabanks tipikament jiġru kull 20 sa 40 minuta u huma operati minn Liechtenstein Bus. L-istazzjon tal-ferrovija ta' Schaan-Vaduz, li jinsab f'Schaan, huwa l-eqreb stazzjon tal-ferrovija għal Vaduz. L-istazzjon jinsab fuq il-linja ferrovjarja Feldkirch–Buchs, l-unika linja ferrovjarja tal-Liechtenstein, u huwa servut mill-S2 tal-Vorarlberg S-Bahn, li hija operata mill-Ferroviji Federali Awstrijaċi (ÖBB). Infetaħ fl-24 ta' Ottubru 1872 bi ftehim mal-Awstrija-Ungerija u l-Iżvizzera. Saru tentattivi biex in-netwerk ferrovjarju jiġi estiż biex jikkonnettja ma' Vaduz, għalkemm dawn ma rnexxewx<ref>{{Ċita web|url=https://historisches-lexikon.li/Eisenbahn?marker=bahn|titlu=Eisenbahn – Historisches Lexikon|sit=historisches-lexikon.li|lingwa=de|data-aċċess=2025-06-10}}</ref>. == Punti ta' interess ewlenin == Il-Kastell ta’ Vaduz huwa d-dar tal-prinċep renjanti tal-Liechtenstein u l-familja prinċipessa tal-Liechtenstein. Il-kastell huwa viżibbli minn kważi kull post f’Vaduz, billi jinsab fuq għolja wieqfa f’nofs ir-raħal. Il-Katidral ta’ San Florin, id-Dar tal-Gvern u s-Sala tal-Villaġġ juru d-diversi stili u perjodi ta’ arkitettura fir-raħal. [[Stampa:Liechtenstein asv2022-10 img21 Vaduz Kathedrale StFlorin.jpg|nofs|daqsminuri|Katidral ta’ San Florin]] == Referenzi == {{Lista ta' kapitali Ewropej skont ir-reġjun}} [[Category:Bliet kapitali fl-Ewropa]] hej526ytp9u2xw681zvphgjn8win5ii 2 25623 330122 330092 2026-05-17T19:16:43Z Trigcly 17859 aġġornament 330122 wikitext text/x-wiki == '''Artikli ġodda (2001)''' == === <u>'''A'''</u> === * [[Aapravasi Ghat]] * [[Aasivissuit-Nipisat: Territorju tal-Kaċċa tal-Inuit bejn is-Silġ u l-Baħar]] * [[Abbazija ta' Corvey]] * [[Abbazija ta' Fontenay]] * [[Abbazija ta' Lorsch]] * [[Abbazija ta' Pannonhalma]] *[[Abbazija ta' Saint-Savin-sur-Gartempe]] *[[Abbazija ta' Sankt Gallen]] *[[Abbazija ta’ Vézelay|Abbazija ta' Vezelay]] *[[Abu al-Fida]] *[[Abu Mena]] *[[Abu Simbel]] *[[Ċentru Storiku ta' Acre|Acre]] *[[Afag Bashirgyzy]] *[[Aflaj tal-Oman]] *[[Afrodisja]] *[[Agadez]] *[[Agostino Carracci]] *[[Agostino Matrenza]] *[[Ahwar tan-Nofsinhar tal-Iraq]] *[[Aigai]] *[[Aït Benhaddou]] *[[Akkwedott ta' Padre Tembleque]] *[[Akkwedott ta' Pontcysyllte]] *[[Akshata Murthy]] *[[Aksum]] *[[Al Qal'a ta' Beni Hammad]] *[[Al Zubarah]] *[[Al-Maghtas]] *[[Alatyr]] *[[Albéric Magnard]] *[[Alberobello]] *[[Albi]] *[[Alcalá de Henares]] *[[Alcide d'Orbigny]] *[[Aleksandr Yakovlevich Khinchin]] *[[Alenush Terian]] *[[Aleppo]] *[[Alessandro Scarlatti]] *[[Alessandro Volta]] *[[Alexander Pushkin]] *[[Alexander Wolszczan]] *[[Aleksandra Smiljanić]] *[[Alfred Hermann Fried]] *[[Alfred Nobel]] *[[Alfredo Casella]] *[[Alois Dryák]] *[[Alto Douro]] *[[Amazigh Marokkin Standard]] *[[Ambohimanga]] *[[Ambra Sabatini]] *[[Amerigo Vespucci]] *[[Amerigo Vespucci (vapur għoli)|''Amerigo Vespucci'' (vapur għoli)]] * [[L-Amerika t'Isfel|Amerka t’Isfel]] * [[L-Amerika ta' Fuq|Amerka ta’ Fuq]] *[[Amilcare Ponchielli]] *[[Anastasia Golovina]] *[[Anders Jonas Ångström]] *[[André Citroën]] *[[André Weil]] *[[Anfibju]] *[[Anfiteatru ta' El Jem]] *[[Angelina Mango]] * [[Angkor Wat]] * [[Angra do Heroísmo]] * [[Ani]] * [[Anjar]] * [[Anna Brigadere]] * [[Anna Kyriakou]] *[[Anna Seghers]] *[[Anna Sychravová]] *[[Anne-Sophie Mutter]] *[[Anse aux Meadows]] * [[Antartika]] * [[Anticosti]] * [[Antigua Guatemala]] *[[Antoine de Jussieu]] *[[Antoine de Saint-Exupéry]] *[[Antoinette Miggiani]] *[[Anton Diabelli]] *[[Anuradhapura]] *[[Aplogruppi Y-DNA fit-tribujiet tal-Każakistan]] *[[Aporofobija]] *[[Aquileia]] *[[Arċipelagu ta' Bijagós]] *[[Arċipelagu ta' Revillagigedo]] *[[Arċipelagu ta' Vega]] *[[Arena Tettonika Żvizzera ta' Sardona]] *[[Arequipa]] *[[Arġentier]] *[[Arġentier (tad-deheb)]] *[[Ark Ġeodetiku ta’ Struve|Ark Ġeodetiku ta' Struve]] *[[Arkata Trijonfali ta' Orange]] *[[Arkeoloġija]] *[[Arkitett]] *[[Arkitettura Mudéjar ta' Aragona]] *[[Arkitettura tas-Seklu 20 ta' Frank Lloyd Wright]] *[[Arles]] *[[Armata tat-Terrakotta]] *[[Arslantepe]] *[[Art tal-Inċens]] *[[Arthur Schnitzler]] *[[Arti Paleolitika fl-Għerien tat-Tramuntana ta' Spanja]] *[[Artiġjan]] *[[Artijiet Għoljin Ċentrali tas-Sri Lanka]] *[[As-Salt]] *[[Asmara]] * [[Assisi]] * [[Assi Ċentrali ta' Beijing]] * [[Assur]] * [[Astrofiżika]] *[[Asuman Baytop]] *[[Athos]] *[[Attrazzjonijiet Ewlenin tar-Renju Antik ta' Saba f'Marib]] *[[Auschwitz]] *[[Austin Camilleri]] *[[Ávila]] *[[Avukat]] === '''<u>B</u>''' === * [[Baalbek]] * [[Babilonja]] * [[Baċir tal-Lag ta' Uvs]] * [[Baċir tax-Xogħol fil-Minjieri ta' Nord-Pas de Calais]] * [[Baeza]] * [[Bagan]] * [[Baħar l-Abjad]] * [[Baħar l-Iswed]] *[[Baħar ta' Wadden]] *[[Baħar tar-Ramel tan-Namibja]] *[[Bajja ta' Dungonab]] *[[Bajja ta' Ha Long]] *[[Bajja ta' Tallinn]] *[[Bajja tal-Klieb il-Baħar]] *[[Bajjad]] *[[Baleron]] *[[Bamberg]] *[[Ban Chiang]] *[[Banská Štiavnica]] *[[Barbier]] *[[Bardejov]] *[[Barokk]] *[[Bartolomé de Escobedo]] *[[Bath, Somerset]] *[[Batlejka]] *[[Battaljun Mediku tal-Ospedalieri]] *[[Battir]] *[[Bauhaus u s-Siti tal-Moviment f'Weimar, f'Dessau u f'Bernau]] *[[Baxkortostan]] *[[Bażi tad-Data tal-Osservazzjoni tal-Kometi]] *[[Bażilika Ewfrasjana ta’ Poreč|Bażilika Ewfrasjana ta' Poreč]] *[[Bażilika ta' San Eġidju]] *[[Beatriz Carrillo]] *[[Beemster]] *[[Béguinage]] *[[Belintersat-1]] *[[BelKA]] *[[Belt Bajda ta' Tel Aviv – il-Moviment Modern]] *[[Belt Kolonjali ta' Santo Domingo]] *[[Belt Projbita]] *[[Belt Storika ta' Ahmadabad]] *[[Belt Storika tal-Kajr]] *[[Belt Storika tal-Moskej ta' Bagerhat]] *[[Belt ta' Guanajuato]] *[[Belt ta' New York]] *[[Belt ta' Vicenza u l-Vilel ta' Palladio fil-Veneto|Belt ta' Viċenza u l-Vilel ta' Palladio fil-Veneto]] *[[Belt Universitarja ta' Caracas]] *[[Bennej]] *[[Berġa tal-Italja, il-Belt Valletta]] *[[Berġa tal-Italja, il-Birgu]] *[[Bergpark Wilhelmshöhe]] *[[Bernard Grech]] *[[Betlem]] *[[Betti Alver]] *[[Burkhan Khaldun]] *[[Bidwi]] *[[Bieb il-Belt]] *[[Binjiet Gotiċi Vittorjani u tal-Art Deco ta' Mumbai]] *[[Binjiet Tradizzjonali tal-Asante]] *[[Blat Imkenni ta' Bhimbetka]] *[[Bliet Antiki tal-Pyu]] *[[Bliet Kapitali u Oqbra tar-Renju Antik ta' Koguryo]] *[[Bliet Storiċi tal-Istrett ta' Malakka]] *[[Bobby Charlton]] *[[Bolgar]] *[[Bordeaux]] *[[Borobudur]] *[[Borża ta' Malta]] *[[Bosra]] *[[Bridgetown]] *[[Brook Taylor]] *[[Brú na Bóinne]] *[[Bruno Pizzul]] *[[Bryggen]] *[[Bucha]] *[[Buddha Ġgantesk ta' Leshan]] *[[Bugeddum Armen]] *[[Bukhara]] *[[Burt Bacharach]] *[[Buskett]] *[[Butrint]] *[[Byblos]] === '''<u>Ċ/C</u>''' === * [[Cáceres (Spanja)]] * [[Calakmul]] * [[Camagüey]] * [[Camino Real de Tierra Adentro]] * [[Campeche]] * [[Canal du Midi]] * [[Canaletto]] * [[Caral]] * [[Carcassonne]] *[[Carl Bosch]] *[[Carl David Anderson]] *[[Carl Linnaeus]] *[[Carla Fracci]] *[[Carlo Collodi]] *[[Caroline Mikkelsen]] *[[Casco Viejo, il-Panama]] *[[Castel del Monte, Puglia]] *[[Çatalhöyük]] *[[Causses u Cévennes]] *[[Ċellola]] *[[Ċensu Apap]] *[[Ċentru Kulturali ta' Heydar Aliyev]] *[[Ċentru Storiku ta' Lijiang]] *[[Ċentru Storiku ta' Macao]] *[[Ċentru Storiku ta' Rauma]] *[[Ċentru Storiku ta' Salvador de Bahia]] *[[Český Krumlov]] *[[Ċetta Chevalier]] *[[Chaîne des Puys]] *[[Chakapuli]] *[[Chan Chan]] *[[Changdeokgung]] *[[Chankillo]] *[[Charles Jean de la Vallée-Poussin]] *[[Charles-Amédée-Philippe van Loo]] *[[Charles Nicolle]] *[[Charles Richter]] *[[Charles Xuereb]] *[[Charlie Watts]] *[[Chavín]] *[[Choeung Ek]] *[[Chersonesus Tawrika]] *[[Chichén Itzá]] *[[Chilehaus]] *[[Choirokoitia]] *[[Christiansfeld]] *[[Christopher Polhem]] *[[Cidade Velha]] *[[Cienfuegos]] *[[Ċikli ta' affreski tas-seklu 14 ta' Padova]] *[[Cinque Terre]] *[[Ċirkewwa]] *[[Ċittadella Imperjali ta' Thăng Long]] *[[Ċittadella ta' Erbil]] *[[Ċittadella tad-Dinastija Hồ]] *[[Claude Joseph Rouget de Lisle]] *[[Climats u Terroirs ta' Bourgogne]] *[[Colonia del Sacramento]] *[[Copan]] *[[Córdoba, Spanja]] *[[Coro]] *[[Crespi d'Adda]] *[[Ċrieki tal-Ġebel tas-Senegambja]] *[[Cristofano Allori]] *[[Cuenca, l-Ekwador]] *[[Cuenca (Spanja)]] *[[Cueva de las Manos]] *[[Cumalıkızık]] *[[Curzio Maltese]] *[[Cusco]] *[[Cynthia Turner]] *[[Cyrene]] === '''<u>D</u>''' === * [[Daiga Mieriņa]] * [[Damasku]] * [[Daniel Gabriel Fahrenheit]] * [[Danxia]] *[[Dar ta’ Rietveld Schröder|Dar ta' Rietveld Schröder]] *[[Dar tal-Kimeri]] *[[Dar tat-Twelid ta' Martin Luteru]] *[[Dar u Studjo ta' Luis Barragán]] *[[Delos]] *[[Delphi]] *[[Delta ta' Saloum]] *[[Delta ta' Okavango]] *[[Delta tad-Danubju]] *[[Delta tax-xmara Kızılırmak]] *[[Dengfeng]] *[[Dentist]] *[[Denys Shmyhal]] *[[Déodat Gratet de Dolomieu]] *[[Deżert ta' Badain Jaran]] *[[Deżert ta' Lut]] *[[Deżerta tal-isfarġel]] *[[Dholavira]] *[[Diamantina]] *[[Diana, Prinċipessa ta' Wales]] *[[Diaolou]] *[[Diga ta' Karakaya]] *[[Dikjarazzjoni tal-Indipendenza tal-Ukrajna]] *[[Dimitrana Ivanova]] *[[Distrett ta' At-Turaif]] *[[Diy-Gid-Biy]] *[[Dizzjunarju]] *[[Djalett]] *[[Djar Ewlenin ta' Victor Horta fi Brussell]] *[[Djémila]] *[[Djerba]] *[[DNA]] *[[Dolċier]] *[[Dolmen ta' Menga]] *[[Dolmen ta' Viera]] *[[Dolomiti]] *[[Domenico Allegri]] *[[Domenico Scarlatti]] *[[Domowina]] *[[Domus de Janas]] *[[Domus Rumana]] *[[Donatello]] *[[Dougga]] *[[Draginja Vuksanović-Stanković]] *[[Dubrovnik]] *[[Durmitor]] * [[Dwejra]] === '''<u>E</u>''' === * [[Edgar Preca]] * [[Edward Sexton]] * [[Edinburgu]] * [[Edward de Bono]] * [[Edwin Hubble]] * [[Efesu]] * [[Eise Eisinga]] *[[Ekonomista]] *[[Ekosistema u Relitt tal-Pajsaġġ Kulturali ta' Lopé-Okanda]] *[[El Escorial]] *[[El Jadida]] *[[El Tajin]] *[[El Torcal]] *[[Eladio Dieste]] *[[Eleonora Jenko Groyer]] *[[Elisha Graves Otis]] *[[Elvas]] *[[Emil Nolde]] *[[Emma Andrijewska]] *[[Emma Muscat]] *[[Ernst Schröder]] *[[Esperantoloġija]] *[[Essaouira]] *[[Estrazzjoni terminoloġika]] *[[Ethel Anderson]] *[[Eugenija Šimkūnaitė]] *[[Eugenio Montale]] *[[Eva Ahnert-Rohlfs]] *[[Evelyn Bonaci]] *[[Évora]] *[[Ewropa tal-Lvant]] === '''<u>F</u>''' === * [[Fabbrika ta' Fagus]] * [[Fabbrika ta' Van Nelle]] * [[Fabbrika tal-Azzar ta' Völklingen]] * [[Fabbrika tal-Ħadid ta' Engelsberg]] * [[Fabbrika tal-Ħarir ta' Tomioka]] * [[Fabbrika tal-Injam u tal-Kartun ta' Verla]] * [[Fabbriki tal-Wied ta' Derwent]] * [[Fanal ta' Cordouan]] * [[Fanjingshan]] * [[Fasil Ghebbi]] * [[Fatehpur Sikri]] * [[Fdalijiet Arkeoloġiċi ta' Moenjodaro]] * [[Fdalijiet ta' Gedi]] * [[Fdalijiet ta' León Viejo]] * [[Fdalijiet ta' Loropéni]] * [[Fdalijiet tal-Vihara Buddista f'Paharpur]] * [[Fehme Agani]] *[[Femminiżmu tar-Rom]] *[[Fenno-Skandinavja]] *[[Fernando Botero]] *[[Ferrara]] *[[Ferruccio Lamborghini]] *[[Festival ta' Sanremo]] *[[Fiera Internazzjonali ta' Rachid Karami f'Tripoli]] *[[Figolla]] *[[Firenze]] *[[Fjord tas-Silġ ta' Ilulissat]] *[[Fjords Norveġiżi tal-Punent]] *[[Flora Martirosian]] *[[Fondoq ta' Ironbridge]] *[[Foresti Antiki u Primordjali tal-Fagu tal-Karpazji u ta' Reġjuni Oħra tal-Ewropa]] *[[Foresti Irkanjani]] *[[Foresti Muntanjużi ta' Odzala-Kokoua]] *[[Foresti Sagri ta' Kaya tal-Mijikenda]] *[[Foresti tas-Siġar tar-Rand ta' Madeira]] *[[Foresti Tropikali ta' Gondwana]] *[[Foresti Tropikali tal-Atsinanana]] *[[Foresti Tropikali u Artijiet Mistagħdra Kolkiċi]] *[[Foresti Verġni ta' Komi]] *[[Formazzjonijiet u Għerien Karstiċi Evaporitiċi tar-Reġjun ta' Emilia Romagna]] *[[Forti l-Aħmar]] * [[Forti ta' Agra]] *[[Forti ta' Bahla]] *[[Forti ta' Galle]] *[[Forti ta' Ġesù]] *[[Forti ta' Rohtas]] *[[Fortifikazzjonijiet fuq in-Naħa tal-Karibew tal-Panama: Portobelo-San Lorenzo]] *[[Fortifikazzjonijiet ta’ Kotor|Fortifikazzjonijiet ta' Kotor]] *[[Fortifikazzjonijiet ta' Vauban]] *[[Fortijiet fl-Għoljiet ta' Rajasthan]] *[[Fortijiet u Kastelli tal-Ghana]] *[[Fortizza ta' Diyarbakır]] *[[Fortizza ta' Hwaseong]] *[[Fortizza ta' Pirot]] *[[Fortizza ta' San Nikola]] *[[Fortizza ta' Suomenlinna]] *[[Fortizzi ta' Dacia fil-Muntanji Orăștie]] *[[Fortizzi Tondi tal-Vikingi]] *[[Foss ta' Messel]] *[[Fotografu]] *[[Francesco Guardi]] *[[François-Alphonse Forel]] *[[François Couperin]] *[[François Girardon]] *[[Francois Mauriac]] *[[Franco Migliacci]] *[[Franġisk Zahra]] *[[Frank Drake]] *[[Franz Beckenbauer]] *[[Franz Kafka]] *[[Franz Ritter von Hauer]] *[[Franz von Suppé]] *[[Frawla]] *[[Fray Bentos]] *[[Frédéric Bartholdi]] *[[Friedrich Georg Wilhelm von Struve]] *[[Fritz Albert Lipmann]] *[[Frosta tal-Għid]] * [[Frott]] * [[Fruntieri Rumani Ġermaniċi t'Isfel]] * [[Fruntieri Rumani ta' Dacia]] * [[Fruntieri Rumani tad-Danubju]] * [[Fruntieri tal-Imperu Ruman]] *[[Fuji]] *[[Furnar]] === '''<u>Ġ</u>''' === * [[Ġardinar]] *[[Ġebla ta' Rosetta]] * [[Ġebla tal-Ġeneral]] * [[Ġeoloġija]] * [[Ġeriko tal-Qedem]] * [[Ġerusalemm]] * [[Ġibjun ta' Bovilla]] * [[Ġibjun ta' Kiev]] * [[Ġnien Botaniku ta' Padova]] * [[Ġnien Persjan]] * [[Ġobon ta' Jāņi]] * [[Ġonna Botaniċi Rjali ta' Kew]] * [[Ġonna Botaniċi ta' Singapore]] * [[Ġonna Klassiċi ta' Suzhou]] * [[Ġonna ta' Hevsel]] * [[Ġonna ta' Shalimar]] *[[Ġurnalist]] === '''<u>G</u>''' === * [[Gammelstad]] * [[Gamzigrad]] * [[Gati tal-Punent]] * [[Gebel Barkal]] * [[Geirangerfjord]] * [[Genova: It-Toroq Ġodda u s-Sistema tal-Palazzi tal-Listi]] *[[Georg Ohm]] *[[Georg von Békésy]] *[[George Gallup]] *[[Georges Bernanos]] *[[Georges J.F. Kohler]] *[[Gerbrand van den Eeckhout]] *[[Getbol, il-Pjanuri tal-Marea tal-Korea t'Isfel]] *[[Ghadamès]] *[[Giacomo Barozzi da Vignola]] *[[Giacomo Zanella]] *[[Giampiero Galeazzi]] *[[Gianni Vella]] *[[Gigi Riva]] *[[Giorgia Meloni]] *[[Giorgio Vasari]] *[[Giosuè Carducci]] *[[Giotto]] *[[Giovanni Arduino]] *[[Giovanni Battista Belzoni]] *[[Giovanni Boccaccio]] *[[Giovanni Paisiello]] *[[Giovanni Papini]] *[[Giulio Natta]] *[[Gjirokastër]] *[[Glossarju]] *[[Göbekli Tepe]] *[[Goffredo Mameli]] *[[Goiás]] *[[Golf ta' California]] *[[Golf ta' Porto]] *[[Gonbad-e Qābus]] *[[Gordion]] *[[Gösta Mittag-Leffler]] *[[Gotiku]] *[[Gozinaki]] *[[Gran Ordni tar-Re Tomislav]] *[[Grand Pré]] *[[Grand-Bassam]] *[[Grand Place, Brussell]] *[[Graz]] *[[Grazia Deledda]] *[[Greenland]] *[[Gregorio Allegri]] *[[Gremxula ta' Malta]] *[[Grotta ta' Chauvet]] *[[Grotti ta' Longmen]] *[[Grotti ta' Yungang]] *[[Grupp ta' Monumenti ta' Khajuraho]] *[[Grupp ta' Monumenti ta' Mahabalipuram]] *[[Guillaume Cornelis van Beverloo]] *[[Guimarães]] *[[Gustave Charpentier]] * [[Gżejjer Eolji]] * [[Gżejjer Falkland]] * [[Gżejjer Galapagos]] * [[Gżejjer Marquesas]] * [[Gżejjer Solovetsky]] * [[Gżejjer Sub-Antartiċi ta' New Zealand]] * [[Gżejjer ta' Amami-Ōshima, ta' Tokunoshima u ta' Iriomote, u t-Tramuntana ta' Okinawa]] * [[Gżejjer ta' Ogasawara]] * [[Gżejjer tal-Blat]] * [[Gżejjer tal-Qroll ta' Aldabra]] * [[Gżejjer tal-Qroll ta' Bikini]] * [[Gżejjer tal-Qroll ta' Rocas]] * [[Gżejjer tan-Nofsinhar u Ibħra Awstrali Franċiżi]] * [[Gżira Heard u l-Gżejjer McDonald]] * [[Gżira Inaċċessibbli]] * [[Gżira Sagra ta' Okinoshima u Siti Assoċjati fir-Reġjun ta' Munakata]] * [[Gżira ta' Cocos]] * [[Gżira ta' Fraser]] * [[Gżira ta' Gorée]] * [[Gżira ta' Henderson]] *[[Gżira ta' Jeju]] *[[Gżira ta' Kunta Kinteh]] *[[Gżira ta' Lord Howe]] *[[Gżira ta' Macquarie]] *[[Gżira ta' Mozambique]] *[[Gżira ta' Pico]] *[[Gżira ta' Robben]] *[[Gżira ta' Saint-Louis]] *[[Gżira ta' Tiwai]] *[[Gżira ta' Wrangel]] *[[Gżira tal-Mużewijiet]] === '''<u>GĦ</u>''' === * [[Għajn Tuffieħa]] * [[Għalliem]] *[[Għar Dalam]] *[[Għar ta' Altamira]] *[[Għar ta' Gorham]] *[[Għar ta' Karain]] *[[Għar ta' Optymistychna]] *[[Għar ta' Vjetrenica]] *[[Għar tal-Apokalissi]] *[[Għar tal-Irħam]] *[[Għar tas-Silġ ta' Dobšiná]] *[[Għarb]] *[[Għelieqi Mtarrġa tar-Ross tal-Cordilleras tal-Filippini]] *[[Għerien Karstiċi ta' Aggtelek u tas-Slovakkja]] *[[Għerien ta' Ajanta]] *[[Għerien ta' Elephanta]] *[[Għerien ta' Ellora]] *[[Għerien ta' Mogao]] *[[Għerien ta’ Škocjan|Għerien ta' Škocjan]] *[[Għerien u Arti tal-Era Glaċjali fil-Jura tas-Swabja]] *[[Għid]] *[[Għoljiet, Djar u Kantini ta' Champagne]] *[[Għoljiet Sagri ta' Piemonte u ta' Lombardia]] *[[Għoljiet ta' Donets]] *[[Għoljiet ta' Matobo]] *[[Għoljiet tal-Prosecco ta' Conegliano u Valdobbiadene]] === '''<u>H</u>''' === * [[Hagia Sophia]] * [[Hahoe]] * [[Haley Bugeja]] * [[Halloumi]] * [[Hallstatt]] * [[Hampi]] *[[Hans Geiger]] *[[Hans Memling]] *[[Hans Spemann]] *[[Harar]] *[[Harry Belafonte]] *[[Hatı Çırpan]] *[[Hatra]] *[[Hattusha]] *[[Hawa Mahal]] *[[Hebron]] *[[Hedeby]] *[[Hegmataneh]] *[[Hegra]] *[[Heinrich Hertz]] *[[Helena Kottler Vurnik]] *[[Henri Fantin-Latour]] *[[Henri Frederic Amiel]] *[[Hermannus Contractus]] *[[Hideki Shirakawa]] *[[Hideki Yukawa]] *[[Hildesheim]] *[[Höga Kusten]] *[[Hoh Xil]] *[[Hội An]] *[[Holašovice]] *[[Hollókő]] *[[Hongcun]] *[[Hospicio Cabañas]] *[[Hospital de Sant Pau]] *[[Hovgården]] *[[Howard Carter]] *[[Hryhorii Kvitka-Osnovianenko]] *[[Huangshan]] *[[Hubert de Givenchy]] === '''<u>Ħ</u>''' === * [[Ħaġar Megalitiku ta' Carnac]] * [[Ħaġar ta' Jelling]] * [[Ħajja]] *[[Ħajt il-Kbir taċ-Ċina]] *[[Ħitan Rumani ta' Lugo]] *[[Ħsad tal-Perli fil-Bahrain]] *[[Ħuta]] === '''<u>I</u>''' === * [[Ibn Battuta]] * [[ICOMOS]] * [[Idolu ta' Shigir]] * [[Idrija]] * [[Idrijski žlikrofi]] * [[Ilha Grande]] * [[Il'ja Prigožini]] * [[Impjant Nukleari ta' Zaporizhzhia]] *[[Impjant tal-Ippompjar bl-Istim ta' Wouda]] *[[Impjanti tan-Nitrat tal-Potassju ta' Humberstone u ta' Santa Laura]] *[[Inara Luigas]] *[[Inċiżjonijiet fuq il-Blat f’Valcamonica|Inċiżjonijiet fuq il-Blat f'Valcamonica]] *[[Independence Hall]] *[[Indiċi]] *[[Industrija tal-lavanja f'Wales]] *[[Ingredjent]] *[[Intaljatur]] *[[Internet]] *[[Ipoġew ta’ Ħal Saflieni|Ipoġew ta' Ħal Saflieni]] * [[Ipproċessar testwali]] * [[Irdumijiet ta' Bandiagara]] * [[Iremel]] * [[Irħula Antiki ta' Djenné]] * [[Irħula Kbar bi Spa fl-Ewropa]] * [[Irpin]] * [[Irziezet Imżejnin ta' Hälsingland]] *[[Isabella d'Este]] *[[ISBN]] *[[Istitut tar-Riċerka dwar il-Foresti tal-Malażja]] *[[Istmu Kuronjan]] *[[Ivan Turgenev]] *[[Ivrea]] === '''<u>J</u>''' === * [[Jacinto Benavente]] * [[Jaipur]] * [[Jakob Bogdani]] * [[Jan Novák]] *[[Jantar Mantar, Jaipur]] *[[Jarrod Sammut]] *[[Jean Antoine Houdon]] *[[Jean Dieudonné]] *[[Jean Picard]] *[[Jebel Faya]] *[[Jeddah]] *[[Jodensavanne]] *[[Joggins]] *[[Johann Christian Bach]] *[[Johan Jensen]] *[[John Edward Critien]] *[[John Kendrew]] *[[John Strutt Rayleigh]] *[[Jongmyo]] *[[Jørgen Pedersen Gram]] *[[Josef Hoffman]] *[[Joseph Louis Gay-Lussac]] *[[Joya de Cerén]] *[[Jože Plečnik]] *[[Jules Pascin]] *[[Julia Malinova]] *[[Julia Sanina]] *[[Júlia Sigmond]] *[[Julio Baghy]] *[[Julius Wagner-Jauregg]] *[[Jum il-Ġifa]] *[[Jum il-Lingwa Erżjana]] *[[Jum l-Ewropa]] *[[Jum Zamenhof]] === '''<u>K</u>''' === * [[Kaċċa bl-ajkli]] * [[Kairouan]] * [[Kaja Kallas]] *[[Kalwaria Zebrzydowska]] *[[Kampnari tal-Belġju u ta' Franza]] *[[Kanal il-Kbir (iċ-Ċina)]] *[[Kanal ta' Rideau]] *[[Kanali ta' Amsterdam]] *[[Kandy]] *[[Kappella]] *[[Karavanseraj Persjani]] *[[Karbalayi Safikhan Karabakhi]] *[[Karl Ferdinand Braun]] *[[Karl Weierstrass]] *[[Karlskrona]] *[[Karlu III]] *[[Kasbah tal-Alġier]] *[[Kaskati ta' Galdelsha]] *[[Kaskati ta' Vitorja]] *[[Kastell ta' Ankara]] *[[Kastell ta' Durham]] *[[Kastell ta' Himeji]] *[[Kastell ta’ Kroměříž|Kastell ta' Kroměříž]] *[[Kastell ta' Kronborg]] *[[Kastell ta' Kuressaare]] *[[Kastell ta’ Litomyšl|Kastell ta' Litomyšl]] *[[Kastell ta' Lubart]] *[[Kastell ta’ Malbork|Kastell ta' Malbork]] *[[Kastell ta' Nesvizh]] *[[Kastell ta' Neuschwanstein]] *[[Kastell ta' Paphos]] *[[Kastell ta' San Pedro de la Roca]] *[[Kastell ta' Spiš]] *[[Kastell ta' Wartburg]] *[[Kastell ta' Zerzevan]] *[[Kastelli ta' Augustusburg u Falkenlust fi Brühl]] *[[Kastelli ta' Bellinzona]] *[[Kastelli u Swar tal-Irħula tar-Re Dwardu fi Gwynedd]] *[[Katarina Vitale]] * [[Katidral]] *[[Katidral ta' Aachen]] *[[Katidral ta' Amiens]] *[[Katidral ta' Bourges]] *[[Katidral ta' Burgos]] *[[Katidral ta' Canterbury]] *[[Katidral ta' Chartres]] *[[Katidral ta' Köln]] *[[Katidral ta' León, Nikaragwa]] *[[Katidral ta' Naumburg]] *[[Katidral ta' Reims]] *[[Katidral ta' Roskilde]] *[[Katidral ta' Santa Sofija (Kiev)]] *[[Katidral ta’ Šibenik|Katidral ta' Šibenik]] *[[Katidral ta' Speyer]] *[[Katidral ta' Tournai]] *[[Katidral ta' Zvartnots]] *[[Katidral tat-Trasfigurazzjoni, Dnipro]] *[[Katina Muntanjuża ta' Ennedi]] *[[Katina Muntanjuża ta’ Meskheti]] *[[Katina Muntanjuża ta' Mulanje]] *[[Katsiaryna Barysevich]] *[[Kauksi Ülle]] *[[Kaunas]] *[[Kavallier ta' Madara]] * [[Kavallier ta’ San Ġakbu|Kavallier ta' San Ġakbu]] * [[Kawkasu tal-Punent]] * [[KazCosmos]] *[[Kelma]] *[[Kerkuane]] *[[Kernavė]] *[[Kewkbet is-Safar]] *[[Khafre]] *[[Khami]] *[[Khinalug]] *[[Khiva]] *[[Khor Rori]] *[[Khorramabad]] *[[Khuttal]] *[[Kibbeh]] *[[Kiki Kogelnik]] *[[Kinderdijk]] *[[Kirurgu]] *[[Kizhi Pogost]] *[[Kladruby nad Labem]] * [[Klima ta' Malta]] * [[Klondike]] * [[Kluane / Wrangell–St. Elias / Bajja tal-Glaċieri / Tatshenshini-Alsek]] * [[Knarik Vardanyan]] * [[Knejjes Barokki tal-Filippini]] * [[Knejjes Imħaffrin fil-Blat ta' Ivanovo]] * [[Knejjes Imħaffrin fil-Blat ta' Lalibela]] *[[Knejjes Impittrin fir-Reġjun ta’ Troodos|Knejjes Impittrin fir-Reġjun ta' Troodos]] *[[Knejjes Rumaneski Katalani tal-Vall de Boí]] *[[Knejjes ta' Chiloé]] *[[Knejjes tal-Injam ta' Maramureș]] *[[Knejjes tal-Injam tal-Karpazji Slovakki]] *[[Knejjes tal-Injam tan-Nofsinhar ta’ Małopolskie]] *[[Knejjes tal-Iskola tal-Arkitettura ta' Pskov]] *[[Knejjes tal-Moldavja]] *[[Knejjes tal-Paċi]] *[[Knejjes u Kunventi ta' Goa]] *[[Knisja Antika ta' Petäjävesi]] *[[Knisja ta' Atlántida]] *[[Knisja ta' Boyana]] *[[Knisja ta' San Ġwann f'Kaneo]] *[[Knisja ta' San Nikola tas-Saqaf]] *[[Knisja ta' Santa Margerita]] *[[Knisja ta' Santa Marija tal-Grazzji (Milan)|Knisja ta' Santa Marija tal-Grazzji, Milan]] *[[Knisja tal-Injam ta' Urnes]] *[[Knisja tal-Paċi fi Świdnica]] *[[Knisja tal-Pellegrinaġġ ta' San Ġwann ta' Nepomuk|Knisja tal-Pellegrinaġġ ta’ San Ġwann ta' Nepomuk]] *[[Knisja tal-Pellegrinaġġi ta' Wies]] *[[Knisja tal-Verġni Marija ta' Arakos]] *[[Knisja tal-Vitorja]] *[[Koh Ker]] *[[Kok]] *[[Kolomenskoye]] *[[Kolonja tal-Artisti ta' Darmstadt]] *[[Kolonji tal-Benevolenza]] *[[Kolonna ta' Ġuljanu]] *[[Kolonna tat-Trinità Mqaddsa, Olomouc]] * [[Kolossew]] * [[Konso]] *[[Konversazzjoni]] *[[Korfù]] *[[Kosta Ġurassika]] *[[Kosta ta' Amalfi]] *[[Kosta ta' Ningaloo]] *[[Kostituzzjoni ta’ Malta|Kostituzzjoni ta' Malta]] *[[Kotlovina]] *[[Koutammakou]] *[[Krak des Chevaliers]] *[[Krakovja]] *[[Krater ta' Logoisk]] *[[Krater ta' Vredefort]] *[[Kremlin ta' Kazan]] *[[Kremlin ta’ Moska|Kremlin ta' Moska]] *[[Kreta]] *[[Krisztina Tóth]] *[[Krzemionki]] *[[Ksour Antiki ta' Ouadane, Chinguetti, Tichitt u Oualata]] *[[Kubdari]] *[[Kujataa]] *[[Kulangsu]] *[[Kuldīga]] *[[Kulleġġ Navali Rjali Antik]] *[[Kultura ta' Chaco]] *[[Kultura ta' Chinchorro]] *[[Kultura ta' Liangzhu]] *[[Kumpanija Ferrovjarja Retika]] *[[Kumpless Modern ta' Pampulha]] *[[Kumpless Monumentali ta' Brâncuși f'Târgu Jiu]] *[[Kumpless ta' Konservazzjoni tal-Amażonja Ċentrali]] *[[Kumpless ta' W-Arly-Pendjari]] *[[Kumpless tal-Bażar Storiku ta' Tabriz]] *[[Kumpless tal-Foresti ta' Dong Phayayen-Khao Yai]] *[[Kumpless tal-Foresta ta' Kaeng Krachan]] *[[Kumpless tal-Kastell ta' Mir]] *[[Kumpless tal-Khānegāh u tas-Santwarju tax-Xejikk Safi al-din f'Ardabil]] *[[Kumpless tal-Monumenti ta' Huế]] *[[Kumpless tal-Muntanji u tat-Tempji ta' Chengde]] *[[Kumpless tal-Oqbra ta' Koguryo]] *[[Kumpless tal-Pajsaġġ ta' Tràng An]] *[[Kumpless u l-Estancias tal-Ġiżwiti ta' Córdoba]] *[[Kumplessi Monastiċi Armeni tal-Iran]] *[[Kumplessi Petroglifiċi tal-Altai tal-Mongolja]] *[[Kumplessi Sagri tal-Hoysala]] *[[Kumitat tal-Wirt Dinji]] *[[Kunvent Benedittin ta' San Ġwann f'Müstair]] *[[Kunvent ta' Kristu f'Tomar]] *[[Kunvent ta' Spiš]] *[[Kunvent ta’ Novodevichy|Kunvent ta' Novodevichy]] *[[Kunya-Urgench]] *[[Kuruna ta' Zvonimir]] *[[Kutná Hora]] === '''<u>L</u>''' === * [[L-Arti]] * [[L-Ewwel Mara jew Raġel ta' Malta]] * [[Lag ta' Baikal]] * [[Lag ta' Brebeneskul]] * [[Lag ta' Kezenoyam]] * [[Lag ta' Laach]] * [[Lag tal-Punent, Hangzhou]] * [[Lagi ta' Ounianga]] * [[Lag ta' Skadar]] * [[Lagi ta' Willandra]] * [[Lake District]] * [[Lamu]] *[[Landier]] *[[Lapponja Żvediża]] *[[Las Médulas]] *[[Lascaux]] *[[Lavaux]] *[[Lavra tat-Trinità ta' San Serġjo]] *[[Lazzaro Pisani]] *[[Le Corbusier]] *[[Le Havre]] *[[Le Locle]] *[[Leptis Magna]] *[[Lessikoloġija]] * [[Lessiku]] * [[Letoon]] * [[Lev Davidovich Landau]] * [[Lev Semenovič Pontrjagin]] * [[Levoča, il-Kastell ta' Spiš u l-monumenti kulturali assoċjati]] * [[Levuka]] * [[Leyla Mammadbeyova]] * [[Liftijiet Idrawliċi tal-Canal du Centre]] *[[Lika Kavzharadze]] *[[Lima]] *[[Lingwa Erżjana]] *[[Lingwa Ġermaniża]] *[[Linja ferrovjarja ta’ Semmering|Linja ferrovjarja ta' Semmering]] *[[Linja Ferrovjarja Trans-Iranjana]] *[[Linji Ferrovjarji tal-Muntanji tal-Indja]] *[[Linji ta' Nazca]] *[[Linji tal-Ilma Difensivi Olandiżi]] *[[Lista ta’ binjiet ta’ Gaudí]] *[[Lista ta' kumpaniji elenkati fil-Borża ta' Malta]] *[[Lista ta' Membri tal-Parlament ta' Malta, 2017–2022]] *[[Lista ta' peniżoli]] *[[Lista ta' Siti ta' Wirt Dinji f'Andorra]] *[[Lista ta' Siti ta' Wirt Dinji f'Ċipru]] *[[Lista ta' Siti ta' Wirt Dinji f'Iżrael]] *[[Lista ta' Siti ta' Wirt Dinji f'Kuba]] *[[Lista ta' Siti ta' Wirt Dinji f'Madagascar]] *[[Lista ta' Siti ta' Wirt Dinji f'Malta]] *[[Lista ta' Siti ta' Wirt Dinji f'San Marino]] *[[Lista ta' Siti ta' Wirt Dinji fi Franza]] *[[Lista ta' Siti ta' Wirt Dinji fi Spanja]] *[[Lista ta' Siti ta' Wirt Dinji taċ-Ċekja|Lista ta' Siti ta' Wirt Dinji fiċ-Ċekja]] *[[Lista ta' Siti ta' Wirt Dinji fiċ-Ċilì]] *[[Lista ta' Siti ta' Wirt Dinji fiċ-Ċina]] *[[Lista ta' Siti ta' Wirt Dinji fid-Danimarka]] *[[Lista ta' Siti ta' Wirt Dinji fil-Bangladesh]] *[[Lista ta' Siti ta' Wirt Dinji fil-Belarussja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Belġju]] *[[Lista ta' Siti ta' Wirt Dinji fil-Bożnija-Ħerzegovina]] *[[Lista ta' Siti ta' Wirt Dinji fil-Brażil]] *[[Lista ta' Siti ta' Wirt Dinji fil-Bulgarija]] *[[Lista ta' Siti ta' Wirt Dinji fil-Filippini]] *[[Lista ta' Siti ta' Wirt Dinji fil-Finlandja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Ġappun]] *[[Lista ta' Siti ta' Wirt Dinji fil-Ġermanja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Ġordan]] *[[Lista ta' Siti ta' Wirt Dinji fil-Georgia]] *[[Lista ta' Siti ta' Wirt Dinji fil-Greċja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Jemen]] *[[Lista ta' Siti ta' Wirt Dinji fil-Kambodja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Kanada]] *[[Lista ta' Siti ta' Wirt Dinji fil-Karibew]] *[[Lista ta' Siti ta' Wirt Dinji fil-Każakistan]] *[[Lista ta' Siti ta' Wirt Dinji fil-Kenja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Kirgistan]] *[[Lista ta' Siti ta' Wirt Dinji fil-Kolombja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Korea t'Isfel]] *[[Lista ta' Siti ta' Wirt Dinji fil-Korea ta' Fuq]] *[[Lista ta' Siti ta' Wirt Dinji fil-Kroazja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Laos]] *[[Lista ta' Siti ta' Wirt Dinji fil-Latvja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Litwanja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Lussemburgu]] *[[Lista ta' Siti ta' Wirt Dinji fil-Lvant tal-Asja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Lvant tal-Ewropa]] *[[Lista ta' Siti ta' Wirt Dinji fil-Maċedonja ta' Fuq]] *[[Lista ta' Siti ta' Wirt Dinji fil-Malażja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Marokk]] *[[Lista ta' Siti ta' Wirt Dinji fil-Mauritania]] *[[Lista ta' Siti ta' Wirt Dinji fil-Messiku]] *[[Lista ta' Siti ta' Wirt Dinji fil-Moldova]] *[[Lista ta' Siti ta' Wirt Dinji fil-Mongolja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Montenegro]] *[[Lista ta' Siti ta' Wirt Dinji fil-Myanmar]] *[[Lista ta' Siti ta' Wirt Dinji fil-Pakistan]] *[[Lista ta' Siti ta' Wirt Dinji fil-Palestina]] *[[Lista ta' Siti ta' Wirt Dinji fil-Perù]] *[[Lista ta' Siti ta' Wirt Dinji fil-Polonja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Portugall]] *[[Lista ta' Siti ta' Wirt Dinji fil-Punent tal-Asja]] *[[Lista ta' Siti ta' Wirt Dinji fil-Punent tal-Ewropa]] *[[Lista ta' Siti ta' Wirt Dinji fil-Vjetnam]] *[[Lista ta' Siti ta' Wirt Dinji fin-Nepal]] *[[Lista ta' Siti ta' Wirt Dinji fin-Netherlands]] *[[Lista ta' Siti ta' Wirt Dinji fin-Nofsinhar tal-Asja]] *[[Lista ta' Siti ta' Wirt Dinji fin-Nofsinhar tal-Ewropa]] *[[Lista ta' Siti ta' Wirt Dinji fin-Norveġja]] *[[Lista ta' Siti ta' Wirt Dinji fir-Renju Unit]] *[[Lista ta' Siti ta' Wirt Dinji fir-Rumanija]] *[[Lista ta' Siti ta' Wirt Dinji fir-Russja]] *[[Lista ta' Siti ta' Wirt Dinji fis-Serbja]] *[[Lista ta' Siti ta' Wirt Dinji fis-Sirja]] *[[Lista ta' Siti ta' Wirt Dinji fis-Slovakkja]] *[[Lista ta' Siti ta' Wirt Dinji fis-Slovenja]] *[[Lista ta' Siti ta' Wirt Dinji fis-Sri Lanka]] *[[Lista ta' Siti ta' Wirt Dinji fit-Taġikistan]] *[[Lista ta' Siti ta' Wirt Dinji fit-Tajlandja]] *[[Lista ta' Siti ta' Wirt Dinji fit-Tanzanija]] *[[Lista ta' Siti ta' Wirt Dinji fit-Tramuntana tal-Asja u fl-Asja Ċentrali]] *[[Lista ta' Siti ta' Wirt Dinji fit-Tramuntana tal-Ewropa]] *[[Lista ta' Siti ta' Wirt Dinji fit-Tuneżija]] *[[Lista ta' Siti ta' Wirt Dinji fit-Turkija]] *[[Lista ta' Siti ta' Wirt Dinji fit-Turkmenistan]] *[[Lista ta' Siti ta' Wirt Dinji fix-Xlokk tal-Asja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Afganistan]] *[[Lista ta' Siti ta' Wirt Dinji fl-Afrika]] *[[Lista ta' Siti ta' Wirt Dinji fl-Afrika t'Isfel]] *[[Lista ta' Siti ta' Wirt Dinji fl-Albanija]] *[[Lista ta' Siti ta' Wirt Dinji fl-Amerka Ċentrali]] *[[Lista ta' Siti ta' Wirt Dinji fl-Amerka t'Isfel]] *[[Lista ta' Siti ta' Wirt Dinji fl-Amerka ta' Fuq]] *[[Lista ta' Siti ta' Wirt Dinji fl-Arabja Sawdija]] *[[Lista ta' Siti ta' Wirt Dinji fl-Arġentina]] *[[Lista ta' Siti ta' Wirt Dinji fl-Armenja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Awstralja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Awstrija]] *[[Lista ta' Siti ta' Wirt Dinji fl-Ażerbajġan]] *[[Lista ta' Siti ta' Wirt Dinji fl-Eġittu]] *[[Lista ta' Siti ta' Wirt Dinji fl-Estonja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Etjopja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Indja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Indoneżja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Iran]] *[[Lista ta' Siti ta' Wirt Dinji fl-Irlanda]] *[[Lista ta' Siti ta' Wirt Dinji fl-Istati Għarab]] *[[Lista ta' Siti ta' Wirt Dinji fl-Istati Uniti]] *[[Lista ta' Siti ta' Wirt Dinji fl-Italja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Iżlanda]] *[[Lista ta' Siti ta' Wirt Dinji fl-Iżvezja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Iżvizzera]] *[[Lista ta' Siti ta' Wirt Dinji fl-Oċeanja]] *[[Lista ta' Siti ta' Wirt Dinji fl-Ukrajna]] *[[Lista ta' Siti ta' Wirt Dinji fl-Ungerija]] *[[Lista ta' Siti ta' Wirt Dinji fl-Użbekistan]] *[[Liz Truss]] *[[Loġġa tal-Ħarir]] *[[Longobardi fl-Italja: Postijiet tal-Poter (568-774 W.K.)]] *[[Lorenzo de' Medici]] *[[Lorenzo Gafà]] *[[Lorenzo Valla]] *[[Luang Prabang]] *[[Lübeck]] *[[Lucavsala]] *[[Lucia Piussi]] *[[Lučka Kajfež Bogataj]] *[[Ludmila tal-Boemja]] *[[Ludovico Ariosto]] *[[Ludovico Carracci]] *[[Ludwik Lejzer Zamenhof]] *[[Luigi Boccherini]] *[[Luigi Galvani]] *[[Luigi Pirandello]] *[[Lumbini]] *[[Luna 26]] *[[Lunenburg]] *[[Lvant ta' Rennell]] *[[Lviv]] *[[Lyon]] *[[Lyubov Panchenko]] === '''<u>M</u>''' === * [[Maċedonit]] * [[Machu Picchu]] * [[Madinat Al-Zahra]] *[[Mafkar tal-Paċi ta' Hiroshima]] *[[Magda Šaturová-Seppová]] *[[Maison Carrée]] * [[Malta taħt il-Franċiżi]] *[[Maltin]] *[[Måneskin]] *[[Manhush]] *[[Manto Mavrogenous]] *[[Mantova]] *[[Margaret Abela]] *[[Maria De Filippi]] *[[Maria Dobroniega ta' Kiev]] *[[Maria Grollmuß]] *[[Marian Smoluchowski]] *[[Mario Draghi]] *[[Mário Zagallo]] *[[Marrakesh]] *[[Marta Kos]] *[[Martinu I ta' Sqallija]] *[[Mary Chronopoulou]] *[[Mary Fenech Adami]] *[[Mary Moser]] *[[Masada]] *[[Masġar tal-Palm ta' Elche]] *[[Maurizio Costanzo]] *[[Mawżolew ta’ Khoja Ahmed Yasawi]] *[[Maymand]] *[[Mbanza Kongo]] *[[Medalja ta' Marian Smoluchowski]] *[[Medina ta' Sousse]] *[[Mehmet Ali Ağca]] *[[Melka Kunture]] *[[Mérida (Spanja)]] *[[Merill]] *[[Meroe]] *[[Merv]] *[[Meteora]] *[[Michael Refalo]] *[[Michail Glinka]] *[[Mikhail Ostrogradsky]] *[[Milan]] *[[Mileva Filipović]] *[[Mimoza Kusari-Lila]] *[[Mina tal-Imħabba ta' Klevan]] *[[Minaret ta' Jam]] *[[Minjiera Storika tal-Fidda f'Tarnowskie Góry]] *[[Minjiera tal-Faħam ta' Ombilin]] *[[Minjiera tal-Fidda ta' Iwami Ginzan]] *[[Minjiera tal-Melħ ta’ Wieliczka]] *[[Minjiera tar-Ram ta' Falun]] *[[Minjieri tad-Deheb tal-Gżira ta' Sado]] *[[Minjieri taż-Żnied Neolitiċi ta' Spiennes]] *[[Mira Alečković]] *[[Mirella Freni]] *[[Miroslav Řepa]] *[[Missjonijiet Franġiskani fis-Sierra Gorda ta' Querétaro]] *[[Missjonijiet ta' San Antonio]] *[[Missjonijiet tal-Ġiżwiti fost il-Guarani]] *[[Missjonijiet tal-Ġiżwiti ta' Chiquitos]] *[[Missjonijiet tal-Ġiżwiti ta' La Santísima Trinidad de Paraná u Jesús de Tavarangue]] *[[Mnajdra]] *[[Modena]] *[[Mogħdija tal-Ġgant]] *[[Moidam]] *[[Monasteri fuq ix-xaqlibiet ta' Popocatépetl]] *[[Monasteri ta' Yuso u ta' Suso]] *[[Monasteru ta' Alcobaça]] *[[Monasteru ta' Batalha]] *[[Monasteru ta' Ferapontov]] *[[Monasteru ta' Gelati]] *[[Monasteru ta' Geghard]] *[[Monasteru ta’ Gračanica|Monasteru ta' Gračanica]] *[[Monasteru ta' Haghpat]] *[[Monasteru ta' Hoge]] *[[Monasteru ta' Horezu]] *[[Monasteru ta' Hosios Loukas]] *[[Monasteru ta' Maulbronn]] *[[Monasteru ta' Neghuts]] *[[Monasteru ta' Poblet]] *[[Monasteru ta' Rila]] *[[Monasteru ta' San Ġwann it-Teologu]] *[[Monasteru ta' San Ilarjun]] *[[Monasteru ta' Sanahin]] *[[Monasteru ta' Santa Katarina]] *[[Monasteru ta' Sopoćani]] *[[Monasteru ta' Studenica]] *[[Monasteru ta' Voroneț]] *[[Monasteru tal-Ġlormini]] *[[Monasteru Rjali ta' Santa Marija ta' Guadalupe]] *[[Monika Kryemadhi]] *[[Møns Klint]] *[[Mont-Saint-Michel]] *[[Monte Albán]] *[[Monte San Giorgio]] *[[Monte Titano]] *[[Monticello]] * [[Monument]] * [[Monument Nazzjonali ta' Żimbabwe l-Kbir]] * [[Monumenti Bojod ta' Vladimir u ta' Suzdal]] * [[Monumenti Buddisti fl-inħawi ta' Hōryū-ji]] * [[Monumenti Paleokristjani u Biżantini ta' Thessaloniki]] * [[Monumenti Rumani, il-Katidral ta' San Pietru u l-Knisja tal-Madonna fi Trier]] * [[Monumenti Storiċi f'Novgorod u fl-Inħawi]] * [[Monumenti Storiċi ta' Kjoto Antika (Bliet ta' Kjoto, Uji u Ōtsu)]] * [[Monumenti Storiċi ta' Makli]] *[[Monumenti Storiċi ta' Nara]] *[[Monumenti ta' Oviedo u tar-Renju tal-Asturjas]] *[[Monumenti tal-Ġebel taċ-Ċriev]] *[[Monumenti u Siti Storiċi f'Kaesong]] *[[Monumenti u Siti Storiċi ta' Hiraizumi]] *[[Morelia]] *[[Moritz Cantor]] *[[Moskea Antika ta' Edirne]] *[[Moskea l-Kbira u Sptar ta' Divriği]] *[[Moskea ta' Arif Agha]] *[[Moskea ta’ Selimiye, Edirne]] *[[Moskea tal-Ġimgħa ta' Esfahan]] *[[Moskea tat-Tatari]] *[[Moskej bi stil Sudaniż fit-Tramuntana tal-Kosta tal-Avorju]] *[[Moskej tal-Pilastri tal-Injam tal-Anatolja Medjevali]] *[[Motoori Norinaga]] *[[Mramorje]] *[[Mtskheta]] *[[Mtsvane]] *[[Muhammad al-Idrisi]] *[[Muħammed]] *[[Muniċipju ta' Bremen]] *[[Muntanja Pelée]] *[[Muntanja Qingcheng]] *[[Muntanja ta' Kumgang]] *[[Muntanja Wutai]] *[[Muntanji Blu u John Crow]] *[[Muntanji Makhonjwa ta' Barberton]] *[[Muntanji ta' Homolje]] *[[Muntanji tad-Deheb ta' Altai]] *[[Muntanji tal-Krimea]] *[[Muntanji Wudang]] *[[Muntanji Wuyi]] *[[Mużew Nazzjonali tal-Montenegro]] *[[Mużew ta' Plantin-Moretus]] *[[Mużew ta' Trojja]] *[[Myśliwska]] *[[Mystras]] === '''<u>N</u>''' === * [[Nærøyfjord]] * [[Nadur]] * [[Naftalan]] * [[Nagorno-Karabakh]] * [[Naħla tal-għasel ta' Malta]] * [[Nalanda Mahavihara]] * [[Namhansanseong]] * [[Nancy]] * [[Nan Madol]] *[[Napli]] *[[Naryn-Kala]] *[[Nataliya Kobrynska]] *[[Nea Moni ta' Chios]] *[[Nekropoli]] *[[Nekropoli ta' Beit She'arim]] *[[Nekropoli ta' Monterozzi]] *[[Nemrut Dağı]] *[[Nessebar]] *[[New Lanark]] *[[New Secret (jott)]] *[[Nexhmije Pagarusha]] *[[Nicolas-Claude Fabri de Peiresc]] *[[Nicolas-Joseph Cugnot]] *[[Nicolas Flamel]] *[[Nicolau Coelho]] *[[Nida]] *[[Nika Križnar]] *[[Nikkō]] *[[Nino Ramishvili]] *[[Nisa (Turkmenistan)]] *[[Nisa f’Malta]] *[[Nisa fl-elezzjonijiet ġenerali ta’ Malta]] *[[Nizza]] *[[Norman Morrison]] *[[Nutar]] === '''<u>O</u>''' === * [[Oażi ta' Al-Ahsa]] * [[Olga Tass]] *[[Olimpja]] *[[Olinda]] *[[Ophrys caucasica|''Ophrys caucasica'']] *[[Oplontis]] *[[Opri Venezjani tad-Difiża bejn is-sekli 15 u 17: Stato da Terra – Stato da Mar tal-Punent]] *[[Oqbra imperjali tad-dinastija Xixia]] *[[Oqbra imperjali tad-dinastiji Ming u Qing]] *[[Oqbra Rjali tad-Dinastija Joseon]] *[[Oqbra ta' Mozu]] *[[Oqbra tar-Rejiet ta' Buganda f'Kasubi]] *[[Orthohantavirus]] *[[Ortografija Litwana]] *[[Osservatorji Astronomiċi tal-Università Federali ta' Kazan]] *[[Osservatorju ta' Črni Vrh]] *[[Osservatorju ta' Jodrell Bank]] *[[Osservatorju ta' Rozhen]] *[[Osun-Osogbo]] *[[Otto Toeplitz]] *[[Ouro Preto]] === '''<u>P</u>''' === * [[Pablo Neruda]] * [[Pagoda ta' Vinh Nghiem]] * [[Pajsaġġ Agrikolu tan-Nofsinhar ta' Öland]] * [[Pajsaġġ Arkeoloġiku tal-Ewwel Pjantaġġuni tal-Kafè fix-Xlokk ta' Kuba]] * [[Pajsaġġ Arkeoloġiku tas-Sassanidi fil-Provinċja ta' Fars]] * [[Pajsaġġ Industrijali ta' Blaenavon]] * [[Pajsaġġ Karstiku tan-Nofsinhar taċ-Ċina]] * [[Pajsaġġ Kulturali ta' ǂKhomani]] * [[Pajsaġġi Kulturali ta' Bassari, Fula u Bedik]] * [[Pajsaġġ Kulturali ta' Budj Bim]] * [[Pajsaġġ Kulturali ta' Gedeo]] * [[Pajsaġġ Kulturali ta' Hawraman/Uramanat]] * [[Pajsaġġ Kulturali ta' Le Morne]] * [[Pajsaġġ Kulturali ta’ Lednice-Valtice]] * [[Pajsaġġ Kulturali ta' Sukur]] * [[Pajsaġġ Kulturali tal-Għelieqi Mtarrġa tar-Ross ta' Honghe Hani]] * [[Pajsaġġ Kulturali tal-Kafè tal-Kolombja]] * [[Pajsaġġ Kulturali tal-Lag ta' Kenozero]] * [[Pajsaġġ Kulturali tal-Wied ta' Orkhon]] * [[Pajsaġġ Kulturali tat-Tinqix fuq il-Blat f'Gobustan]] * [[Pajsaġġ Kulturali tat-Tpittir fuq il-Blat ta' Zuojiang]] * [[Pajsaġġ Kulturali u Botaniku ta' Richtersveld]] * [[Pajsaġġ Kulturali u l-Fdalijiet Arkeoloġiċi tal-Wied ta' Bamiyan]] * [[Pajsaġġi Militari tal-Imperu Maratha fl-Indja]] * [[Pajsaġġ tal-Kaċċa Medjevali fit-Tramuntana ta' Zealand]] * [[Pajsaġġ tal-Vinji ta' Piemonte: Langhe-Roero u Monferrato]] * [[Pajsaġġ tax-Xogħol fil-Minjieri ta' Cornwall u l-Punent ta' Devon]] * [[Pajsaġġi ta' Dauria]] * [[Pál Maléter]] * [[Palazz Irjali ta' Aranjuez]] *[[Palazz Irjali ta' Caserta]] *[[Palazz Mariinskyi]] *[[Palazz ta' Blenheim]] *[[Palazz ta’ Djoklezjanu|Palazz ta' Djoklezjanu]] *[[Palazz ta' Drottningholm]] *[[Palazz ta' Eggenberg]] *[[Palazz ta' Fontainebleau]] *[[Palazz ta' Golestan]] *[[Palazz ta' Ishak Paşa]] *[[Palazz ta' Mafra]] *[[Palazz ta' Orbeliani]] *[[Palazz ta' Potala]] *[[Palazz ta’ Schönbrunn|Palazz ta' Schönbrunn]] *[[Palazz ta’ Stoclet|Palazz ta' Stoclet]] *[[Palazz ta' Versailles]] *[[Palazz tal-Khan]] *[[Palazz tas-Sajf]] *[[Palazz tax-Shirvanshah]] *[[Palazzi Minojċi]] *[[Palazzi Rjali ta' Abomey]] *[[Palazzi u Parks ta' Potsdam u Berlin]] *[[Palenque]] *[[Palermo Għarbija-Normanna u l-Katidrali ta' Cefalù u Monreale]] *[[Palestina]] *[[Palianytsia]] *[[Palmaria]] *[[Palmyra]] *[[Pamukkale]] *[[Panamá Viejo]] *[[Papa Ljun XIV]] *[[Papahānaumokuākea]] *[[Paquimé]] *[[Paramaribo]] *[[Park Arkeoloġiku Nazzjonali ta' Tierradentro]] *[[Park Arkeoloġiku ta' Champaner-Pavagadh]] *[[Park Arkeoloġiku ta' Hili]] *[[Park Arkeoloġiku ta' San Agustín]] *[[Park Irjali ta' Studley]] *[[Park Naturali Nazzjonali tal-Karpazji]] *[[Park Naturali ta' Dinara]] *[[Park Nazzjonali ta' Karula]] *[[Park Naturali ta' Korab-Koritnik]] *[[Park Naturali tal-Iskolli tal-Qroll ta' Tubbataha]] *[[Park Naturali tal-Pilastri ta' Lena]] *[[Park Nazzjonali Impenetrabbli ta' Bwindi]] *[[Park Nazzjonali Olimpiku]] *[[Park Nazzjonali Storiku]] *[[Park Nazzjonali Storiku ta' Göreme]] *[[Park Nazzjonali Storiku ta' Trakai]] *[[Park Nazzjonali ta' Alejandro de Humboldt]] *[[Park Nazzjonali ta' Banc d'Arguin]] *[[Park Nazzjonali ta' Beit Guvrin-Maresha]] *[[Park Nazzjonali ta’ Belovezhskaya Pushcha]] *[[Park Nazzjonali ta' Canaima]] *[[Park Nazzjonali ta' Chapada dos Veadeiros]] *[[Park Nazzjonali ta' Chiribiquete]] *[[Park Nazzjonali ta' Chitwan]] *[[Park Nazzjonali ta' Cilento, Vallo di Diano u Alburni]] *[[Park Nazzjonali ta' Coiba]] *[[Park Nazzjonali ta' Comoé]] *[[Park Nazzjonali ta' Darien]] *[[Park Nazzjonali ta' Defileul Jiului]] *[[Park Nazzjonali ta' Desembarco del Granma]] *[[Park Nazzjonali ta' Doñana]] *[[Park Nazzjonali ta' Everglades]] *[[Park Nazzjonali ta’ Fertő-Hanság]] *[[Park Nazzjonali ta' Garajonay]] *[[Park Nazzjonali ta' Garamba]] *[[Park Nazzjonali ta' Great Smoky Mountains]] *[[Park Nazzjonali ta' Gros Morne]] *[[Park Nazzjonali ta' Gunung Mulu]] *[[Park Nazzjonali ta' Hortobágy]] *[[Park Nazzjonali ta' Huascarán]] *[[Park Nazzjonali ta' Ichkeul]] *[[Park Nazzjonali ta' Iguaçu]] *[[Park Nazzjonali ta' Iguazú]] *[[Park Nazzjonali ta' Ivindo]] *[[Park Nazzjonali ta' Kahuzi-Biega]] *[[Park Nazzjonali ta' Kakadu]] *[[Park Nazzjonali ta' Kaziranga]] *[[Park Nazzjonali ta' Khangchendzonga]] *[[Park Nazzjonali ta' Kilimanjaro]] *[[Park Nazzjonali ta' Kinabalu]] *[[Park Nazzjonali ta' Kiskunság]] *[[Park Nazzjonali ta' Komodo]] *[[Park Nazzjonali ta' Lahemaa]] *[[Park Nazzjonali ta' Lençóis Maranhenses]] *[[Park Nazzjonali ta' Lorentz]] *[[Park Nazzjonali ta' Los Alerces]] *[[Park Nazzjonali ta' Los Glaciares]] *[[Park Nazzjonali ta' Los Katíos]] *[[Park Nazzjonali ta' Lushan]] *[[Park Nazzjonali ta' Mammoth Cave]] *[[Park Nazzjonali ta' Manas]] *[[Park Nazzjonali ta' Manú]] *[[Park Nazzjonali ta' Manovo-Gounda St Floris]] *[[Park Nazzjonali ta' Mesa Verde]] *[[Park Nazzjonali ta' Miguasha]] *[[Park Nazzjonali ta' Morne Trois Pitons]] *[[Park Nazzjonali ta' Murujuga]] *[[Park Nazzjonali ta' Nahanni]] *[[Park Nazzjonali ta' Niah]] *[[Park Nazzjonali ta' Niokolo-Koba]] *[[Park Nazzjonali ta' Noel Kempff Mercado]] *[[Park Nazzjonali ta' Nyungwe]] *[[Park Nazzjonali ta' Phong Nha – Kẻ Bàng]] *[[Park Nazzjonali ta' Þingvellir]] *[[Park Nazzjonali ta' Pirin]] *[[Park Nazzjonali ta' Purnululu]] *[[Park Nazzjonali ta' Rapa Nui]] *[[Park Nazzjonali ta' Rio Abiseo]] *[[Park Nazzjonali ta' Sagarmatha]] *[[Park Nazzjonali ta' Salonga]] *[[Park Nazzjonali ta' Sangay]] *[[Park Nazzjonali ta' Sanqingshan]] *[[Park Nazzjonali ta' Serengeti]] *[[Park Nazzjonali ta' Serra da Capivara]] *[[Park Nazzjonali ta' Simien]] *[[Park Nazzjonali ta' Taï]] *[[Park Nazzjonali ta' Talampaya]] *[[Park Nazzjonali ta' Teide]] *[[Park Nazzjonali ta' Tongariro]] *[[Park Nazzjonali ta' Ujung Kulon]] *[[Park Nazzjonali ta' Una]] *[[Park Nazzjonali ta' Vatnajökull]] *[[Park Nazzjonali ta' Virunga]] *[[Park Nazzjonali ta' Yellowstone]] *[[Park Nazzjonali ta' Yosemite]] *[[Park Nazzjonali tal-Biżonti tal-Boskijiet]] *[[Park Nazzjonali tal-Foresta Pluvjali ta' Gola]] *[[Park Nazzjonali tal-Fortizza tal-Għolja ta' Brimstone]] *[[Park Nazzjonali tal-Għadajjar ta' Mana]] *[[Park Nazzjonali tal-Għerien ta' Carlsbad]] *[[Park Nazzjonali tal-Għerien ta' Naracoorte]] *[[Park Nazzjonali tal-Għerien ta' Peruaçu]] *[[Park Nazzjonali tal-Grand Canyon]] *[[Park Nazzjonali tal-Himalayas il-Kbar]] *[[Park Nazzjonali tal-Katina Muntanjuża ta' Rodopi]] *[[Park Nazzjonali tal-Lag tal-Malawi]] *[[Park Nazzjonali tal-Lagi ta’ Plitvice]] *[[Park Nazzjonali tal-Muntanja Dajti]] *[[Park Nazzjonali tal-Muntanja tal-Kenja]] *[[Park Nazzjonali tal-Muntanja Tomorr]] *[[Park Nazzjonali tal-Muntanji ta' Bale]] *[[Park Nazzjonali tal-Muntanji ta' Rwenzori]] *[[Park Nazzjonali tal-Vulkani ta' Hawaii]] *[[Park Nazzjonali tas-Sundarbans]] *[[Park Nazzjonali tat-Taġikistan]] *[[Park Nazzjonali tax-Xmara ta' Taħt l-Art ta' Puerto Princesa]] *[[Park Provinċjali ta' Ischigualasto]] *[[Park Provinċjali ta' Writing-on-Stone]] *[[Park Provinċjali tad-Dinosawri]] *[[Park Storiku ta' Ayutthaya]] *[[Park Storiku ta' Phu Phrabat]] *[[Park Storiku ta' Si Thep]] *[[Park Storiku ta' Sukhothai]] *[[Park ta' Maloti-Drakensberg]] *[[Park ta’ Muskau|Park ta' Muskau]] *[[Park tal-Art Mistagħdra ta' iSimangaliso]] *[[Park tal-Mafkar tar-Rewwixta u tar-Rivoluzzjoni]] *[[Park Trinazzjonali ta' Sangha]] *[[Parks Internazzjonali tal-Paċi ta' Waterton-tal-Glaċieri]] *[[Parks Nazzjonali ta' Nanda Devi u tal-Wied tal-Fjuri]] *[[Parks Nazzjonali tal-Lag ta' Turkana]] *[[Parks Nazzjonali u Statali tas-Siġar tal-Injam tal-Aħmar]] *[[Parks tal-Muntanji tar-Rockies Kanadiżi]] *[[Parmigianino]] *[[Parrukkier]] *[[Pasargadae]] *[[Paseo del Prado]] *[[Patoloġija]] *[[Pattadakal]] *[[Paulo Coelho]] *[[Pavlo Lee]] *[[Pécs]] *[[Pellegrinaġġ ta’ San Ġakbu]] *[[Peña de los Enamorados]] *[[Peniżola]] *[[Peniżola Valdés]] *[[Pergamon]] *[[Peri-Khan Sofiyeva]] *[[Persepolis]] *[[Peter Carl Fabergé]] *[[Péter Magyar]] *[[Pëtr Kapica]] *[[Petra]] *[[Petra Brocková]] *[[Petroglifiċi ta' Bangudae]] *[[Petroglifiċi tal-Lag ta' Onega u l-Baħar Abjad]] *[[Philipp Otto Runge]] *[[Philippi]] *[[Pienza]] *[[Piero Angela]] *[[Pierre Fatou]] *[[Pietro Longhi]] *[[Pietru l-Kbir]] *[[Pimachiowin Aki]] *[[Ping Yao]] *[[Pippo Baudo]] *[[Pirinej-Monte Perdido]] *[[Pitons]] *[[Pitons, Cirques u Rdumijiet tal-Gżira ta' Réunion]] *[[Pjanta]] *[[Pjanura ta' Bărăgan]] *[[Pjanura ta’ Stari Grad]] *[[Pjanura tal-Ġarer]] *[[Pjazza]] *[[Pjazza ta' Naqsh-e Jahan]] * [[Pjazza tal-Mirakli]] * [[Pkhali]] *[[Plamer]] *[[Planetarju Rjali ta' Eise Eisinga]] *[[Pobiti Kamani]] *[[Politika]] *[[Polonnaruwa]] *[[Pont Antik ta’ Mostar]] *[[Pont ta' Forth]] *[[Pont ta' Malabadi]] *[[Pont ta' Mehmed Paša Sokolović]] *[[Pont ta' Vizcaya]] *[[Pont tal-Fjuri]] *[[Pont tal-Paċi, Tbilisi]] *[[Porfirio Barba-Jacob]] *[[Port Royal]] *[[Port ta' Mariupol]] *[[Port ta’ Marsamxett]] *[[Porta Nigra]] *[[Portiċi ta' Bologna]] *[[Porto]] *[[Postijiet Sagri tal-Bahá'i]] *[[Potosí]] *[[Pożati]] *[[Prambanan]] *[[Professjoni]] *[[Proklos]] *[[Promontorju ta' Putorana]] *[[Provins]] *[[Pu'er]] *[[Puebla (belt)]] *[[Pythagoreion]] === '''<u>Q</u>''' === * [[Qabar ta' Askia]] * [[Qabar ta' Humayun]] * [[Qabar Traċjan ta' Kazanlak]] * [[Qabar Traċjan ta' Sveshtari]] * [[Qabża tal-Biżonti Sfrakassati]] * [[Qal'at al-Bahrain]] * [[Qala (Għawdex)]] * [[Qalba Neolitika tal-Gżejjer Orkney]] * [[Qalhat]] * [[Qanat]] * [[Qaryat al-Faw]] * [[Qaytarma]] * [[Qorti Rjali ta' Tiébélé]] * [[Il-Qtugħ ir-Ras ta’ San Ġwann|Qtugħ ir-Ras ta’ San Ġwann Battista (Caravaggio)]] * [[Quanzhou]] * [[Quebrada de Humahuaca]] * [[Quedlinburg]] * [[Quirigua]] * [[Quito]] * [[Quseir Amra]] * [[Qutb Minar]] === '''<u>R</u>''' === * [[Rachid Chouhal]] * [[Raħal Storiku ta' St. George u l-Fortifikazzjonijiet Relatati, Bermuda]] * [[Rammelsberg]] * [[Ramses II]] * [[Rani-ki-Vav]] * [[Ras'ken' Ozks]] * [[Ravenna]] * [[Ravesa Lleshi]] * [[Red Bay]] * [[Regensburg]] * [[Reġjun Naturali, Kulturali u Storiku ta’ Kotor]] * [[Reġjun tal-Estrazzjoni tal-Minerali ta' Erzgebirge/Krušnohoří]] * [[Reġjun tal-Inbid ta' Tokaj]] *[[Reichenau]] *[[Relattività (Maurits Cornelis Escher)]] *[[Rembrandt]] *[[Renata Scotto]] *[[Renju ta' Mapungubwe]] *[[Renju tal-Ġonna ta' Dessau-Wörlitz]] *[[Repubblika Sovjetika ta’ Don|Repubblika Sovjetika ta' Don]] *[[Residenza ta' Würzburg]] *[[Residenza tal-Metropolitani ta' Bukovina u tad-Dalmazja]] *[[Residenzi tal-Familja Savoia]] *[[Residenzi tal-Moderniżmu f'Berlin]] *[[Rettilu]] *[[Rewwixta tal-Qassisin]] *[[Riga]] *[[Risco Caído]] *[[Riversleigh]] *[[Riżerva Ekoloġika ta' Mistaken Point]] *[[Riżerva Forestali ta' Sinharaja]] *[[Riżerva Naturali Stretta tal-Muntanja ta' Nimba]] *[[Riżerva Naturali Stretta tat-Tsingy ta' Bemaraha]] *[[Riżerva Naturali ta' Bashkiriya]] *[[Riżerva Naturali ta' Darwin]] *[[Riżerva Naturali ta’ Kaniv]] *[[Riżerva Naturali ta' Nahal Me'arot]] *[[Riżerva Naturali ta' Okapi]] *[[Riżerva Naturali ta' Selous]] *[[Riżerva Naturali ta' Srebarna]] *[[Riżerva Naturali ta' Tigrovaya Balka]] *[[Riżerva Naturali ta’ Yulen]] *[[Riżerva Naturali tal-Flora fil-Ġibs]] *[[Riżerva Naturali tas-Suriname Ċentrali]] *[[Riżerva ta' Bijosfera ta' El Pinacate u Gran Desierto de Altar]] *[[Riżerva ta' Bijosfera ta' Río Plátano]] *[[Riżerva tal-Bijosfera ta' Tehuacán-Cuicatlán]] *[[Riżerva tal-Bijosfera tal-Baħar l-Iswed]] *[[Riżerva tal-Bijosfera tal-Friefet Monarki]] *[[Riżerva tal-Bijosfera Transkonfinali Ohrid-Prespa]] *[[Riżerva tal-Fawna ta' Dja]] *[[Riżervi Naturali ta' Air u ta' Ténéré]] *[[Riżervi tal-Foresti Atlantiċi tal-Kosta tal-Iskoperti]] *[[Riżervi tal-Foresti Atlantiċi tax-Xlokk]] *[[Riżervi tal-Katina Muntanjuża ta' Talamanca-La Amistad]] *[[Robert Fico]] *[[Robert Wilhelm Bunsen]] *[[Roberto Burle Marx]] *[[Rodi (belt)]] * [[Roi Mata]] * [[Roșia Montană]] * [[Ronald Searle]] * [[Røros]] * [[Rotta tal-Inċens – Bliet tad-Deżert f'Negev]] * [[Rotta Wixárika tas-Siti Sagri lejn Wirikuta]] * [[Rotot ta’ Santiago de Compostela fi Franza]] * [[Royal Exhibition Building]] * [[Róža Domašcyna]] *[[Rudolf Diesel]] *[[Ruggiero Leoncavallo]] === '''<u>S</u>''' === * [[Sabratha]] * [[Saeva Dupka]] * [[Safranbolu]] * [[Saint-Émilion]] * [[Sajjied]] *[[Sala taċ-Ċentenarju]] *[[Salamanca]] *[[Salib ta' Santa Ewfrosina]] *[[Salini Rjali ta' Arc-et-Senans]] *[[Salme Kann]] *[[Saltaire]] *[[Salvatore Accardo]] *[[Salzburg]] *[[Samantha Cristoforetti]] *[[Samarkanda]] *[[Samarra]] *[[Sambor Prei Kuk]] *[[Sammallahdenmäki]] *[[Samuel Deguara]] *[[San Cristóbal de La Laguna]] *[[San Gimignano]] *[[San Lawrenz (Għawdex)]] *[[San Miguel de Allende]] *[[San Pietruburgu]] *[[Sana'a]] *[[Sanchi]] *[[Sandra Milo]] *[[Sandra Mondaini]] *[[Sandro Botticelli]] *[[Sangiran]] *[[Sansa, il-Monasteri Buddisti tal-Muntanji tal-Korea t'Isfel]] *[[Santa Cruz de Mompox]] *[[Santiago de Compostela]] *[[Santiago de Querétaro]] *[[Santiniketan]] *[[Santwarji tal-Għasafar tal-Passa tul il-Kosta tal-Baħar Isfar u l-Golf ta' Bohai]] *[[Santwarji tal-Pandas Ġganteski ta' Sichuan]] *[[Santwarji tan-Natura Selvaġġa ta' Thungyai-Huai Kha Khaeng]] *[[Santwarju Nazzjonali tal-Għasafar ta' Djoudj]] *[[Santwarju ta' Bom Jesus de Matosinhos]] *[[Santwarju ta' Bom Jesus do Monte]] *[[Santwarju ta' Itsukushima]] *[[Santwarju tal-Balieni ta' El Vizcaino]] *[[Santwarju ta' Mỹ Sơn]] *[[Santwarju tal-Fawna u tal-Flora ta' Malpelo]] *[[Santwarju tan-Natura Selvaġġa tal-Katina Muntanjuża ta' Hamiguitan]] *[[São Cristóvão]] *[[São Luís]] *[[Sarazm]] *[[Sardis]] * [[Saryarka]] * [[Sassi ta' Matera]] * [[Satsivi]] *[[Schokland]] *[[Seba’ Għeġubijiet Ġodda tad-Dinja]] *[[Sebastian Brant]] *[[Segovia]] *[[Seka Sablić]] *[[Sengħa]] *[[Seokguram]] *[[Seowon]] *[[Severo Ochoa]] *[[Sevil Shhaideh]] *[[Sewell]] *[[Sferi tal-Ġebel tal-Costa Rica]] *[[SGang Gwaay]] *[[Shahr-e Sukhteh]] *[[Shahrisabz]] *[[Shaken Aimanov]] *[[Shales ta' Maotianshan]] *[[Sheki]] *[[Shennongjia]] *[[Shibam]] *[[Shirakami-Sanchi]] *[[Shiretoko]] *[[Sian Ka'an]] *[[Šibenik]] *[[Sibila Petlevski]] *[[Sidney Webb]] *[[Siega Verde]] *[[Siena]] *[[Sighișoara]] *[[Sigiriya]] *[[Siġra tal-Ballut ta' Stelmužė]] *[[Siġra tal-ballut ta' Tamme-Lauri]] *[[Sikhote-Alin]] *[[Simon Kldiashvili]] *[[Sinagoga Antika (Erfurt)]] *[[Sinéad O'Connor]] *[[Sintra]] *[[Siracusa]] *[[Sistema Idrawlika Storika ta' Shushtar]] *[[Sistema tal-Ġestjoni tal-Ilma ta' Augsburg]] *[[Sistema tat-Toroq tal-Inka]] *[[Sit Agrikolu Bikri ta' Kuk]] *[[Sit arkeoloġiku ta' Al-Balid|Sit Arkeoloġiku ta' Al-Balid]] *[[Sit Arkeoloġiku ta' Atapuerca]] *[[Sit Arkeoloġiku ta’ Paphos]] *[[Sit Arkeoloġiku tal-Maħżen ta' Valongo]] *[[Sit Storiku Nazzjonali ta' San Juan]] *[[Sit Storiku Statali tat-Tumbati tal-Ħamrija ta' Cahokia]] * [[Sit ta' Wirt Dinji]] * [[Sit ta' Wirt Industrijali ta' Rjukan-Notodden]] *[[Sit tad-Dolmens ta' Antequera]] *[[Sit tar-Raġel ta' Peking f'Zhoukoudian]] *[[Siti tad-Dolmens ta' Gochang, Hwasun u Ganghwa]] *[[Siti Arkeoloġiċi ta' Bat, Al-Khutm u Al-Ayn]] *[[Siti Arkeoloġiċi ta' Tarraco]] *[[Siti Awstraljani tal-Fossili tal-Mammiferi]] *[[Siti Ewlenin tal-Estrazzjoni fil-Wallonja]] *[[Siti Funebri u Mfakar tal-Ewwel Gwerra Dinjija (il-Front tal-Punent)]] *[[Siti Kristjani Moħbija fir-Reġjun ta' Nagasaki]] *[[Siti Metallurġiċi Antiki tal-Burkina Faso]] *[[Siti Penitenzjarji Awstraljani]] *[[Siti preistoriċi bil-puntali madwar l-Alpi|Siti Preistoriċi bil-Puntali Madwar l-Alpi]] *[[Siti Preistoriċi ta' Jōmon fit-Tramuntana tal-Ġappun]] *[[Siti Sagri u Rotot ta' Pellegrinaġġ fil-Katina Muntanjuża ta' Kii]] *[[Siti tal-Fossili tal-Ominidi tal-Afrika t'Isfel]] *[[Siti tar-Rivoluzzjoni Industrijali Meiji tal-Ġappun]] *[[Siti tat-Tpittir fuq il-Blat ta' Kondoa]] *[[Siti tat-Tusi]] *[[Skarpan]] *[[Skellig Michael]] *[[Skogskyrkogården]] *[[Skojjattlu tal-art ta' Tian Shan]] *[[Skola Superjuri tal-Mekkanika tal-Armata]] *[[Skoll il-Kbir tal-Qroll]] *[[Skoll tal-Qroll ta' New Caledonia]] *[[Skoll tal-Qroll tal-Belize]] *[[Skorba]] *[[Skrivan]] *[[Slavko Brezoski]] *[[Socotra]] *[[Soltaniyeh]] *[[Songo Mnara]] *[[Sophia Loren]] *[[Sophie Germain]] *[[Sophie Liebknecht]] *[[Söyembikä]] *[[Speicherstadt]] *[[Spinalonga]] *[[Sputnik 5]] *[[Stari Ras]] *[[Statwa]] *[[Statwa ta' Roland ta' Bremen]] *[[Statwa tal-Libertà]] *[[Stazzjon ta' Chhatrapati Shivaji]] *[[Stazzjon tar-Radju ta' Grimeton]] *[[Stećak]] *[[Stepan Erzya]] *[[Stevns Klint]] *[[Stonehenge]] *[[Stone Town]] *[[Strett ta' Hormuz]] *[[Su Nuraxi]] *[[Subak]] *[[Sulaiman-Too]] *[[Sundarbans]] *[[Supra (festa)]] *[[Suq Ċentrali ta' Ljubljana]] *[[Surtsey]] *[[Susa]] *[[Svaneti]] *[[Svetlana Antonovska]] *[[Sviyazhsk]] === '''<u>T</u>''' === * [[Ta' Bakkja]] * [[Ta' Ħaġrat]] * [[Ta' Kandja]] *[[Tabib]] *[[Tadrart Acacus]] *[[Taħdit]] *[[Taishan]] *[[Taj Mahal]] *[[Takalik Abaj]] *[[Takht-e Soleyman]] *[[Takht-i-Bahi]] *[[Takkanot Shum]] *[[Taksim]] *[[Tallinn]] *[[Tamgaly]] *[[Tanġier]] *[[Taos Pueblo]] *[[Taputapuātea]] *[[Tarraco]] *[[Tarzna Navali ta' Antigua u s-Siti Arkeoloġiċi Relatati]] *[[Tassili n'Ajjer]] *[[Taxila]] *[[Tchogha Zanbil]] *[[Te Wahipounamu]] *[[Teatru Akkademiku Reġjonali ta' Donetsk]] *[[Teatru Antik ta’ Epidaurus|Teatru Antik ta' Epidaurus]] *[[Teatru Rjal]] *[[Teatru Ruman ta' Orange]] *[[Teatru tal-Opri Margravjali]] *[[Teatru tal-Opri ta' Sydney]] *[[Tebe (Eġittu)]] *[[Tekniku]] *[[Telč]] *[[Tempji Ħajjin Kbar taċ-Ċola]] * [[Tempji Megalitiċi ta’ Malta u Għawdex|Tempji Megalitiċi ta' Malta u Għawdex]] * [[Tempji ta' Ħal Tarxien]] *[[Tempju ta' Apollo Epikurju f’Bassae|Tempju ta' Apollo Epikurju f'Bassae]] *[[Tempju ta' Asklepju ta' Epidaurus]] *[[Tempju ta' Haeinsa]] *[[Tempju ta' Kakatiya Rudreshwara]] *[[Tempju ta' Mahabodhi]] *[[Tempju ta' Preah Vihear]] *[[Tempju tal-Ġenna]] *[[Tempju tal-Għar ta' Dambulla]] *[[Tempju tax-Xemx ta' Konarak]] *[[Tempju u Ċimiterju ta' Konfuċju u l-Villa tal-Familja Kong f'Qufu]] *[[Teotihuacan]] *[[Tequila (Belt)]] * [[Terminoloġija]] * [[Tetiana Ostashchenko]] * [[Tétouan]] *[[Teżawru]] *[[Theobald Boehm]] *[[Theodore Géricault]] *[[Thimlich Ohinga]] *[[Tholos ta' El Romeral]] *[[Thomas à Kempis]] *[[Thoros ta' Edessa]] *[[Tian Shan]] * [[Tieqa tad-Dwejra]] * [[Tieqa ta' Wied il-Mielaħ]] * [[Tikal]] * [[Timbuktu]] * [[Timgad]] * [[Tina Turner]] * [[Tinetto]] * [[Tino]] * [[Tinqix fuq il-Blat f'Alta]] *[[Tinqix fuq il-Blat f'Tanum]] *[[Tinqix fuq il-Blat fir-Reġjun ta' Ha'il]] *[[Tinqix fuq il-Blat ta' Dazu]] *[[Tinqix ta' Bisotun]] *[[Tipasa]] *[[Tiryns]] *[[Tiwanaku]] *[[Tiya]] *[[Tlacotalpan]] *[[TNMK]] *[[Tobias Michael Carel Asser]] *[[Toledo]] *[[Tomaso Antonio Vitali]] *[[Tomiri]] *[[Toroq tal-Ħarir: il-Kuritur ta' Zarafshan-Karakum]] *[[Toroq tal-Ħarir: in-Network ta' Rotot tal-Kuritur ta' Chang'an-Tianshan]] * [[Torri Mmejjel ta' Pisa]] * [[Torri ta' Belém]] *[[Torri ta' Erkole]] *[[Torri ta' Londra]] *[[Torri tax-Xebba (Baku)]] *[[Torrijiet residenzjali tas-Svan|Torrijiet Residenzjali tas-Svan]] *[[Toruń]] *[[Tpittir fuq il-Blat ta' Sierra de San Francisco]] *[[Tpittir fuq il-Blat tal-Baċir Mediterran Iberiku]] *[[Tpittir fuq il-Blat tal-Għar ta' Shulgan-Tash]] *[[Trattat ta' Kaunas]] *[[Třebíč]] *[[Trinidad, Kuba]] *[[Trogir]] *[[Trojja]] *[[Tropiċi Mistagħdra ta' Queensland]] *[[Tserkva ta' Santa Marija, Owczary]] *[[Tserkva ta' Santa Marija Omm Alla, Chotyniec]] *[[Tserkva tal-Injam tal-Karpazji fil-Polonja u fl-Ukrajna]] *[[Tsodilo]] *[[Tubeteika]] *[[Tulou ta' Fujian|''Tulou'' ta' Fujian]] *[[Tumbati Ċerimonjali tal-Ħamrija ta' Hopewell]] *[[Tumbati Funebri ta' Dilmun]] *[[Tumbati Funebri ta' Gaya]] *[[Tumbati Monumentali tal-Ħamrija ta' Poverty Point]] *[[Turan]] *[[Tutankhamun]] *[[Twyfelfontein]] *[[Tyre]] === '''<u>U</u>''' === * [[Úbeda]] * [[Ugo Foscolo]] *[[Uluru]] *[[Um er-Rasas]] *[[Umm Al-Jimāl]] *[[UNESCO]] *[[Università Iżlamika Russa]] *[[Università Nazzjonali Awtonoma tal-Messiku]] *[[Università ta' Al-Qarawiġin|Università ta' Al-Qarawijin]] *[[Università ta' Coimbra]] *[[Unjoni Sovjetika]] *[[Urbino]] *[['Uruq Bani Mu'arid]] *[[Uxmal]] === '''<u>V</u>''' === * [[Val d'Orcia]] *[[Val di Noto]] *[[Valentyna Radzymovska]] *[[Valeria Bruni Tedeschi]] *[[Vallée de Mai]] *[[Vasco da Gama]] *[[Vat Phou]] *[[Velimir Khlebnikov]] *[[Venera 7]] *[[Verona]] *[[Via Appia]] *[[Victoria Amelina]] *[[Vigan]] *[[Vincent van Gogh]] *[[Vilel u Ġonna tal-Familja Medici]] *[[Villa d'Este]] *[[Villa Romana del Casale]] *[[Villa ta' Adrijanu]] *[[Villa Tugendhat]] *[[Villaġġi Antiki tat-Tramuntana tas-Sirja]] *[[Villaġġi bil-Knejjes Iffortifikati f'Transilvanja]] *[[Villaġġi Storiċi ta' Shirakawa-gō u Gokayama]] *[[Vilnius]] *[[Visby]] *[[Vitaliy Kim]] *[[Vito Volterra]] *[[Vittorio De Sica]] *[[Vjenna]] *[[Vladimir Ashkenazy]] *[[Vlkolínec]] *[[Volodymyr Zelenskyy]] *[[Volubilis]] *[[Võros]] *[[Vulkan tat-Tajn ta’ Lökbatan]] *[[Vulkani ta' Kamchatka]] === '''<u>W</u>''' === * [[Wachau]] * [[Wadi Al-Hitan]] *[[Wadi Rum]] *[[Wales]] *[[Weimar Klassika]] *[[Werrej]] *[[Wied Superjuri tar-Renu Nofsani]] *[[Wied t'Isfel tal-Awash]] *[[Wied ta' Kathmandu]] *[[Wied ta' Loire]] *[[Wied ta' Madriu-Perafita-Claror]] *[[Wied ta' M'zab]] *[[Wied ta' Qadisha]] *[[Wied ta' Viñales]] *[[Wied tal-Fondoq il-Kbir]] *[[Wied tat-Tempji]] *[[Wilhelm Grimm]] *[[Wilhelm Röntgen]] *[[Willem de Sitter]] *[[Willemstad]] *[[William Boeing]] *[[Wirt Arkeoloġiku tal-Wied ta' Lenggong]] *[[Wirt tal-Foresti Tropikali ta' Sumatra]] *[[Wismar]] *[[Władysław Horodecki]] *[[Wolfgang Paul]] === '''<u>X</u>''' === * [[Xanadu]] * [[Xanthos]] * [[Xatt it-Tiben]] *[[Xeff]] *[[Xidi]] *[[Xmara Omo]] *[[Xochicalco]] *[[Xogħlijiet ta' Jože Plečnik f'Ljubljana – Disinn Urban Iċċentrat fuq il-Bniedem]] *[[Xogħol Arkitettoniku ta' Le Corbusier]] *[[Xjenza spazjali]] *[[Xtatol]] === '''<u>Y</u>''' === * [[Yagul]] * [[Yakushima]] * [[Yana Zinkevych]] * [[Yangdong]] * [[Yarmak]] * [[Yaroslavl]] * [[Yazd]] * [[Yeni-Kale]] * [[Yin Xu]] * [[Yllka Mujo]] * [[Yogyakarta]] *[[Yuliya Gushchina]] *[[Yuri Lysianskyi]] === '''<u>Ż</u>''' === * [[Żapoteki]] * [[Żiemel Abjad ta' Osmington]] * [[Żona Kulturali ta' Ḥimā]] *[[Żona l-Kbira tal-Muntanji Blu]] *[[Żona Naturali Selvaġġa tat-Tażmanja]] *[[Żona Protetta ta' Jungfrau-Aletsch]] *[[Żona Protetta ta' Pliva, Janj u r-Riżerva ta' Janjske Otoke]] *[[Żona Protetta tal-Gżejjer Phoenix]] *[[Żona ta' Interess Xeniku u Storiku ta' Huanglong]] *[[Żona ta' Interess Xeniku u Storiku tal-Wied ta' Jiuzhaigou]] *[[Żona ta' Interess Xeniku u Storiku ta' Wulingyuan]] *[[Żona ta' Konservazzjoni ta' Guanacaste]] *[[Żona ta' Konservazzjoni ta' Ngorongoro]] *[[Żona ta' Konservazzjoni ta' Pantanal]] *[[Żona tat-Tpittir fuq il-Blat ta' Chongoni]] *[[Żoni Protetti tar-Reġjun tal-Fjuri tal-Kap]] *[[Żoni Protetti tat-Tliet Xmajjar Paralleli ta' Yunnan]] *[[Żoni Storiċi ta' Baekje]] *[[Żoni Storiċi ta' Gyeongju]] *[[Żooloġija]] === '''<u>Z</u>''' === * [[Zabid]] * [[Zacatecas (belt)]] * [[Zagori]] * [[Zamość]] * [[Žatec]] * [[Žehra]] * [[Ziba Ganiyeva]] * [[Zivana]] * [[Zlata Kolarić-Kišur]] *[[Zofia Zamenhof]] *[[Zollverein]] *[[Zond 5]] *[[Zsuzsanna Lorántffy]] ptspwo1pqa1pe5qflt9yx3feyjwkolw 0 34303 330116 330113 2026-05-17T14:48:44Z Sharon Zarb 28004 Żidt ritratti/artikli 330116 wikitext text/x-wiki {{Stub|bijografija}} {{Infobox bijografija}} [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Roadhouse musicians 1964]] Edmond Zarb twieled il-Ħamrun fit-2 ta’ Marzu 1945. Studja l-Kulleġġ ta’ Stella Maris fil-Gżira. Meta kellu ħames snin, beda jistudja l-pjanu ma’ missieru, Anthony Zarb, li kien mużiċist ukoll. Fl-1967 għamel l-ewwel kuntratt tiegħu bħala pjanista tal-lukanda MALTA HILTON, fejn dam 30 sena u ingħata unur internazzjonali wara biss ħames snin għall-eċċellenza li wera fil-profiċjenza tal-pjanu mal-klijenti u midalja oħra wara 30 sena ta’ dedikazzjoni bla waqfien għas-servizz tiegħu f’qasam li kien passjonat dwaru. Matul is-snin, kiseb bosta suċċessi f’festivals lokali u internazzjonali bil-kanzunetti li kkompona għal kantanti magħrufa Maltin, bħal Joe Cutajar, Enzo Guzman, Catherine Vigar, Marthese Tanti, Renato, Moira Stafrace u oħrajn. Il-karriera tiegħu bħala pjanista f’lukandi prominenti Maltin issoktat il-Phoenicia kif ukoll il-Westin Dragonara. Edmond ma kellux biss namra għall-mużika. Wera wkoll interess kbir għall-kitba fil-lingwa Maltija. Minn dejjem kien iħarbex xi storja qasira li kienet tixxandar fuq il-mezzi tax-xandir ta’ dawk iż-żmenijiet, xi wħud minnhom li nqraw minn Charles Arrigo. F’ Novembru 1979, Twanny Scalpello beda jaqra l-ewwel rumanz tiegħu F’Xifer l-Irdum li ġie ppubblikat fl-1981 bil-koooperazzjoni ta’ David Buġelli. Dan l-ewwel rumanz kien suċċess u ssokta bil-pubblikazzjoni ta’ rumanz ieħor F’Salib it-Toroq, li nqara wkoll fuq Radju Malta minn Twannie Scalpello. Edmond dejjem jammetti li l-karattri tiegħu, għalkemm realistiċi, kien ikollhom tendenza traġika għax ried jirrifletti l-uġigħ li taf tagħti l-ħajja u li huwa kien jesprimi fil-kitba tiegħu, imqanqal b’immaġinazzjoni, ispirat minn natura u b’idejat li kien jislet minn dak li jisma’ u jaqra. Is-sensiela tar-rumanzi tiegħu ssoktat: F’Keffa ta’ Miżien (1981), F’Telfa tal-Ġenn (1983), F’Radda ta’ Salib (1984), F’Telfien id-Dnub (1986), F’Seħer it-Tifkiriet (1988), F’Tgħanniqa mal-Mewt (2001) u F’Taqbida mal-Mewġ (2003). Xi wħud minnhom inqraw fuq il-mezzi tax-xandir u r-rumanz F’Tgħanniqa mal-Mewt ġie adattat għal serje fuq it-televiżjoni Maltija bit-titlu “Tgħanniqa”. Mill-2005 lil hemm, ħareġ sensiela oħra ta’ rumanzi, ffukati fuq il-karattru femminili: Nina, Veronika, Manwela, Sara u l-aħħar wieħed popolari “Emma”, rumanz li nqara diversi drabi fuq il-mezzi tax-xandir. Edmond dejjem stqarr li r-rumanzi tiegħu qatt ma kellhom l-għan li jkunu xi “kapolavur letterarju jew akkademiku” għax l-għan ewlieni tiegħu kien li jagħti pjaċir lin-nies. [[Stampa:Tokyo World Popular Festival 1976 - Malta Song Entry.jpg|daqsminuri|Ir-rappreżentanti ta' Malta fil-Festival ta' Tokyo 1976]] [[Stampa:Piano Concert on Maltese radio of Edmond Zarb in the 1960s on Rediffusion Malta.jpg|daqsminuri|Kunċert tal-pjanu fuq ir-Rediffusion ta' Malta 1964]] Edmond miet fit-2 ta’ April 2026. https://soundcloud.com/edmondzarb https://www.youtube.com/watch?v=jIA4jYT3zIk&list=RDjIA4jYT3zIk&start_radio=1 2msjjimkf7whbmhlctvofqr2dz4qejz 330117 330116 2026-05-17T14:52:04Z Sharon Zarb 28004 Żidt ritratti/artikli 330117 wikitext text/x-wiki {{Stub|bijografija}} {{Infobox bijografija}} [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Roadhouse musicians 1964]] [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Mużiċisti tar-Roadhouse 1964: Mro. Paul Arnand (klarinett), Sammy Galea (Pjanu), Edmond Zarb (bass), Eric Xuereb (drums)]] Edmond Zarb twieled il-Ħamrun fit-2 ta’ Marzu 1945. Studja l-Kulleġġ ta’ Stella Maris fil-Gżira. Meta kellu ħames snin, beda jistudja l-pjanu ma’ missieru, Anthony Zarb, li kien mużiċist ukoll. Fl-1967 għamel l-ewwel kuntratt tiegħu bħala pjanista tal-lukanda MALTA HILTON, fejn dam 30 sena u ingħata unur internazzjonali wara biss ħames snin għall-eċċellenza li wera fil-profiċjenza tal-pjanu mal-klijenti u midalja oħra wara 30 sena ta’ dedikazzjoni bla waqfien għas-servizz tiegħu f’qasam li kien passjonat dwaru. Matul is-snin, kiseb bosta suċċessi f’festivals lokali u internazzjonali bil-kanzunetti li kkompona għal kantanti magħrufa Maltin, bħal Joe Cutajar, Enzo Guzman, Catherine Vigar, Marthese Tanti, Renato, Moira Stafrace u oħrajn. Il-karriera tiegħu bħala pjanista f’lukandi prominenti Maltin issoktat il-Phoenicia kif ukoll il-Westin Dragonara. [[Stampa:Rumanz EMMA by edmond zarb.jpg|daqsminuri|Qoxra tar-rumanz EMMA ta' Edmond Zarb]] Edmond ma kellux biss namra għall-mużika. Wera wkoll interess kbir għall-kitba fil-lingwa Maltija. Minn dejjem kien iħarbex xi storja qasira li kienet tixxandar fuq il-mezzi tax-xandir ta’ dawk iż-żmenijiet, xi wħud minnhom li nqraw minn Charles Arrigo. F’ Novembru 1979, Twanny Scalpello beda jaqra l-ewwel rumanz tiegħu F’Xifer l-Irdum li ġie ppubblikat fl-1981 bil-koooperazzjoni ta’ David Buġelli. Dan l-ewwel rumanz kien suċċess u ssokta bil-pubblikazzjoni ta’ rumanz ieħor F’Salib it-Toroq, li nqara wkoll fuq Radju Malta minn Twannie Scalpello. Edmond dejjem jammetti li l-karattri tiegħu, għalkemm realistiċi, kien ikollhom tendenza traġika għax ried jirrifletti l-uġigħ li taf tagħti l-ħajja u li huwa kien jesprimi fil-kitba tiegħu, imqanqal b’immaġinazzjoni, ispirat minn natura u b’idejat li kien jislet minn dak li jisma’ u jaqra. Is-sensiela tar-rumanzi tiegħu ssoktat: F’Keffa ta’ Miżien (1981), F’Telfa tal-Ġenn (1983), F’Radda ta’ Salib (1984), F’Telfien id-Dnub (1986), F’Seħer it-Tifkiriet (1988), F’Tgħanniqa mal-Mewt (2001) u F’Taqbida mal-Mewġ (2003). Xi wħud minnhom inqraw fuq il-mezzi tax-xandir u r-rumanz F’Tgħanniqa mal-Mewt ġie adattat għal serje fuq it-televiżjoni Maltija bit-titlu “Tgħanniqa”. Mill-2005 lil hemm, ħareġ sensiela oħra ta’ rumanzi, ffukati fuq il-karattru femminili: Nina, Veronika, Manwela, Sara u l-aħħar wieħed popolari “Emma”, rumanz li nqara diversi drabi fuq il-mezzi tax-xandir. Edmond dejjem stqarr li r-rumanzi tiegħu qatt ma kellhom l-għan li jkunu xi “kapolavur letterarju jew akkademiku” għax l-għan ewlieni tiegħu kien li jagħti pjaċir lin-nies. [[Stampa:Tokyo World Popular Festival 1976 - Malta Song Entry.jpg|daqsminuri|Ir-rappreżentanti ta' Malta fil-Festival ta' Tokyo 1976]] [[Stampa:Piano Concert on Maltese radio of Edmond Zarb in the 1960s on Rediffusion Malta.jpg|daqsminuri|Kunċert tal-pjanu fuq ir-Rediffusion ta' Malta 1964]] Edmond miet fit-2 ta’ April 2026. https://soundcloud.com/edmondzarb https://www.youtube.com/watch?v=jIA4jYT3zIk&list=RDjIA4jYT3zIk&start_radio=1 6ekfwj0x6tf8lmktzwkt65aagncfk3f 330118 330117 2026-05-17T14:53:59Z Sharon Zarb 28004 ritratt 330118 wikitext text/x-wiki {{Stub|bijografija}} {{Infobox bijografija}} [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Roadhouse musicians 1964]] [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Mużiċisti tar-Roadhouse 1964: Mro. Paul Arnand (klarinett), Sammy Galea (Pjanu), Edmond Zarb (bass), Eric Xuereb (drums)]] [[Stampa:F'Radda ta' Salib by Edmond Zarb.jpg|daqsminuri|Qoxra tar-rumanz F'Radda ta' Salib ta' Edmond Zarb]] Edmond Zarb twieled il-Ħamrun fit-2 ta’ Marzu 1945. Studja l-Kulleġġ ta’ Stella Maris fil-Gżira. Meta kellu ħames snin, beda jistudja l-pjanu ma’ missieru, Anthony Zarb, li kien mużiċist ukoll. Fl-1967 għamel l-ewwel kuntratt tiegħu bħala pjanista tal-lukanda MALTA HILTON, fejn dam 30 sena u ingħata unur internazzjonali wara biss ħames snin għall-eċċellenza li wera fil-profiċjenza tal-pjanu mal-klijenti u midalja oħra wara 30 sena ta’ dedikazzjoni bla waqfien għas-servizz tiegħu f’qasam li kien passjonat dwaru. Matul is-snin, kiseb bosta suċċessi f’festivals lokali u internazzjonali bil-kanzunetti li kkompona għal kantanti magħrufa Maltin, bħal Joe Cutajar, Enzo Guzman, Catherine Vigar, Marthese Tanti, Renato, Moira Stafrace u oħrajn. Il-karriera tiegħu bħala pjanista f’lukandi prominenti Maltin issoktat il-Phoenicia kif ukoll il-Westin Dragonara. [[Stampa:Rumanz EMMA by edmond zarb.jpg|daqsminuri|Qoxra tar-rumanz EMMA ta' Edmond Zarb]] Edmond ma kellux biss namra għall-mużika. Wera wkoll interess kbir għall-kitba fil-lingwa Maltija. Minn dejjem kien iħarbex xi storja qasira li kienet tixxandar fuq il-mezzi tax-xandir ta’ dawk iż-żmenijiet, xi wħud minnhom li nqraw minn Charles Arrigo. F’ Novembru 1979, Twanny Scalpello beda jaqra l-ewwel rumanz tiegħu F’Xifer l-Irdum li ġie ppubblikat fl-1981 bil-koooperazzjoni ta’ David Buġelli. Dan l-ewwel rumanz kien suċċess u ssokta bil-pubblikazzjoni ta’ rumanz ieħor F’Salib it-Toroq, li nqara wkoll fuq Radju Malta minn Twannie Scalpello. Edmond dejjem jammetti li l-karattri tiegħu, għalkemm realistiċi, kien ikollhom tendenza traġika għax ried jirrifletti l-uġigħ li taf tagħti l-ħajja u li huwa kien jesprimi fil-kitba tiegħu, imqanqal b’immaġinazzjoni, ispirat minn natura u b’idejat li kien jislet minn dak li jisma’ u jaqra. Is-sensiela tar-rumanzi tiegħu ssoktat: F’Keffa ta’ Miżien (1981), F’Telfa tal-Ġenn (1983), F’Radda ta’ Salib (1984), F’Telfien id-Dnub (1986), F’Seħer it-Tifkiriet (1988), F’Tgħanniqa mal-Mewt (2001) u F’Taqbida mal-Mewġ (2003). Xi wħud minnhom inqraw fuq il-mezzi tax-xandir u r-rumanz F’Tgħanniqa mal-Mewt ġie adattat għal serje fuq it-televiżjoni Maltija bit-titlu “Tgħanniqa”. Mill-2005 lil hemm, ħareġ sensiela oħra ta’ rumanzi, ffukati fuq il-karattru femminili: Nina, Veronika, Manwela, Sara u l-aħħar wieħed popolari “Emma”, rumanz li nqara diversi drabi fuq il-mezzi tax-xandir. Edmond dejjem stqarr li r-rumanzi tiegħu qatt ma kellhom l-għan li jkunu xi “kapolavur letterarju jew akkademiku” għax l-għan ewlieni tiegħu kien li jagħti pjaċir lin-nies. [[Stampa:Tokyo World Popular Festival 1976 - Malta Song Entry.jpg|daqsminuri|Ir-rappreżentanti ta' Malta fil-Festival ta' Tokyo 1976]] [[Stampa:Piano Concert on Maltese radio of Edmond Zarb in the 1960s on Rediffusion Malta.jpg|daqsminuri|Kunċert tal-pjanu fuq ir-Rediffusion ta' Malta 1964]] Edmond miet fit-2 ta’ April 2026. https://soundcloud.com/edmondzarb https://www.youtube.com/watch?v=jIA4jYT3zIk&list=RDjIA4jYT3zIk&start_radio=1 9cz6348nwvz4q9ahamai8v1vpt6lh3d 330119 330118 2026-05-17T15:02:56Z Sharon Zarb 28004 Żidt ritratti/artikli 330119 wikitext text/x-wiki {{Stub|bijografija}} {{Infobox bijografija}} [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Roadhouse musicians 1964]] [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Mużiċisti tar-Roadhouse 1964: Mro. Paul Arnand (klarinett), Sammy Galea (Pjanu), Edmond Zarb (bass), Eric Xuereb (drums)]] [[Stampa:F'Radda ta' Salib by Edmond Zarb.jpg|daqsminuri|Qoxra tar-rumanz F'Radda ta' Salib ta' Edmond Zarb]] [[Stampa:Literature review of the book Nina by Edmond Zarb published in The Sunday Times 10 July 2005.jpg|daqsminuri|Artiklu dwar il-pubblikazzjoni tar-rumanz NINA ta' Edmond Zarb.]] Edmond Zarb twieled il-Ħamrun fit-2 ta’ Marzu 1945. Studja l-Kulleġġ ta’ Stella Maris fil-Gżira. Meta kellu ħames snin, beda jistudja l-pjanu ma’ missieru, Anthony Zarb, li kien mużiċist ukoll. Fl-1967 għamel l-ewwel kuntratt tiegħu bħala pjanista tal-lukanda MALTA HILTON, fejn dam 30 sena u ingħata unur internazzjonali wara biss ħames snin għall-eċċellenza li wera fil-profiċjenza tal-pjanu mal-klijenti u midalja oħra wara 30 sena ta’ dedikazzjoni bla waqfien għas-servizz tiegħu f’qasam li kien passjonat dwaru. Matul is-snin, kiseb bosta suċċessi f’festivals lokali u internazzjonali bil-kanzunetti li kkompona għal kantanti magħrufa Maltin, bħal Joe Cutajar, Enzo Guzman, Catherine Vigar, Marthese Tanti, Renato, Moira Stafrace u oħrajn. Il-karriera tiegħu bħala pjanista f’lukandi prominenti Maltin issoktat il-Phoenicia kif ukoll il-Westin Dragonara. [[Stampa:Rumanz EMMA by edmond zarb.jpg|daqsminuri|Qoxra tar-rumanz EMMA ta' Edmond Zarb]] Edmond ma kellux biss namra għall-mużika. Wera wkoll interess kbir għall-kitba fil-lingwa Maltija. Minn dejjem kien iħarbex xi storja qasira li kienet tixxandar fuq il-mezzi tax-xandir ta’ dawk iż-żmenijiet, xi wħud minnhom li nqraw minn Charles Arrigo. F’ Novembru 1979, Twanny Scalpello beda jaqra l-ewwel rumanz tiegħu F’Xifer l-Irdum li ġie ppubblikat fl-1981 bil-koooperazzjoni ta’ David Buġelli. Dan l-ewwel rumanz kien suċċess u ssokta bil-pubblikazzjoni ta’ rumanz ieħor F’Salib it-Toroq, li nqara wkoll fuq Radju Malta minn Twannie Scalpello. Edmond dejjem jammetti li l-karattri tiegħu, għalkemm realistiċi, kien ikollhom tendenza traġika għax ried jirrifletti l-uġigħ li taf tagħti l-ħajja u li huwa kien jesprimi fil-kitba tiegħu, imqanqal b’immaġinazzjoni, ispirat minn natura u b’idejat li kien jislet minn dak li jisma’ u jaqra. Is-sensiela tar-rumanzi tiegħu ssoktat: F’Keffa ta’ Miżien (1981), F’Telfa tal-Ġenn (1983), F’Radda ta’ Salib (1984), F’Telfien id-Dnub (1986), F’Seħer it-Tifkiriet (1988), F’Tgħanniqa mal-Mewt (2001) u F’Taqbida mal-Mewġ (2003). Xi wħud minnhom inqraw fuq il-mezzi tax-xandir u r-rumanz F’Tgħanniqa mal-Mewt ġie adattat għal serje fuq it-televiżjoni Maltija bit-titlu “Tgħanniqa”. Mill-2005 lil hemm, ħareġ sensiela oħra ta’ rumanzi, ffukati fuq il-karattru femminili: Nina, Veronika, Manwela, Sara u l-aħħar wieħed popolari “Emma”, rumanz li nqara diversi drabi fuq il-mezzi tax-xandir. Edmond dejjem stqarr li r-rumanzi tiegħu qatt ma kellhom l-għan li jkunu xi “kapolavur letterarju jew akkademiku” għax l-għan ewlieni tiegħu kien li jagħti pjaċir lin-nies. [[Stampa:Tokyo World Popular Festival 1976 - Malta Song Entry.jpg|daqsminuri|Ir-rappreżentanti ta' Malta fil-Festival ta' Tokyo 1976]] [[Stampa:Piano Concert on Maltese radio of Edmond Zarb in the 1960s on Rediffusion Malta.jpg|daqsminuri|Kunċert tal-pjanu fuq ir-Rediffusion ta' Malta 1964]] Edmond miet fit-2 ta’ April 2026. https://soundcloud.com/edmondzarb https://www.youtube.com/watch?v=jIA4jYT3zIk&list=RDjIA4jYT3zIk&start_radio=1 https://whoswho.mt/en/his-music-filled-our-lobby-westin-dragonara-pays-its-respects-to-pianist-edmond-zarb<ref name=":0">Din l-informazzjoni nkitbet mill-familja ta' Edmond Zarb u r-ritratti u l-istampi huma oriġinali mill-arkivji tal-pjanist/awtur/kompożitur.</ref> https://www.linkedin.com/posts/westin-dragonara-resort_for-over-25-years-edmond-zarbs-music-filled-activity-7447901190119661568-wl9j/<ref name=":0" /> https://www.facebook.com/Westinmalta/photos/for-over-25-years-edmond-zarbs-music-filled-our-lobby-and-touched-the-hearts-of-/1408150994685372/ nkusj9sklk5jcnxehwl09pq34et3i1b 330120 330119 2026-05-17T15:03:49Z Sharon Zarb 28004 bidla żgħira 330120 wikitext text/x-wiki {{Stub|bijografija}} {{Infobox bijografija}} [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Roadhouse musicians 1964]] [[Stampa:Roadhouse musicians 1964.jpg|daqsminuri|Mużiċisti tar-Roadhouse 1964: Mro. Paul Arnand (klarinett), Sammy Galea (Pjanu), Edmond Zarb (bass), Eric Xuereb (drums)]] [[Stampa:F'Radda ta' Salib by Edmond Zarb.jpg|daqsminuri|Qoxra tar-rumanz F'Radda ta' Salib ta' Edmond Zarb]] [[Stampa:Literature review of the book Nina by Edmond Zarb published in The Sunday Times 10 July 2005.jpg|daqsminuri|Artiklu dwar il-pubblikazzjoni tar-rumanz NINA ta' Edmond Zarb.]] Edmond Zarb twieled il-Ħamrun fit-2 ta’ Marzu 1945. Studja l-Kulleġġ ta’ Stella Maris fil-Gżira. Meta kellu ħames snin, beda jistudja l-pjanu ma’ missieru, Anthony Zarb, li kien mużiċist ukoll. Fl-1967 għamel l-ewwel kuntratt tiegħu bħala pjanista tal-lukanda MALTA HILTON, fejn dam 30 sena u ingħata unur internazzjonali wara biss ħames snin għall-eċċellenza li wera fil-profiċjenza tal-pjanu mal-klijenti u midalja oħra wara 30 sena ta’ dedikazzjoni bla waqfien għas-servizz tiegħu f’qasam li kien passjonat dwaru. Matul is-snin, kiseb bosta suċċessi f’festivals lokali u internazzjonali bil-kanzunetti li kkompona għal kantanti magħrufa Maltin, bħal Joe Cutajar, Enzo Guzman, Catherine Vigar, Marthese Tanti, Renato, Moira Stafrace u oħrajn. Il-karriera tiegħu bħala pjanista f’lukandi prominenti Maltin issoktat il-Phoenicia kif ukoll il-Westin Dragonara. [[Stampa:Rumanz EMMA by edmond zarb.jpg|daqsminuri|Qoxra tar-rumanz EMMA ta' Edmond Zarb]] Edmond ma kellux biss namra għall-mużika. Wera wkoll interess kbir għall-kitba fil-lingwa Maltija. Minn dejjem kien iħarbex xi storja qasira li kienet tixxandar fuq il-mezzi tax-xandir ta’ dawk iż-żmenijiet, xi wħud minnhom li nqraw minn Charles Arrigo. F’ Novembru 1979, Twanny Scalpello beda jaqra l-ewwel rumanz tiegħu F’Xifer l-Irdum li ġie ppubblikat fl-1981 bil-koooperazzjoni ta’ David Buġelli. Dan l-ewwel rumanz kien suċċess u ssokta bil-pubblikazzjoni ta’ rumanz ieħor F’Salib it-Toroq, li nqara wkoll fuq Radju Malta minn Twannie Scalpello. Edmond dejjem jammetti li l-karattri tiegħu, għalkemm realistiċi, kien ikollhom tendenza traġika għax ried jirrifletti l-uġigħ li taf tagħti l-ħajja u li huwa kien jesprimi fil-kitba tiegħu, imqanqal b’immaġinazzjoni, ispirat minn natura u b’idejat li kien jislet minn dak li jisma’ u jaqra. Is-sensiela tar-rumanzi tiegħu ssoktat: F’Keffa ta’ Miżien (1981), F’Telfa tal-Ġenn (1983), F’Radda ta’ Salib (1984), F’Telfien id-Dnub (1986), F’Seħer it-Tifkiriet (1988), F’Tgħanniqa mal-Mewt (2001) u F’Taqbida mal-Mewġ (2003). Xi wħud minnhom inqraw fuq il-mezzi tax-xandir u r-rumanz F’Tgħanniqa mal-Mewt ġie adattat għal serje fuq it-televiżjoni Maltija bit-titlu “Tgħanniqa”. Mill-2005 lil hemm, ħareġ sensiela oħra ta’ rumanzi, ffukati fuq il-karattru femminili: Nina, Veronika, Manwela, Sara u l-aħħar wieħed popolari “Emma”, rumanz li nqara diversi drabi fuq il-mezzi tax-xandir. Edmond dejjem stqarr li r-rumanzi tiegħu qatt ma kellhom l-għan li jkunu xi “kapolavur letterarju jew akkademiku” għax l-għan ewlieni tiegħu kien li jagħti pjaċir lin-nies. [[Stampa:Tokyo World Popular Festival 1976 - Malta Song Entry.jpg|daqsminuri|Ir-rappreżentanti ta' Malta fil-Festival ta' Tokyo 1976]] [[Stampa:Piano Concert on Maltese radio of Edmond Zarb in the 1960s on Rediffusion Malta.jpg|daqsminuri|Kunċert tal-pjanu fuq ir-Rediffusion ta' Malta 1964]] Edmond miet fit-2 ta’ April 2026. https://soundcloud.com/edmondzarb https://www.youtube.com/watch?v=jIA4jYT3zIk&list=RDjIA4jYT3zIk&start_radio=1 https://whoswho.mt/en/his-music-filled-our-lobby-westin-dragonara-pays-its-respects-to-pianist-edmond-zarb https://www.linkedin.com/posts/westin-dragonara-resort_for-over-25-years-edmond-zarbs-music-filled-activity-7447901190119661568-wl9j/ https://www.facebook.com/Westinmalta/photos/for-over-25-years-edmond-zarbs-music-filled-our-lobby-and-touched-the-hearts-of-/1408150994685372/ bgx8db3cf9rdiy0qg1lg4kd7m2fjyy3 0 34447 330115 330091 2026-05-17T14:02:38Z Trigcly 17859 /* Storja */ 330115 wikitext text/x-wiki [[Stampa:Georgians at a feast, by Castelli (3).jpg|daqsminuri|Tpinġija ta' supra tal-Georgia ta' Castelli.]] '''Supra''' (bil-Georgian: სუფრა [supʰɾa]) hija festa tradizzjonali tal-[[Ġeorġja|Georgia]] u hija parti mill-[[kultura]] soċjali tal-pajjiż. Hemm żewġ tipi ta' supra: supra festiva (ლხინის სუფრა, [lxinis supʰra]), imsejħa ''keipi;'' u supra kiebja (ჭირის სუფრა, [tʃʼɪrɪs sʊpʰra]), imsejħa ''kelekhi'', li ssir dejjem wara d-dfin. It-tradizzjonijiet tas-''supra'', bħala parti importanti tal-kultura soċjali tal-Georgia, tniżżlu fil-lista tal-Wirt Kulturali Intanġibbli tal-Georgia fl-2017.<ref>{{Ċita web|url=https://www.culturepartnership.eu/upload/editor/2017/Research/170926%20CDIS%20Georgia%20Analytical%20and%20Technical%20Report.pdf|titlu=UNESCO Culture for development indicators for Georgia (Analytical and Technical Report)}}</ref> == [[Etimoloġija]] == Bil-[[lingwa]] tal-Georgia, "supra" litteralment tfisser "dvalja". Il-kelma ġiet mislufa mill-kelma [[Lingwa Persjana|Persjana]] ''sofre'' (li wkoll tfisser "dvalja"), li min-naħa tagħha ġiet mislufa fil-qedem mill-[[Lingwa Għarbija|Għarbi]] (سفره).<ref>Tuite, K. (2010). "The Autocrat of the Banquet Table: the political and social significance of the Georgian supra". In Vamling, K. (ed.). ''Language, History and Cultural Identities in the Caucasus. Papers from the conference, June 17-19 2005, Malmö University''. [[Malmö]]: Dept. of International Migration and Ethnic Relations, Malmö University. pp. 9–35. ISBN <bdi>978-91-7104-088-6</bdi>.</ref> Il-kelma Persjana ġiet mislufa wkoll bit-[[Lingwa Torka|Tork]] (fost lingwi oħra) bħala ''sofra''.<ref>{{Ċita web|url=https://www.nisanyansozluk.com/kelime/sofra|titlu=sofra|sit=Nişanyan Sözlük|lingwa=tr|data-aċċess=2026-05-17}}</ref> Il-qorti tal-Georgia f'Tiflis (illum il-ġurnata Tbilisi), li kienet tinsab fi ħdan ir-Renju ta' Kartli, kienet tinkorpora parti sostanzjali mill-prattiki ċerimonjali u mit-[[terminoloġija]] mit-tradizzjonijiet [[Safavidi]] matul it-tmexxija ta' żmien is-Safavidi; kien f'din l-epoka storika li t-terminu sab ruħu fil-[[vokabolarju]] tal-lingwa tal-Georgia.<ref>Perry, John R. (1996). "Persian during the Safavid Period: Sketch for an ''Etat de Langue''". In Melville, Charles (ed.). ''Safavid Persia: The History and Politics of an Islamic Society''. I.B. Tauris & Co Ltd. p. 277.</ref> == [[Storja]] == [[Stampa:Pirosmani kutezh.jpg|daqsminuri|''Il-ħbieb ta' Begos'' ta' [[Niko Pirosmani]], [[pittura]] tas-snin 10 tas-seklu 20. Tamada b'<nowiki/>''kantsi'' (qarn) f'idu fil-mument li se jgħolli tazza f'''keipi'' (supra kiebja).]] Filwaqt li l-festini u x-xorb tal-inbid huma ddokumentati fix-xogħlijiet notevoli tal-letteratura tal-qorti tal-Georgia, pereżempju f'''Il-Kavallier bil-Ġilda tal-Pantera'' u ''Amiran-Darejaniani'', kif ukoll fir-rakkonti bikrin tal-ivvjaġġar, it-tradizzjoni li wieħed jgħolli tazza għal xewqat sbieħ bħalma jsir illum il-ġurnata ma kinitx teżisti f'dawk il-perjodi. It-termini bil-Georgian għal "wieħed li jgħolli tazza", jiġifieri ''tamada'' u ''t’olumbaši'', rispettivament ta' oriġini Torka u Ċirkassjana (bit-Tork: ''tulumbaş''), ma jidhrux fir-rekords storiċi qabel is-seklu 19. Barra minn hekk, it-terminu "supra" stess, b'referenza għal bankett, ma kienx għadu tfaċċa, mill-inqas bħala terminu b'referenza għall-festa; fit-[[traduzzjoni]] [[Medjuevu|Medjevali]] bil-Georgian tal-ktieb ta' Ferdowsi ''Shahnameh'' ("Il-Ktieb tar-Rejiet"), supra tirreferi biss għal dvalja jew mejda tal-ikel, u tirrifletti s-sors Persjan tagħha, ''sofre'', fit-test oriġinali. L-espressjonijiet bil-Georgian għal festini fiż-żminijiet pre-Ksaristi huma identifikati bħala ''nadimi'' u ''p’uroba'' (li oriġinat minn ''p’uri'' li tfisser "ħobż", li normalment tintuża b'referenza għal kull tip ta' ikel servut f'ikla). L-istoriku [[John R. Perry]] isostni li l-oriġini tad-drawwa fil-Georgia u tat-terminu "supra" jaf imorru lura għall-influwenza eżerċitata mis-Safavidi tal-[[Iran]]. Il-membri tal-qorti Georgiani tas-shahs Safavidi ġew influwenzati mill-festini tax-xorb tas-Safavidi, imsejħa "sohbat" jew kumpanija, u l-bankett iktar formali, magħruf bħala "sofre", li kien jinkludi ritwal li kien isir mill-mastru taċ-ċerimonji, u b'hekk adattaw dawn l-elementi għall-użu domestiku tagħhom. Il-forma Safavidi tal-festini tax-xorb, ikkaratterizzati minn ritwali, issawret mill-impatt kulturali tan-nomadi tal-isteppi tal-Asja Interna, speċifikament il-popli [[Mongolja|Mongoli]] u Torok.<ref>Perry, John R. (2011). "Cultural currents in the Turco-Persian world of Safavid and post-Safavid times". In Mitchell, Colin P. (ed.). ''New Perspectives on Safavid Iran: Empire and Society''. Routledge. pp. 87–88.</ref> Perry jinnota li filwaqt li s-''sofre'' Iranjana kontemporanja evolviet f'forma iktar ristretta, is-supra tal-Georgia żammet it-tradizzjonijiet tal-Asja Interna fir-reġjun tal-Kawkasu, u b'hekk isservi bħala legat dejjiemi tat-tmexxija Safavida. L-adattament Georgian tal-verżjoni Safavida min-naħa l-oħra jaf influwenzat il-prattika analoga [[Russja|Russa]] li wieħed jgħolli tazza, wara l-annessjoni Russa tal-Georgia.<ref>Perry, John R. (2011). "Cultural currents in the Turco-Persian world of Safavid and post-Safavid times". In Mitchell, Colin P. (ed.). ''New Perspectives on Safavid Iran: Empire and Society''. Routledge. p. 88.</ref> Skont il-filologu [[Levan Bregadze]], l-iżjed okkorrenza bikrija tat-terminu bil-Georgian għal "wieħed li jgħolli tazza", ''sadγegrdzelo'' (li litteralment tfisser "b'xewaqt għal ħajja twila"), jaf tmur lura għal nofs is-seklu 19 f'[[poeżija]] ta' [[Grigol Orbeliani]], ispirata mix-xogħol tal-[[poeta]] Russu [[Vasily Zhukovsky]] wara l-invażjoni tar-Russja min-naħa ta' [[Napuljun I ta' Franza|Napuljun]]. Bregadze jsostni li l-verżjoni kontemporanja tas-supra tal-Georgia ssib l-għeruq tagħha fil-bidu tas-seklu 19, wara l-annessjoni Russa tal-Georgia, u sal-aħħar tas-seklu 19 saret mifruxa mat-territorju kollha li llum il-ġurnata jagħmel parti mill-Georgia. L-ikliet pubbliċi kbar fil-Georgia qatt ma jsiru mingħajr supra; meta ma jkunx hemm imwejjed, is-supra ssir mal-art. == Regoli == [[Stampa:Dinner at Kopala, Tbilisi.jpg|daqsminuri|Mejda kbira lesta għal ''supra'' f'ristorant tal-Georgia fi [[Tbilisi]].]] Ikunu xi jkunu d-daqs u t-tip, supra dejjem titmexxa minn ''tamada'' jew wieħed li jgħolli tazza għal xewqat sbieħ matul il-festa. It-tamada jiġi elett mill-mistednin tal-bankett jew jintgħażel mill-ospitant. Tamada ta' suċċess irid ikollu ħila retorika kbira u jkun kapaċi jikkonsma ammont kbir ta' alkoħol mingħajr ma juri sinjali ta' sakra.<ref>Mühlfried, Florian (2006). ''Postsowjetische Feiern: Das Georgische Bankett im Wandel'' (bil-[[Lingwa Ġermaniża|Ġermaniż]]). Stuttgart: ibidem-Verlag.</ref><ref>Manning, Paul (2012). ''Semiotics of Drink and Drinking''. [[Belt ta' New York|New York]]: Continuum. ISBN <bdi>9781441160188</bdi>.</ref><ref>Muehlfried, Florian (2008). "Sharing the same blood – culture and cuisine in the Republic of Georgia". ''Anthropology of Food'' (S3). doi:10.4000/aof.2342.</ref> Waqt l-ikla, it-tamada jgħolli tazza għal xewqat sbieħ, u mbagħad jitkellem fit-tul dwar xi suġġett marbut max-xewqat sbieħ. Il-mistednin jgħollu t-tazzi tagħhom, iżda ma jixorbux. Wara li t-tamada jkun tkellem, iċ-ċerimonja tkompli, u kulħadd jgħolli tazza ġeneralment fid-direzzjoni kontra l-arloġġ (lejn il-lemin). Il-mistieden li jmiss li jkun jixtieq jitkellem jgħolli t-tazza tiegħu, iżommha ftit fl-għoli, u mbagħad jixrob minnha. Jekk xi mistieden ma jkunx jixtieq jitkellem, dan jista' jixrob mit-tazza tiegħu wara li xi kliem ikun laqtuh b'mod partikolari. Meta wieħed jgħolli tazza għal xewqat sbieħ, ma hemm xejn ħażin li wieħed jibqa' jiekol, iżda t-taħdit imur kontra l-etikett. Ladarba kull min ikun jixtieq jitkellem dwar is-suġġett ikun għamel dan, it-tamada jerġa' jgħolli tazza għal xewqat sbieħ, u ċ-ċiklu jerġa' jibda mill-ġdid. Xi temi tradizzjonali popolari jinkludu xewqat sbieħ dwar [[Alla l-Missier|Alla]], il-Georgia, il-familja, [[Santa Marija|Omm Alla]], diversi qaddisin, il-ħbieb, l-antenati, eċċ. Is-suġġett ta' kull darba li wieħed jgħolli tazza għal xewqat sbieħ jiddependi mit-tamada, li għandu jkun kapaċi jadatta d-diskors tiegħu skont l-okkażjoni. Meta wieħed jgħolli tazza għal xewqat sbieħ f'keipi, jintuża t-terminu ''sadghegrdzelo'' (bil-Georgian: სადღეგრძელო, [sadɣɛɡrdzɛlɔ]), filwaqt li meta wieħed jgħolli tazza għal xewqat sbieħ f'kelekhi, jintuża t-terminu ''shesandobari'' (bil-Georgian: შესანდობარი, [ʃɛsandɔbarɪ]). == Referenzi == [[Kategorija:Tradizzjonijiet]] [[Kategorija:Ġeorġja]] ouaj550hbfkbv5nutwz97w1vl4xflcb 0 34449 330121 2026-05-17T19:13:48Z Trigcly 17859 Kontenut inizjali 330121 wikitext text/x-wiki '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == The word ''fish'' is inherited from Proto-Germanic, and is related to German ''Fisch'', the Latin ''piscis'', and Old Irish ''íasc'', though the exact root is unknown; some authorities reconstruct a Proto-Indo-European root *''peysk-'', attested only in Italic, Celtic, and Germanic. Though often used interchangeably, in biology ''fish'' and ''fishes'' have different meanings. ''Fish'' is used as a singular noun, or as a plural to describe multiple individuals from a single species. ''Fishes'' is used to describe different species or species groups. == Evoluzzjoni == === Storja tal-fossili === About 530 million years ago during the Cambrian explosion, fishlike animals with a notochord and eyes at the front of the body, such as ''Haikouichthys'', appear in the fossil record. During the late Cambrian, other jawless forms such as conodonts appear. Jawed vertebrates appear in the Silurian, with giant armoured placoderms such as ''Dunkleosteus''. Jawed fish, too, appeared during the Silurian: the cartilaginous Chondrichthyes and the bony Osteichthyes. During the Devonian, fish diversity greatly increased, including among the placoderms, lobe-finned fishes, and early sharks, earning the Devonian the epithet "the age of fishes". === Filoġenija === Fishes are a paraphyletic group, since any clade containing all jawed fish (Gnathostomata) or all bony fish (Osteichthyes) also contains the clade of tetrapods (four-limbed vertebrates, mostly terrestrial), which are usually not considered fish. Some tetrapods, such as cetaceans and ichthyosaurs, have secondarily acquired a fish-like body shape through convergent evolution. On the other hand, ''Fishes of the World'' comments that "it is increasingly widely accepted that tetrapods, including ourselves, are simply modified bony fishes, and so we are comfortable with using the taxon Osteichthyes as a clade, which now includes all tetrapods". The biodiversity of extant fish is unevenly distributed among the various groups; teleosts, bony fishes able to protrude their jaws, make up 96% of fish species. The cladogram shows the evolutionary relationships of all groups of living fishes (with their respective diversity) and the tetrapods. Extinct groups are marked with a dagger (†); groups of uncertain placement are labelled with a question mark (?) and dashed lines (- - - - -). Groups with over 25,000 species are in '''boldface'''. {| class="wikitable" |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Cyclostomi (118 species: hagfish, lampreys) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†Thelodonti, †Conodonta, †Anaspida   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Galeaspida |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Osteostraci |- | |- |Jawed | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Placodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†Acanthodii |- | |- | | rowspan="2" | {| class="wikitable" |Chondrichthyes | rowspan="2" |(>1,100 species: sharks, rays, chimaeras) |- | |- |Osteichthyes | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Lobe-finned fish | rowspan="2" | {| class="wikitable" |Actinistia | rowspan="2" |(2 species: coelacanths) |- | |- |Rhipidistia | rowspan="2" | {| class="wikitable" | | rowspan="2" |Dipnoi (6 species: lungfish) |- | |- | | rowspan="2" |'''Tetrapoda''' (>38,000 terrestrial species, not considered fish) |- | |} |- | |} |- | |- |Ray-finned fish | rowspan="2" | {| class="wikitable" |Cladistia | rowspan="2" |(14 species: bichirs, reedfish) |- | |- |Actinopteri | rowspan="2" | {| class="wikitable" |Chondrostei | rowspan="2" |(27 species: sturgeons, paddlefish) |- | |- |Neopterygii | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Holostei | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ginglymodi (7 species: gars, alligator gars) |- | |- | | rowspan="2" |Halecomorphi (2 species: bowfin, eyetail bowfin) |- | |} |- | |- |'''Teleostei''' | rowspan="2" |(>32,000 species) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |vertebrates |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Fishes (without tetrapods) are a paraphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal classifications. Traditional classification divides fish into three extant classes ("Agnatha", Chondrichthyes, and "Osteichthyes"), and with extinct forms sometimes classified within those groups, sometimes as their own classes. Fish account for more than half of vertebrate species. As of 2016, there are over 32,000 described species of bony fish, over 1,100 species of cartilaginous fish, and over 100 hagfish and lampreys. A third of these fall within the nine largest families; from largest to smallest, these are Cyprinidae, Gobiidae, Cichlidae, Characidae, Loricariidae, Balitoridae, Serranidae, Labridae, and Scorpaenidae. About 64 families are monotypic, containing only one species. === Diversità === Fish range in size from the huge 16-metre (52 ft) whale shark to some tiny teleosts only 8-millimetre (0.3 in) long, such as the cyprinid ''Paedocypris progenetica'' and the stout infantfish. Swimming performance varies from fish such as tuna, salmon, and jacks that can cover 10–20 body-lengths per second to species such as eels and rays that swim no more than 0.5 body-lengths per second. A typical fish is cold-blooded, has a streamlined body for rapid swimming, extracts oxygen from water using gills, has two sets of paired fins, one or two dorsal fins, an anal fin and a tail fin, jaws, skin covered with scales, and lays eggs. Each criterion has exceptions, creating a wide diversity in body shape and way of life. For example, some fast-swimming fish are warm-blooded, while some slow-swimming fish have abandoned streamlining in favour of other body shapes. == [[Ekoloġija]] == === Ħabitats === Fish species are roughly divided equally between freshwater and marine (oceanic) ecosystems; there are some 15,200 freshwater species and around 14,800 marine species. Coral reefs in the Indo-Pacific constitute the center of diversity for marine fishes, whereas continental freshwater fishes are most diverse in large river basins of tropical rainforests, especially the Amazon, Congo, and Mekong basins. More than 5,600 fish species inhabit Neotropical freshwaters alone, such that Neotropical fishes represent about 10% of all vertebrate species on the Earth. Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams (e.g., char and gudgeon) to the abyssal and even hadal depths of the deepest oceans (e.g., cusk-eels and snailfish), although none have been found in the deepest 25% of the ocean. The deepest living fish in the ocean so far found is a cusk-eel, ''Abyssobrotula galatheae'', recorded at the bottom of the Puerto Rico Trench at 8,370 m (27,460 ft). In terms of temperature, Jonah's icefish live in cold waters of the Southern Ocean, including under the Filchner–Ronne Ice Shelf at a latitude of 79°S, while desert pupfish live in desert springs, streams, and marshes, sometimes highly saline, with water temperatures as high as 36 C. A few fish live mostly on land or lay their eggs on land near water. Mudskippers feed and interact with one another on mudflats and go underwater to hide in their burrows. A single undescribed species of ''Phreatobius'' has been called a true "land fish" as this worm-like catfish strictly lives among waterlogged leaf litter. Cavefish of multiple families live in underground lakes, underground rivers or aquifers. === Parassiti u predaturi === Like other animals, fish suffer from parasitism. Some species use cleaner fish to remove external parasites. The best known of these are the bluestreak cleaner wrasses of coral reefs in the Indian and Pacific oceans. These small fish maintain cleaning stations where other fish congregate and perform specific movements to attract the attention of the cleaners. Cleaning behaviors have been observed in a number of fish groups, including an interesting case between two cichlids of the same genus, ''Etroplus maculatus'', the cleaner, and the much larger ''E. suratensis''. Fish occupy many trophic levels in freshwater and marine food webs. Fish at the higher levels are predatory, and a substantial part of their prey consists of other fish. In addition, mammals such as dolphins and seals feed on fish, alongside birds such as gannets and cormorants. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == emvd5ineph6cdu2s3kzozt05xxidn8g 330123 330121 2026-05-18T05:19:30Z Trigcly 17859 /* Etimoloġija */ 330123 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Jawed | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |vertebrates |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Fishes (without tetrapods) are a paraphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal classifications. Traditional classification divides fish into three extant classes ("Agnatha", Chondrichthyes, and "Osteichthyes"), and with extinct forms sometimes classified within those groups, sometimes as their own classes. Fish account for more than half of vertebrate species. As of 2016, there are over 32,000 described species of bony fish, over 1,100 species of cartilaginous fish, and over 100 hagfish and lampreys. A third of these fall within the nine largest families; from largest to smallest, these are Cyprinidae, Gobiidae, Cichlidae, Characidae, Loricariidae, Balitoridae, Serranidae, Labridae, and Scorpaenidae. About 64 families are monotypic, containing only one species. === Diversità === Fish range in size from the huge 16-metre (52 ft) whale shark to some tiny teleosts only 8-millimetre (0.3 in) long, such as the cyprinid ''Paedocypris progenetica'' and the stout infantfish. Swimming performance varies from fish such as tuna, salmon, and jacks that can cover 10–20 body-lengths per second to species such as eels and rays that swim no more than 0.5 body-lengths per second. A typical fish is cold-blooded, has a streamlined body for rapid swimming, extracts oxygen from water using gills, has two sets of paired fins, one or two dorsal fins, an anal fin and a tail fin, jaws, skin covered with scales, and lays eggs. Each criterion has exceptions, creating a wide diversity in body shape and way of life. For example, some fast-swimming fish are warm-blooded, while some slow-swimming fish have abandoned streamlining in favour of other body shapes. == [[Ekoloġija]] == === Ħabitats === Fish species are roughly divided equally between freshwater and marine (oceanic) ecosystems; there are some 15,200 freshwater species and around 14,800 marine species. Coral reefs in the Indo-Pacific constitute the center of diversity for marine fishes, whereas continental freshwater fishes are most diverse in large river basins of tropical rainforests, especially the Amazon, Congo, and Mekong basins. More than 5,600 fish species inhabit Neotropical freshwaters alone, such that Neotropical fishes represent about 10% of all vertebrate species on the Earth. Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams (e.g., char and gudgeon) to the abyssal and even hadal depths of the deepest oceans (e.g., cusk-eels and snailfish), although none have been found in the deepest 25% of the ocean. The deepest living fish in the ocean so far found is a cusk-eel, ''Abyssobrotula galatheae'', recorded at the bottom of the Puerto Rico Trench at 8,370 m (27,460 ft). In terms of temperature, Jonah's icefish live in cold waters of the Southern Ocean, including under the Filchner–Ronne Ice Shelf at a latitude of 79°S, while desert pupfish live in desert springs, streams, and marshes, sometimes highly saline, with water temperatures as high as 36 C. A few fish live mostly on land or lay their eggs on land near water. Mudskippers feed and interact with one another on mudflats and go underwater to hide in their burrows. A single undescribed species of ''Phreatobius'' has been called a true "land fish" as this worm-like catfish strictly lives among waterlogged leaf litter. Cavefish of multiple families live in underground lakes, underground rivers or aquifers. === Parassiti u predaturi === Like other animals, fish suffer from parasitism. Some species use cleaner fish to remove external parasites. The best known of these are the bluestreak cleaner wrasses of coral reefs in the Indian and Pacific oceans. These small fish maintain cleaning stations where other fish congregate and perform specific movements to attract the attention of the cleaners. Cleaning behaviors have been observed in a number of fish groups, including an interesting case between two cichlids of the same genus, ''Etroplus maculatus'', the cleaner, and the much larger ''E. suratensis''. Fish occupy many trophic levels in freshwater and marine food webs. Fish at the higher levels are predatory, and a substantial part of their prey consists of other fish. In addition, mammals such as dolphins and seals feed on fish, alongside birds such as gannets and cormorants. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == 9brau8woa8019uawu4ww98kvo0vvg9f 330124 330123 2026-05-18T05:20:34Z Trigcly 17859 /* Filoġenija */ 330124 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Fishes (without tetrapods) are a paraphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal classifications. Traditional classification divides fish into three extant classes ("Agnatha", Chondrichthyes, and "Osteichthyes"), and with extinct forms sometimes classified within those groups, sometimes as their own classes. Fish account for more than half of vertebrate species. As of 2016, there are over 32,000 described species of bony fish, over 1,100 species of cartilaginous fish, and over 100 hagfish and lampreys. A third of these fall within the nine largest families; from largest to smallest, these are Cyprinidae, Gobiidae, Cichlidae, Characidae, Loricariidae, Balitoridae, Serranidae, Labridae, and Scorpaenidae. About 64 families are monotypic, containing only one species. === Diversità === Fish range in size from the huge 16-metre (52 ft) whale shark to some tiny teleosts only 8-millimetre (0.3 in) long, such as the cyprinid ''Paedocypris progenetica'' and the stout infantfish. Swimming performance varies from fish such as tuna, salmon, and jacks that can cover 10–20 body-lengths per second to species such as eels and rays that swim no more than 0.5 body-lengths per second. A typical fish is cold-blooded, has a streamlined body for rapid swimming, extracts oxygen from water using gills, has two sets of paired fins, one or two dorsal fins, an anal fin and a tail fin, jaws, skin covered with scales, and lays eggs. Each criterion has exceptions, creating a wide diversity in body shape and way of life. For example, some fast-swimming fish are warm-blooded, while some slow-swimming fish have abandoned streamlining in favour of other body shapes. == [[Ekoloġija]] == === Ħabitats === Fish species are roughly divided equally between freshwater and marine (oceanic) ecosystems; there are some 15,200 freshwater species and around 14,800 marine species. Coral reefs in the Indo-Pacific constitute the center of diversity for marine fishes, whereas continental freshwater fishes are most diverse in large river basins of tropical rainforests, especially the Amazon, Congo, and Mekong basins. More than 5,600 fish species inhabit Neotropical freshwaters alone, such that Neotropical fishes represent about 10% of all vertebrate species on the Earth. Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams (e.g., char and gudgeon) to the abyssal and even hadal depths of the deepest oceans (e.g., cusk-eels and snailfish), although none have been found in the deepest 25% of the ocean. The deepest living fish in the ocean so far found is a cusk-eel, ''Abyssobrotula galatheae'', recorded at the bottom of the Puerto Rico Trench at 8,370 m (27,460 ft). In terms of temperature, Jonah's icefish live in cold waters of the Southern Ocean, including under the Filchner–Ronne Ice Shelf at a latitude of 79°S, while desert pupfish live in desert springs, streams, and marshes, sometimes highly saline, with water temperatures as high as 36 C. A few fish live mostly on land or lay their eggs on land near water. Mudskippers feed and interact with one another on mudflats and go underwater to hide in their burrows. A single undescribed species of ''Phreatobius'' has been called a true "land fish" as this worm-like catfish strictly lives among waterlogged leaf litter. Cavefish of multiple families live in underground lakes, underground rivers or aquifers. === Parassiti u predaturi === Like other animals, fish suffer from parasitism. Some species use cleaner fish to remove external parasites. The best known of these are the bluestreak cleaner wrasses of coral reefs in the Indian and Pacific oceans. These small fish maintain cleaning stations where other fish congregate and perform specific movements to attract the attention of the cleaners. Cleaning behaviors have been observed in a number of fish groups, including an interesting case between two cichlids of the same genus, ''Etroplus maculatus'', the cleaner, and the much larger ''E. suratensis''. Fish occupy many trophic levels in freshwater and marine food webs. Fish at the higher levels are predatory, and a substantial part of their prey consists of other fish. In addition, mammals such as dolphins and seals feed on fish, alongside birds such as gannets and cormorants. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == 9ogigtcug8s3tohm3y2sbcdumy5xs22 330125 330124 2026-05-18T06:05:23Z Trigcly 17859 /* Tassonomija */ 330125 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == daxn66m4n3j07zm6jjm4z1odmnl8haa 330126 330125 2026-05-18T06:07:15Z Trigcly 17859 added [[Category:Bijoloġija]] using [[Help:Gadget-HotCat|HotCat]] 330126 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == [[Kategorija:Bijoloġija]] h45d3fzec9kpcmu2xt3rdy93a6d0qwy 330127 330126 2026-05-18T06:07:59Z Trigcly 17859 removed [[Category:Bijoloġija]] using [[Help:Gadget-HotCat|HotCat]] 330127 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == daxn66m4n3j07zm6jjm4z1odmnl8haa 330128 330127 2026-05-18T06:08:11Z Trigcly 17859 added [[Category:Klassifikazzjoni xjentifika]] using [[Help:Gadget-HotCat|HotCat]] 330128 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == [[Kategorija:Klassifikazzjoni xjentifika]] rbulb6mw1xlwb8es4xzpzbmci63ur1e 330129 330128 2026-05-18T06:08:18Z Trigcly 17859 added [[Category:Annimali]] using [[Help:Gadget-HotCat|HotCat]] 330129 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets of muscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act as control surfaces like an aircraft's flaps, enabling the fish to steer in any direction. Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called a swim bladder that allows them to adjust their buoyancy by increasing or decreasing the amount of gas it contains. The scales of fish provide protection from predators at the cost of adding stiffness and weight. Fish scales are often highly reflective; this silvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility. === Ċirkolazzjoni === Fish have a closed-loop circulatory system. The heart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart. === Respirazzjoni === ==== Garġi ==== Fish exchange gases using gills on either side of the pharynx. Gills consist of comblike structures called filaments. Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficient countercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover or operculum. They are able to oxygenate their gills using muscles in the head. ==== Teħid tan-nifs ==== Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land. The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water. Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants of rock pools and the intertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily at low tide, and to use their gills when in water. Some coastal fish like rockskippers and mudskippers choose to leave the water to feed in habitats temporarily exposed to the air. Some catfish absorb air through their digestive tracts. === Diġestjoni === The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. An esophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches, pyloric caeca, around the pylorus, of doubtful function. The pancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. The liver produces bile which helps to break up fat into an emulsion which can be absorbed in the intestine. === Eskrezzjoni === Most fish release their nitrogenous wastes as ammonia. This may be excreted through the gills or filtered by the kidneys. Salt is excreted by the rectal gland. Saltwater fish tend to lose water by osmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens in freshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == [[Kategorija:Klassifikazzjoni xjentifika]] [[Kategorija:Annimali]] h4xx6g8codr7bx2qexatzuph6djrcv9 330130 330129 2026-05-18T07:02:07Z Trigcly 17859 /* Ċaqliq */ 330130 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === Il-ġisem ta' ħuta tipika huwa adattat għall-għawm effiċjenti bl-alternanza tal-kontrazzjoni ta' pari ta' muskoli fuq kull naħa tas-sinsla. Dawn il-kontrazzjonijiet jiffurmaw kurvaturi b'għamla tal-ittra S li jiċċaqilqu 'l isfel tul il-ġisem. Malli kull kurvatura tilħaq il-pinna tad-denb, tiġi applikata forza fl-ilma, u l-ħuta tiċċaqlaq 'il quddiem. Il-pinen l-oħra jaġixxu bħala superfiċi tal-kontroll bħall-flaps ta' inġenju tal-ajru, u b'hekk il-ħut ikun jista' jdur fi kwalunkwe direzzjoni. Peress li t-tessuti tal-ġisem huma iktar densi mill-ilma, il-ħut irid jikkumpensa għad-differenza għax inkella jegħreq. Ħafna ħut bl-għadam għandu organu intern imsejjaħ vexxiki tal-għawm li permezz tiegħu jkun jista' jirregola l-kapaċità ta' żamma f'wiċċ l-ilma biż-żieda jew bit-tnaqqis tal-ammont ta' gass li jkun hemm fih. Il-qxur mal-ġilda tal-ħut jipprovdu protezzjoni mill-predaturi minkejja li jżidu r-riġidità u l-piż. Il-qxur mal-ġilda tal-ħut spiss ikunu jirriflettu sew; dan il-[[lewn]] fiddien jipprovdi mimetizzazzjoni fl-oċeani. Peress li l-ilma tal-madwar huwa tal-istess kulur, ir-riflessjoni tal-ilma toffri kważi inviżibbiltà. === Ċirkolazzjoni === Il-ħut għandu sistema ċirkolatorja b'ċiklu magħluq. Il-[[qalb]] tippompja d-demm f'ċiklu uniku mal-ġisem kollu; bħala paragun, il-qalb tal-mammiferi għandha żewġ ċikli, wieħed biex il-pulmuni jiksbu l-ossiġenu, u ieħor biex il-ġisem iqassam l-ossiġenu. Fil-ħut, il-qalb tippompja d-demm permezz tal-garġi. Id-demm rikk bl-ossiġenu mbagħad jiċċirkola mingħajr il-ħtieġa ta' iktar ippompjar, għad-differenza tal-mammiferi, lejn it-tessuti tal-ġisem. Finalment, id-demm bi ftit ossiġenu jirritorna lejn il-qalb. === Respirazzjoni === ==== Garġi ==== Il-ħut jiskambja l-gassijiet permezz tal-garġi fuq kull naħa tal-farinġi. Il-garġi jikkonsistu minn strutturi qishom is-snien ta' moxt imsejħa filamenti. Kull filament fih network kapillari li jipprovdi erja kbira għall-iskambju tal-ossiġenu u tad-[[diossidu tal-karbonju]]. Il-ħut jiskambja l-gassijiet billi jiġbed l-ilma mimli ossiġenu minn ħalqu u jippompjah lejn il-garġi tiegħu. Id-demm kapillari fil-garġi fid-direzzjoni opposta tal-ilma, jirriżulta fi skambju effiċjenti kontra l-kurrent. Il-garġi jimbottaw l-ilma bi ftit ossiġenu 'l barra permezz ta' fetħiet fl-ġnub tal-farinġi. Il-ħut bil-qarquċa jkollu diversi fetħiet tal-garġi: il-klieb il-baħar normalment ikollhom ħames pari u xi kultant ikollhom sitta jew seba' pari; spiss ikollhom jgħumu biex jossiġenaw il-garġi tagħhom. Il-ħut bl-għadam ikollu fetħa waħda tal-garġi fuq kull naħa, li tkun moħbija taħt għata protettiva tal-għadam jew operkulu. Dan il-ħut kapaċi jossiġena l-garġi tiegħu bl-użu tal-muskoli f'rasu. ==== Teħid tan-nifs ==== Xi 400 speċi ta' ħut f'50 familja jista' jieħu n-nifs, u b'hekk jista' jgħix f'ilma bi ftit ossiġenu jew ifeġġ fuq l-art. Il-kapaċità li l-ħut jagħmel dan potenzjalment hija limitata miċ-ċirkolazzjoni b'ċiklu uniku, peress li d-demm ossiġenat mill-organu tat-teħid tan-nifs tagħhom jitħallat mad-demm deossiġenat li jirritorna lejn il-qalb mill-bqija tal-ġisem. Iċ-ċeratodiformi, il-bichirs, il-pixxiħabel, l-amiji, il-pixxisriep u l-pixxisikkina [[Afrika|Afrikani]] evolvew biex inaqqsu dan it-taħlit, u b'hekk inaqqsu t-telf ta' ossiġenu mill-garġi fl-ilma mingħajr wisq ossiġenu. Il-bichirs u ċ-ċetatodiformi għandhom par pulmuni bħal tat-tetrapodi, u b'hekk ikollhom jitilgħu fil-wiċċ biex jieħdu n-nifs. Bosta ħut ieħor, inkluż l-abitanti tal-għadajjar fil-blat u fiż-żona intermareali, jieħu n-nifs meta jrid, peress li kapaċi jieħu n-nifs meta jkun barra mill-ilma, pereżempju kuljum meta l-marea tkun baxxa, u juża l-garġi tiegħu meta jkun fl-ilma. Xi ħut kostali bħall-ballottri tal-ħama u l-perjoftalmi jagħżlu li jitilqu mill-ilma biex imorru jieklu f'ħabitats li jkunu temporanjament esposti għall-arja. Xi pixxigatti jassorbu l-arja mill-apparat diġestiv tagħhom. === Diġestjoni === Is-sistema diġestiva tal-ħut tikkonsisti minn tubu, l-imsaren, mill-ħalq sal-anu. Il-ħalq tal-biċċa l-kbira tal-ħut ikun fih is-snien biex jaħtaf il-priża, jigdem jew iqaċċat il-[[Pjanta|pjanti]] akkwatiċi, jew ikisser l-ikel. Esofagu jġorr l-ikel lejn l-istonku fejn jista' jinħażen u jiġi diġestit parzjalment. Muskolu kostrittur, il-piloru, jeħles l-ikel lejn l-intestini f'intervalli. Ħafna ħut ikollu boroż b'għamla ta' swaba', imsejħa ''caeca'' piloriċi, madwar il-piloru, b'funzjoni dubjuża. Il-frixa tirrilaxxa enżimi fl-intestinti għad-diġestjoni tal-ikel; enżimi oħra jiġu rilaxxati direttament mill-intestinti stess. Il-fwied jipproduċi l-bili biex jgħin fit-tkissir tax-xaħam f'emulsjoni li tkun tista' tiġi assorbita mill-intestini. === Eskrezzjoni === Il-biċċa l-kbira tal-ħut jirrilaxxa l-ħmieġ [[Nitroġenu|nitroġenuż]] tiegħu bħala ammonijaka. Din tiġi rrilaxxata bl-eskrezzjoni permezz tal-garġi jew tiġi ffiltrata mill-kliewi. L-eskrezzjoni tal-melħ issir permezz tal-glandola rektali. Il-ħut tal-baħar għandu t-tendenza li jitlef l-ilma permezz tal-ożmożi; il-kliewi tiegħu jirritorna l-ilma lejn il-ġisem, u jipproduċu awrina kkonċentrata. Dan jiġri bil-kontra fil-ħut tal-ilma ħelu: dan għandu t-tendenza li jikseb l-ilma bl-ożmożi, u jipproduċi awrina dilwita. Xi ħut għandu kliewi li kapaċi joperaw kemm fl-ilma ħelu kif ukoll fl-ilma baħar. === Moħħ === Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal. However, some fish have relatively large brains, notably mormyrids and sharks, which have brains about as large for their body weight as birds and marsupials. At the front of the brain are the olfactory lobes, a pair of structures that receive and process signals from the nostrils via the two olfactory nerves. Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is the telencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is the diencephalon; it works with hormones and homeostasis. The pineal body is just above the diencephalon; it detects light, maintains circadian rhythms, and controls color changes. The midbrain contains the two optic lobes. These are very large in species that hunt by sight, such as rainbow trout and cichlids. The hindbrain controls swimming and balance. The single-lobed cerebellum is the biggest part of the brain; it is small in hagfish and lampreys, but very large in mormyrids, processing their electrical sense. The brain stem or myelencephalon controls some muscles and body organs, and governs respiration and osmoregulation. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == [[Kategorija:Klassifikazzjoni xjentifika]] [[Kategorija:Annimali]] dq5ghw66bft0bx58di3n7kn9104ekvp 330131 330130 2026-05-18T08:13:52Z Trigcly 17859 /* Moħħ */ 330131 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === Il-ġisem ta' ħuta tipika huwa adattat għall-għawm effiċjenti bl-alternanza tal-kontrazzjoni ta' pari ta' muskoli fuq kull naħa tas-sinsla. Dawn il-kontrazzjonijiet jiffurmaw kurvaturi b'għamla tal-ittra S li jiċċaqilqu 'l isfel tul il-ġisem. Malli kull kurvatura tilħaq il-pinna tad-denb, tiġi applikata forza fl-ilma, u l-ħuta tiċċaqlaq 'il quddiem. Il-pinen l-oħra jaġixxu bħala superfiċi tal-kontroll bħall-flaps ta' inġenju tal-ajru, u b'hekk il-ħut ikun jista' jdur fi kwalunkwe direzzjoni. Peress li t-tessuti tal-ġisem huma iktar densi mill-ilma, il-ħut irid jikkumpensa għad-differenza għax inkella jegħreq. Ħafna ħut bl-għadam għandu organu intern imsejjaħ vexxiki tal-għawm li permezz tiegħu jkun jista' jirregola l-kapaċità ta' żamma f'wiċċ l-ilma biż-żieda jew bit-tnaqqis tal-ammont ta' gass li jkun hemm fih. Il-qxur mal-ġilda tal-ħut jipprovdu protezzjoni mill-predaturi minkejja li jżidu r-riġidità u l-piż. Il-qxur mal-ġilda tal-ħut spiss ikunu jirriflettu sew; dan il-[[lewn]] fiddien jipprovdi mimetizzazzjoni fl-oċeani. Peress li l-ilma tal-madwar huwa tal-istess kulur, ir-riflessjoni tal-ilma toffri kważi inviżibbiltà. === Ċirkolazzjoni === Il-ħut għandu sistema ċirkolatorja b'ċiklu magħluq. Il-[[qalb]] tippompja d-demm f'ċiklu uniku mal-ġisem kollu; bħala paragun, il-qalb tal-mammiferi għandha żewġ ċikli, wieħed biex il-pulmuni jiksbu l-ossiġenu, u ieħor biex il-ġisem iqassam l-ossiġenu. Fil-ħut, il-qalb tippompja d-demm permezz tal-garġi. Id-demm rikk bl-ossiġenu mbagħad jiċċirkola mingħajr il-ħtieġa ta' iktar ippompjar, għad-differenza tal-mammiferi, lejn it-tessuti tal-ġisem. Finalment, id-demm bi ftit ossiġenu jirritorna lejn il-qalb. === Respirazzjoni === ==== Garġi ==== Il-ħut jiskambja l-gassijiet permezz tal-garġi fuq kull naħa tal-farinġi. Il-garġi jikkonsistu minn strutturi qishom is-snien ta' moxt imsejħa filamenti. Kull filament fih network kapillari li jipprovdi erja kbira għall-iskambju tal-ossiġenu u tad-[[diossidu tal-karbonju]]. Il-ħut jiskambja l-gassijiet billi jiġbed l-ilma mimli ossiġenu minn ħalqu u jippompjah lejn il-garġi tiegħu. Id-demm kapillari fil-garġi fid-direzzjoni opposta tal-ilma, jirriżulta fi skambju effiċjenti kontra l-kurrent. Il-garġi jimbottaw l-ilma bi ftit ossiġenu 'l barra permezz ta' fetħiet fl-ġnub tal-farinġi. Il-ħut bil-qarquċa jkollu diversi fetħiet tal-garġi: il-klieb il-baħar normalment ikollhom ħames pari u xi kultant ikollhom sitta jew seba' pari; spiss ikollhom jgħumu biex jossiġenaw il-garġi tagħhom. Il-ħut bl-għadam ikollu fetħa waħda tal-garġi fuq kull naħa, li tkun moħbija taħt għata protettiva tal-għadam jew operkulu. Dan il-ħut kapaċi jossiġena l-garġi tiegħu bl-użu tal-muskoli f'rasu. ==== Teħid tan-nifs ==== Xi 400 speċi ta' ħut f'50 familja jista' jieħu n-nifs, u b'hekk jista' jgħix f'ilma bi ftit ossiġenu jew ifeġġ fuq l-art. Il-kapaċità li l-ħut jagħmel dan potenzjalment hija limitata miċ-ċirkolazzjoni b'ċiklu uniku, peress li d-demm ossiġenat mill-organu tat-teħid tan-nifs tagħhom jitħallat mad-demm deossiġenat li jirritorna lejn il-qalb mill-bqija tal-ġisem. Iċ-ċeratodiformi, il-bichirs, il-pixxiħabel, l-amiji, il-pixxisriep u l-pixxisikkina [[Afrika|Afrikani]] evolvew biex inaqqsu dan it-taħlit, u b'hekk inaqqsu t-telf ta' ossiġenu mill-garġi fl-ilma mingħajr wisq ossiġenu. Il-bichirs u ċ-ċetatodiformi għandhom par pulmuni bħal tat-tetrapodi, u b'hekk ikollhom jitilgħu fil-wiċċ biex jieħdu n-nifs. Bosta ħut ieħor, inkluż l-abitanti tal-għadajjar fil-blat u fiż-żona intermareali, jieħu n-nifs meta jrid, peress li kapaċi jieħu n-nifs meta jkun barra mill-ilma, pereżempju kuljum meta l-marea tkun baxxa, u juża l-garġi tiegħu meta jkun fl-ilma. Xi ħut kostali bħall-ballottri tal-ħama u l-perjoftalmi jagħżlu li jitilqu mill-ilma biex imorru jieklu f'ħabitats li jkunu temporanjament esposti għall-arja. Xi pixxigatti jassorbu l-arja mill-apparat diġestiv tagħhom. === Diġestjoni === Is-sistema diġestiva tal-ħut tikkonsisti minn tubu, l-imsaren, mill-ħalq sal-anu. Il-ħalq tal-biċċa l-kbira tal-ħut ikun fih is-snien biex jaħtaf il-priża, jigdem jew iqaċċat il-[[Pjanta|pjanti]] akkwatiċi, jew ikisser l-ikel. Esofagu jġorr l-ikel lejn l-istonku fejn jista' jinħażen u jiġi diġestit parzjalment. Muskolu kostrittur, il-piloru, jeħles l-ikel lejn l-intestini f'intervalli. Ħafna ħut ikollu boroż b'għamla ta' swaba', imsejħa ''caeca'' piloriċi, madwar il-piloru, b'funzjoni dubjuża. Il-frixa tirrilaxxa enżimi fl-intestinti għad-diġestjoni tal-ikel; enżimi oħra jiġu rilaxxati direttament mill-intestinti stess. Il-fwied jipproduċi l-bili biex jgħin fit-tkissir tax-xaħam f'emulsjoni li tkun tista' tiġi assorbita mill-intestini. === Eskrezzjoni === Il-biċċa l-kbira tal-ħut jirrilaxxa l-ħmieġ [[Nitroġenu|nitroġenuż]] tiegħu bħala ammonijaka. Din tiġi rrilaxxata bl-eskrezzjoni permezz tal-garġi jew tiġi ffiltrata mill-kliewi. L-eskrezzjoni tal-melħ issir permezz tal-glandola rektali. Il-ħut tal-baħar għandu t-tendenza li jitlef l-ilma permezz tal-ożmożi; il-kliewi tiegħu jirritorna l-ilma lejn il-ġisem, u jipproduċu awrina kkonċentrata. Dan jiġri bil-kontra fil-ħut tal-ilma ħelu: dan għandu t-tendenza li jikseb l-ilma bl-ożmożi, u jipproduċi awrina dilwita. Xi ħut għandu kliewi li kapaċi joperaw kemm fl-ilma ħelu kif ukoll fl-ilma baħar. === Moħħ === Il-ħut għandu moħħ żgħir meta mqabbel mad-daqs tal-ġisem u ma' vertebrati oħra, tipikament 0.07 % tal-massa tal-moħħ ta' għasfur jew mammiferu b'daqs simili. Madankollu, xi speċijiet ta' ħut għandhom moħħ relattivament kbir, b'mod partikolari l-mormiridi u l-klieb il-baħar, li għandhomm moħħ kbir kważi daqs il-piż ta' ġisimhom bħall-għasafar u l-marsupjali. Fuq in-naħa ta' quddiem tal-moħħ għandhom lobi tax-xamm, par strutturi li jirċievu u jipproċessaw is-sinjali minn kull minħar permezz taż-żewġ nervituri tax-xamm. Il-ħut li jikkaċċja primarjament permezz tax-xamm, bħall-missini u l-klieb il-baħar, ikollu lobi tax-xamm kbar ħafna. Warajhom ikun hemm it-telenċefalu, li fil-ħut għandu x'jaqsam l-iktar max-xamm. Kollha f'daqqa dawn l-istrutturi jiffurmaw in-naħa ta' quddiem tal-moħħ. Id-diċenċefalu jikkollega n-naħa ta' quddiem tal-moħħ man-naħa tan-nofs; dan jaħdem bl-ormoni u bl-omeostażi. Il-korp pineali jinsab eżatt fuq id-dienċenfalu; dan jieħu ħsieb id-detezzjoni tad-dawl, iż-żamma tar-ritmi ċirkadjani u l-kontroll tat-tibdil tal-kuluri. In-naħa tan-nofs tal-moħħ fiha żewġ lobi ottiċi. Dawn ikunu kbar ħafna fl-ispeċijiet li jikkaċċjaw bil-vista, bħaċ-ċiklidi u t-trota qawsalla. In-naħa ta' wara tal-moħħ jikkontrolla l-għawm u l-bilanċ. Iċ-ċerebellum jew iċ-ċervellett b'lobu uniku huwa l-ikbar parti tal-moħħ; dan ikun żgħir fil-missini u fil-qlafat, iżda jkun kbir ħafna fil-mormiridi, u jipproċessa s-sens elettriku tagħhom. Iz-zokk enċefaliku jew il-mielenċefalu jikkontrolla xi muskoli u organi tal-ġisem, u jirregola r-respirazzjoni u l-ożmoregolazzjoni. === Sistemi sensorji === The lateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey. This can be considered both a sense of touch and of hearing. Blind cave fish navigate almost entirely through the sensations from their lateral line system. Some fish, such as catfish and sharks, have the ampullae of Lorenzini, electroreceptors that detect weak electric currents on the order of millivolt. Vision is an important sensory system in fish. Fish eyes are similar to those of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Their retinas generally have both rods and cones (for scotopic and photopic vision); many species have colour vision, often with three types of cone. Teleosts can see polarized light; some such as cyprinids have a fourth type of cone that detects ultraviolet. Amongst jawless fish, the lamprey has well-developed eyes, while the hagfish has only primitive eyespots. Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines and otoliths in their ears, inside their heads. Some can detect sound through the swim bladder. Some fish, including salmon, are capable of magnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field. The mechanism of fish magnetoreception remains unknown; experiments in birds imply a quantum radical pair mechanism. === Konjizzjoni === The cognitive capacities of fish include self-awareness, as seen in mirror tests. Manta rays and wrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement. ''Choerodon'' wrasse, archerfish, and Atlantic cod can solve problems and invent tools. The monogamous cichlid ''Amatitlania siquia'' exhibits pessimistic behavior when prevented from being with its partner. Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination. Behavioral research suggests that fish are sentient, capable of experiencing pain. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Deuterostomes | rowspan="2" | {| class="wikitable" | | rowspan="2" |Echinoderms, hemichordates, cephalochordates, urochordates |- | |- |Vertebrates | rowspan="2" | {| class="wikitable" | | rowspan="2" |Jawless fishes |- |'''VLR adaptive immunity''' |- | | rowspan="2" |Jawed fishes and tetrapods |- |'''V(D)J adaptive immunity''' |} |- | |} |- |'''innate immunity''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == [[Kategorija:Klassifikazzjoni xjentifika]] [[Kategorija:Annimali]] 019pnulr51h3g21zy8200snyaggyytr 330132 330131 2026-05-18T08:37:03Z Trigcly 17859 /* Difiżi kontra l-mard */ 330132 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === Il-ġisem ta' ħuta tipika huwa adattat għall-għawm effiċjenti bl-alternanza tal-kontrazzjoni ta' pari ta' muskoli fuq kull naħa tas-sinsla. Dawn il-kontrazzjonijiet jiffurmaw kurvaturi b'għamla tal-ittra S li jiċċaqilqu 'l isfel tul il-ġisem. Malli kull kurvatura tilħaq il-pinna tad-denb, tiġi applikata forza fl-ilma, u l-ħuta tiċċaqlaq 'il quddiem. Il-pinen l-oħra jaġixxu bħala superfiċi tal-kontroll bħall-flaps ta' inġenju tal-ajru, u b'hekk il-ħut ikun jista' jdur fi kwalunkwe direzzjoni. Peress li t-tessuti tal-ġisem huma iktar densi mill-ilma, il-ħut irid jikkumpensa għad-differenza għax inkella jegħreq. Ħafna ħut bl-għadam għandu organu intern imsejjaħ vexxiki tal-għawm li permezz tiegħu jkun jista' jirregola l-kapaċità ta' żamma f'wiċċ l-ilma biż-żieda jew bit-tnaqqis tal-ammont ta' gass li jkun hemm fih. Il-qxur mal-ġilda tal-ħut jipprovdu protezzjoni mill-predaturi minkejja li jżidu r-riġidità u l-piż. Il-qxur mal-ġilda tal-ħut spiss ikunu jirriflettu sew; dan il-[[lewn]] fiddien jipprovdi mimetizzazzjoni fl-oċeani. Peress li l-ilma tal-madwar huwa tal-istess kulur, ir-riflessjoni tal-ilma toffri kważi inviżibbiltà. === Ċirkolazzjoni === Il-ħut għandu sistema ċirkolatorja b'ċiklu magħluq. Il-[[qalb]] tippompja d-demm f'ċiklu uniku mal-ġisem kollu; bħala paragun, il-qalb tal-mammiferi għandha żewġ ċikli, wieħed biex il-pulmuni jiksbu l-ossiġenu, u ieħor biex il-ġisem iqassam l-ossiġenu. Fil-ħut, il-qalb tippompja d-demm permezz tal-garġi. Id-demm rikk bl-ossiġenu mbagħad jiċċirkola mingħajr il-ħtieġa ta' iktar ippompjar, għad-differenza tal-mammiferi, lejn it-tessuti tal-ġisem. Finalment, id-demm bi ftit ossiġenu jirritorna lejn il-qalb. === Respirazzjoni === ==== Garġi ==== Il-ħut jiskambja l-gassijiet permezz tal-garġi fuq kull naħa tal-farinġi. Il-garġi jikkonsistu minn strutturi qishom is-snien ta' moxt imsejħa filamenti. Kull filament fih network kapillari li jipprovdi erja kbira għall-iskambju tal-ossiġenu u tad-[[diossidu tal-karbonju]]. Il-ħut jiskambja l-gassijiet billi jiġbed l-ilma mimli ossiġenu minn ħalqu u jippompjah lejn il-garġi tiegħu. Id-demm kapillari fil-garġi fid-direzzjoni opposta tal-ilma, jirriżulta fi skambju effiċjenti kontra l-kurrent. Il-garġi jimbottaw l-ilma bi ftit ossiġenu 'l barra permezz ta' fetħiet fl-ġnub tal-farinġi. Il-ħut bil-qarquċa jkollu diversi fetħiet tal-garġi: il-klieb il-baħar normalment ikollhom ħames pari u xi kultant ikollhom sitta jew seba' pari; spiss ikollhom jgħumu biex jossiġenaw il-garġi tagħhom. Il-ħut bl-għadam ikollu fetħa waħda tal-garġi fuq kull naħa, li tkun moħbija taħt għata protettiva tal-għadam jew operkulu. Dan il-ħut kapaċi jossiġena l-garġi tiegħu bl-użu tal-muskoli f'rasu. ==== Teħid tan-nifs ==== Xi 400 speċi ta' ħut f'50 familja jista' jieħu n-nifs, u b'hekk jista' jgħix f'ilma bi ftit ossiġenu jew ifeġġ fuq l-art. Il-kapaċità li l-ħut jagħmel dan potenzjalment hija limitata miċ-ċirkolazzjoni b'ċiklu uniku, peress li d-demm ossiġenat mill-organu tat-teħid tan-nifs tagħhom jitħallat mad-demm deossiġenat li jirritorna lejn il-qalb mill-bqija tal-ġisem. Iċ-ċeratodiformi, il-bichirs, il-pixxiħabel, l-amiji, il-pixxisriep u l-pixxisikkina [[Afrika|Afrikani]] evolvew biex inaqqsu dan it-taħlit, u b'hekk inaqqsu t-telf ta' ossiġenu mill-garġi fl-ilma mingħajr wisq ossiġenu. Il-bichirs u ċ-ċetatodiformi għandhom par pulmuni bħal tat-tetrapodi, u b'hekk ikollhom jitilgħu fil-wiċċ biex jieħdu n-nifs. Bosta ħut ieħor, inkluż l-abitanti tal-għadajjar fil-blat u fiż-żona intermareali, jieħu n-nifs meta jrid, peress li kapaċi jieħu n-nifs meta jkun barra mill-ilma, pereżempju kuljum meta l-marea tkun baxxa, u juża l-garġi tiegħu meta jkun fl-ilma. Xi ħut kostali bħall-ballottri tal-ħama u l-perjoftalmi jagħżlu li jitilqu mill-ilma biex imorru jieklu f'ħabitats li jkunu temporanjament esposti għall-arja. Xi pixxigatt jassorbi l-arja mill-apparat diġestiv tiegħu. === Diġestjoni === Is-sistema diġestiva tal-ħut tikkonsisti minn tubu, l-imsaren, mill-ħalq sal-anu. Il-ħalq tal-biċċa l-kbira tal-ħut ikun fih is-snien biex jaħtaf il-priża, jigdem jew iqaċċat il-[[Pjanta|pjanti]] akkwatiċi, jew ikisser l-ikel. Esofagu jġorr l-ikel lejn l-istonku fejn jista' jinħażen u jiġi diġestit parzjalment. Muskolu kostrittur, il-piloru, jeħles l-ikel lejn l-intestini f'intervalli. Ħafna ħut ikollu boroż b'għamla ta' swaba', imsejħa ''caeca'' piloriċi, madwar il-piloru, b'funzjoni dubjuża. Il-frixa tirrilaxxa enżimi fl-intestinti għad-diġestjoni tal-ikel; enżimi oħra jiġu rilaxxati direttament mill-intestinti stess. Il-fwied jipproduċi l-bili biex jgħin fit-tkissir tax-xaħam f'emulsjoni li tkun tista' tiġi assorbita mill-intestini. === Eskrezzjoni === Il-biċċa l-kbira tal-ħut jirrilaxxa l-ħmieġ [[Nitroġenu|nitroġenuż]] tiegħu bħala ammonijaka. Din tiġi rrilaxxata bl-eskrezzjoni permezz tal-garġi jew tiġi ffiltrata mill-kliewi. L-eskrezzjoni tal-melħ issir permezz tal-glandola rektali. Il-ħut tal-baħar għandu t-tendenza li jitlef l-ilma permezz tal-ożmożi; il-kliewi tiegħu jirritorna l-ilma lejn il-ġisem, u jipproduċu awrina kkonċentrata. Dan jiġri bil-kontra fil-ħut tal-ilma ħelu: dan għandu t-tendenza li jikseb l-ilma bl-ożmożi, u jipproduċi awrina dilwita. Xi ħut għandu kliewi li kapaċi joperaw kemm fl-ilma ħelu kif ukoll fl-ilma baħar. === Moħħ === Il-ħut għandu moħħ żgħir meta mqabbel mad-daqs tal-ġisem u ma' vertebrati oħra, tipikament 0.07 % tal-massa tal-moħħ ta' għasfur jew mammiferu b'daqs simili. Madankollu, xi speċijiet ta' ħut għandhom moħħ relattivament kbir, b'mod partikolari l-mormiridi u l-klieb il-baħar, li għandhomm moħħ kbir kważi daqs il-piż ta' ġisimhom bħall-għasafar u l-marsupjali. Fuq in-naħa ta' quddiem tal-moħħ għandhom lobi tax-xamm, par strutturi li jirċievu u jipproċessaw is-sinjali minn kull minħar permezz taż-żewġ nervituri tax-xamm. Il-ħut li jikkaċċja primarjament permezz tax-xamm, bħall-missini u l-klieb il-baħar, ikollu lobi tax-xamm kbar ħafna. Warajhom ikun hemm it-telenċefalu, li fil-ħut għandu x'jaqsam l-iktar max-xamm. Kollha f'daqqa dawn l-istrutturi jiffurmaw in-naħa ta' quddiem tal-moħħ. Id-diċenċefalu jikkollega n-naħa ta' quddiem tal-moħħ man-naħa tan-nofs; dan jaħdem bl-ormoni u bl-omeostażi. Il-korp pineali jinsab eżatt fuq id-dienċenfalu; dan jieħu ħsieb id-detezzjoni tad-dawl, iż-żamma tar-ritmi ċirkadjani u l-kontroll tat-tibdil tal-kuluri. In-naħa tan-nofs tal-moħħ fiha żewġ lobi ottiċi. Dawn ikunu kbar ħafna fl-ispeċijiet li jikkaċċjaw bil-vista, bħaċ-ċiklidi u t-trota qawsalla. In-naħa ta' wara tal-moħħ jikkontrolla l-għawm u l-bilanċ. Iċ-ċerebellum jew iċ-ċervellett b'lobu uniku huwa l-ikbar parti tal-moħħ; dan ikun żgħir fil-missini u fil-qlafat, iżda jkun kbir ħafna fil-mormiridi, u jipproċessa s-sens elettriku tagħhom. Iz-zokk enċefaliku jew il-mielenċefalu jikkontrolla xi muskoli u organi tal-ġisem, u jirregola r-respirazzjoni u l-ożmoregolazzjoni. === Sistemi sensorji === Is-sistema tal-linja laterali hija network ta' sensuri fil-ġilda meħtieġa għad-detezzjoni tal-iċken kurrenti u vibrazzjonijiet, u għad-detezzjoni taċ-ċaqliq tal-ħut tal-madwar, kemm jekk ikunu predaturi kif ukoll jekk ikunu priża. Din tista' titqies kemm bħala sens ta' mess kif ukoll ta' smigħ. Il-ħut għami tal-għerien jiċċaqilqu kważi għalkollox permezz tas-sensazzjonijiet mis-sistema tal-linja laterali tagħhom. Xi ħut, bħall-pixxigatt u l-klieb il-baħar, għandhom l-ampulli ta' Lorenzini, li huma elettroriċetturi għad-detezzjoni tal-kurrenti elettriċi dgħajfin fil-livell ta' millivolt. Il-vista hija sistema sensorja importanti fil-ħut. L-għajnejn tal-ħut huma simili għal dawk tal-vertebrati terrestri bħall-għasafar u l-mammiferi, iżda jkollhom lenti iktar sferika. Ir-retini tagħhom ġeneralment ikollhom kemm vireg kif ukoll koni (għall-vista skotopika u fotopika); bosta speċijiet li għandhom vista bil-kulur, spiss ikollhom tliet tipi ta' koni. It-teleosti jistgħu jaraw id-dawl polarizzat; xi ħut bħaċ-ċiprinidi għandhom ir-raba' tip ta' kon għad-detezzjoni tar-raġġi ultravjola. Fost il-ħut mingħajr xedaq, il-qlafat għandhom għajnejn żviluppati sew, filwaqt li l-missini għandhom għajnejn primittivi biss. Is-smigħ ukoll huwa sistema sensorja importanti fil-ħut. Il-ħut jisimgħu l-ħsejjes billi jużaw il-linji laterali u l-otoliti f'widnejhom, fi ħdan rashom. Xi speċijiet jistgħu jisimgħu l-ħsejjes permezz tal-vexxiki tal-għawm. Xi speċijiet ta' ħut, inkluż is-salamun, għandhom il-kapaċità tal-manjetoriċezzjoni; meta l-assi ta' kamp manjetiku jinbidel madwar tank ċirkolari ta' ħut li jkun għadu qed jikber, dan jerġa' jorjenta ruħu skont il-kamp. Il-mekkaniżmu tal-manjetoriċezzjoni fil-ħut għadu mhux magħruf; xi esperimenti fl-għasafar jimplikaw mekkaniżmu tal-par radikali kwantistiku. === Konjizzjoni === Il-ħiliet konjittivi tal-ħut jinkludu l-kapaċità li jkun konxju tiegħu nnifsu, kif wieħed jista' jara fit-testijiet bil-mirja. Ir-rajja manta u l-għarajjes li jitpoġġew quddiem mera, kemm-il darba jaraw jekk l-imġiba tar-riflessjoni tagħhom hijiex l-istess bħaċ-ċaqliq ta' ġisimhom. It-tirdi ''Choerodon'', il-pixxiarċieri u l-merluzz tal-[[Oċean Atlantiku|Atlantiku]] kapaċi jsolvu l-problemi u jivvintaw l-għodod. Iċ-ċiklid monogamu ''Amatitlania siquia'' juri mġiba pessimistika meta ma jitħalliex f'par. Il-ħut jorjenta ruħu bl-użu ta' għeliem; jaf juża mapep mentali bbażati fuq diversi għeliem. Il-ħut kapaċi jitgħallem isib triqtu fil-labirinti, u b'hekk dan juri li għandu memorja spazjali u diskriminazzjoni viżiva. Ir-riċerka komportamentali tissuġġerixxi li l-ħut iħoss u kapaċi jesperjenza l-uġigħ. === Elettroġenesi === Electric fish such as elephantfishes, the African knifefish, and electric eels have some of their muscles adapted to generate electric fields. They use the field to locate and identify objects such as prey in the waters around them, which may be turbid or dark. Strongly electric fish like the electric eel can in addition use their electric organs to generate shocks powerful enough to stun their prey. === Endotermija === Most fish are exclusively cold-blooded or ectothermic. However, the Scombroidei are warm-blooded (endothermic), including the billfishes and tunas. The opah, a lampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss. Among the cartilaginous fishes, sharks of the families Lamnidae (such as the great white shark) and Alopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to the bluefin tuna and the porbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Dewterostomi | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ekinodermi, emikordati, ċefalokordati, urokordati |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ħut mingħajr xedaq |- |'''immunità adattiva VLR''' |- | | rowspan="2" |Ħut bix-xedaq u tetrapodi |- |'''immunità adattiva V(D)J''' |} |- | |} |- |'''immunità innata''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == [[Kategorija:Klassifikazzjoni xjentifika]] [[Kategorija:Annimali]] 2jt5mmq7lnabu8zdt0kcdmthxf8xxpi 330133 330132 2026-05-18T08:58:38Z Trigcly 17859 /* Elettroġenesi */ 330133 wikitext text/x-wiki [[Stampa:Coryphaena hippurus.png|daqsminuri|Il-mahi-mahi, ''Coryphaena hippurus''.]] '''Ħuta''' hija [[annimal]] vertebrat akkwatiku, anamnijotiku u bil-garġi bi kranju iebes biex jipproteġi l-moħħ, iżda mingħajr riġlejn bis-swaba'. Il-ħut jista' jiġi raggruppat f'ħut mingħajr xedaq iktar tal-qiegħ u ħut bix-xedaq iktar komuni, u dan tal-aħħar jinkludi l-ħut kartilaġinuż u bl-għadam ħaj kollu, kif ukoll il-plakodermi u l-akantodjani estinti. Għad-differenza tat-tradizzjoni twila tar-raggruppament tal-ħut kollu fi [[Klassi (bijoloġija)|klassi]] unika (''Pisces''), il-filoġenetika moderna tħares lejn il-ħut bħala grupp parafiletiku li jinkludi l-vertebrati kollha għajr it-tetrapodi. Bil-[[Lingwa Maltija|Malti]], il-plural ta' ħuta huwa ħut kemm b'referenza għal għadd ta' ħut individwali kif ukoll b'referenza għal għadd ta' [[Speċi|speċijiet]] ta' ħut. Il-biċċa l-kbira tal-ħut għandu [[Demm|demmu]] biered u t-temperatura ta' ġismu tvarja skont l-ilma ta' madwaru, għalkemm xi ħut kbir u attiv, bħall-kelb il-baħar abjad u t-tonn jista' jibqa' jkollu temperatura ogħla tal-ġisem. Ħafna ħut jista' jikkomunika b'mod akustiku ma' ħut ieħor, pereżempju waqt in-namra. L-istudju tal-ħut jissejjaħ ittjoloġija. Jeżistu iktar minn 33,000 speċi ta' ħut li għadu jeżisti, u b'hekk huwa faċilment l-ikbar grupp ta' vertebrati u iktar mill-ispeċijiet kollha tal-klassijiet tradizzjonali l-oħra, jiġifieri l-[[Anfibju|anfibji]], ir-[[Rettilu|rettili]], l-[[Għasfur|għasafar]] u l-[[Mammiferu|mammiferi]], f'daqqa. Il-biċċa l-kbira tal-ħut jagħmel parti mill-klassi tal-attinotterigi jew tal-''Actinopterygii'', il-ħut tal-pinen mirfuda minn raġġi, li jirrappreżenta madwar nofs il-vertebrati ħajjin kollha. L-iżjed ħut bikri tfaċċa matul il-perjodu Kambrijan bħala wikkiela filtraturi żgħar; dawn komplew jevolvu matul il-perjodu Paleożojku, u ddiversifikaw f'bosta forom. L-iżjed ħut bikri b'garġi respiratorji apposta u par pinen, l-ostrakodermi, kellhom pjanċi tal-għadam tqal li kienu jservu bħala eżoskeletri protettivi kontra l-predaturi invertebrati. L-ewwel ħut bix-xedaq, il-plakodermi, tfaċċaw fil-perjodu Silurjan u ddiversifikaw ferm matul il-perjodu Devonjan, l-"Epoka tal-Ħut". Il-ħut bl-għadam, distint mill-preżenza ta' vexxiki tal-għawm u iktar 'il quddiem mill-preżenza ta' endoskeletri bl-għadam, feġġ bħala l-grupp dominanti ta' ħut wara li l-estinzjoni tal-aħħar tal-perjodu Devonjan qerdet il-predaturi ewlenin, il-plakodermi. Il-ħut bl-għadam huwa maqsum iktar f'ħut bil-pinen bil-lobi u l-ħut bil-pinen mirfuda minn raġġi. Madwar 96 % tal-ispeċijiet kollha tal-ħut ħaj huma teleosti, jiġifieri grupp ewlieni ta' ħut bil-pinen mirfuda minn raġġi li jistgħu jestendu x-xedaq tagħhom. It-tetrapodi, fil-biċċa l-kbira grupp monofiletiku terrestri ta' vertebrati li ddominaw l-ogħla livelli trofiċi fl-ekosistemi akkwatiċi u terrestri mill-perjodu Paleożojku Aħħari, evolvew mill-ħut bil-pinen bil-lobi matul il-perjodu Karboniferu, u żviluppaw [[Pulmun|pulmuni]] għat-teħid tan-nifs omologi għall-vexxiki tal-għawm. Il-ħut ilu riżorsa naturali importanti għall-[[bniedem]] miż-żminijiet [[Preistorja|preistoriċi]], speċjalment bħala ikel. Is-[[Sajjied|sajjieda]] kummerċjali u tas-sussistenza jaqbdu l-ħut permezz tas-sajd jew irabbuh f'għadajjar jew f'gaġeġ tat-tnissil fl-oċean. Il-ħut jinqabad għar-rikreazzjoni jew jitrabba minn dawk li jrabbu l-ħut bħala ornamenti għall-wiri privat u pubbliku f'akkwarji u f'vaski fil-ġonna. Il-ħut kellu rwol fil-[[kultura]] umana tul is-sekli u serva bħala divinitajiet, simboli [[Reliġjon|reliġjużi]] u bħala s-suġġetti tal-[[L-Arti|arti]], tal-kotba u tal-films. == [[Etimoloġija]] == Isem il-klassi ''Pisces'' ġej mil-Latin ''piscis'', mill-Proto-[[Lingwi Ġermaniċi|Ġermaniku]] ''fish'' relatat mal-[[Lingwa Ġermaniża|Ġermaniż]] ''Fisch'' u mal-[[Lingwa Irlandiża|Irlandiż]] Antik ''íasc'', għalkemm l-għerq preċiż mhux magħruf; xi awtoritajiet jagħmlu rikostruzzjoni ta' għerq Proto-Indo-[[Ewropa|Ewropew]] *''peysk-'', li huwa attestat biss fil-lingwi Italiċi, Ċeltiċi u Ġermaniċi. == [[Evoluzzjoni]] == === [[Storja]] tal-fossili === Madwar 530 miljun sena ilu waqt l-isplużjoni tal-perjodu Kambrijan, fir-rekords tal-fossili tfaċċaw annimali qishom ħut b'notokord u bl-għajnejn fin-naħa ta' quddiem tal-ġisem, bħall-''Haikouichthys''. Matul l-aħħar tal-perjodu Kambrijan tfaċċaw ukoll forom oħra ta' ħut mingħajr xedaq bħall-konodonti. Il-vertebrati bix-xedaq tfaċċaw fil-perjodu Silurjan, bi plakodermi ġganteski bl-armatura bħad-''Dunkleosteus''. Il-ħut bix-xedaq ukoll tfaċċa fil-perjodu Silurjan: il-''Chondrichthyes'' bil-qarquċa u l-''Osteichthyes'' bl-għadam. Matul il-perjodu Devonjan, id-diversità tal-ħut żdiedet sew, inkluż fost il-plakodermi, il-ħut bil-pinen bil-lobi u l-klieb il-baħar bikrin, u b'hekk il-perjodu Devonjan tlaqqam bħala "l-Epoka tal-Ħut". === Filoġenija === Il-ħut huwa grupp parafiletiku, peress li kwalunkwe grupp monofiletiku li jinkludi l-ħut kollu bix-xedaq (''Gnathostomata'') jew il-ħut kollu bl-għadam (''Osteichthyes'') fih ukoll il-grupp monofiletiku tat-tetrapodi (vertebrati b'erba' riġlejn, l-iktar terrestri), li normalment ma jitqisux bħala ħut. Xi tetrapodi, bħaċ-ċetaċji u l-ittjosawri, sekondarjament kisbu għamla tal-ġisem qisha tal-ħut permezz tal-evoluzzjoni konverġenti. Min-naħa l-oħra, ''Fishes of the World'' tikkummenta li "kulma jmur huwa iktar aċċettat b'mod wiesa' li t-tetrapodi, inkluż aħna stess, huma sempliċement ħut bl-għadam immodifikat, għaldaqstant ninsabu komdi li nużaw it-[[takson]] ''Osteichthyes'' bħala grupp monofiletiku, li issa jinkludi t-tetrapodi kollha". Il-[[bijodiversità]] tal-ħut eżistenti mhix mifruxa b'mod uniformi fost id-diversi gruppi; it-teleosti, il-ħut bl-għadam li kapaċi jestendi x-xedaq tiegħu, jirrappreżentaw sa 96 % tal-ispeċijiet tal-ħut. It-tabella ta' hawn taħt turi r-relazzjonijiet evoluzzjonarji tal-gruppi kollha tal-ħut ħaj (bid-diversità rispettiva tiegħu) u tat-tetrapodi. Il-gruppi estinti huma mmarkati b'salib (†); il-gruppi b'kollokazzjoni inċerta huma mmarkati b'punt interrogattiv (?) u bis-singijiet (- - - - -). Il-gruppi b'iktar minn 25,000 speċi huma mmarkati b'tipa grassa. {| class="wikitable" |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ċiklostomi (118-il speċi: missini u qlafat) |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Thelodonti'', †''Conodonta'', †''Anaspida''   |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Galeaspida'' |- | |- | | rowspan="2" | {| class="wikitable" | | rowspan="2" |†''Osteostraci'' |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |†Plakodermi |- | |- | | rowspan="2" | {| class="wikitable" |? | rowspan="2" |†''Acanthodii'' |- | |- | | rowspan="2" | {| class="wikitable" |''Chondrichthyes'' | rowspan="2" |(>1,100 speċi: klieb il-baħar, rajja, kimeri) |- | |- |''Osteichthyes'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |Ħut bil-pinen bil-lobi | rowspan="2" | {| class="wikitable" |''Actinistia'' | rowspan="2" |(2 speċijiet: ċelakanti) |- | |- |''Rhipidistia'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Dipnoi'' (6 speċijiet: ċeratodiformi) |- | |- | | rowspan="2" |'''''Tetrapoda''''' (>38,000 speċi terrestri, li ma jitqisux bħala ħut) |- | |} |- | |} |- | |- |Ħut bil-pinen mirfuda bir-raġġi | rowspan="2" | {| class="wikitable" |''Cladistia'' | rowspan="2" |(14-il speċi: bichirs) |- | |- |''Actinopteri'' | rowspan="2" | {| class="wikitable" |''Chondrostei'' | rowspan="2" |(27 speċi: sturjuni, pixxipaletti) |- | |- |''Neopterygii'' | rowspan="2" | {| class="wikitable" | | rowspan="2" | {| class="wikitable" |''Holostei'' | rowspan="2" | {| class="wikitable" | | rowspan="2" |''Ginglymodi'' (7 speċijiet: imsell) |- | |- | | rowspan="2" |''Halecomorphi'' (2 speċijiet: amija) |- | |} |- | |- |'''''Teleostei''''' | rowspan="2" |(>32,000 speċi) |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- | |} |- |bix-xedaq |} |- | |} |- | |} |- | |} |- | |} === Tassonomija === Il-ħut (mingħajr it-tetrapodi) huwa grupp parafiletiku u għal din ir-raġuni, il-klassi ''Pisces'' li ġieli tidher f'xogħlijiet referenzjarji iktar antiki ma għadhiex tintuża fil-klassifikazzjonijiet formali. Il-klassifikazzjoni tradizzjonali taqsam il-ħut fi tliet klassijiet eżistenti (''Agnatha'', ''Chondrichthyes'' u ''Osteichthyes''), u xi kultant b'forom estinti kklassifikati fi ħdan dawk il-gruppi bħala l-klassijiet tagħhom stess. Il-ħut jirrappreżenta iktar minn nofs l-ispeċijiet vertebrati. Sal-2016 kien hemm iktar minn 32,000 speċi deskritta ta' ħut bl-għadam, iktar minn 1,100 speċi ta' ħut bil-qarquċa, u iktar minn 100 missina u qalfat. Terz minn dawn jagħmlu parti mill-ikbar disa' [[Familja (bijoloġija)|familji]]; mill-ikbar għall-iżgħar, dawn huma ''Cyprinidae'', ''Gobiidae'', ''Cichlidae'', ''Characidae'', ''Loricariidae'', ''Balitoridae'', ''Serranidae'', ''Labridae'' u ''Scorpaenidae''. Madwar 64 familja huma monotipiċi u fihom speċi waħda biss. === Diversità === Id-daqs tal-ħut ivarja mill-kelb il-baħar baliena enormi ta' 16-il metru (52 pied) għal teleosti twal 8 millimetri (0.3 pulzieri) biss, bħaċ-ċiprinid ''Paedocypris progenetica'' u l-''Gobiidae'' ''Schindleria brevipinguis''. Il-prestazzjoni tal-għawm tvarja minn ħut bħat-tonn, is-salamun u l-luċċju li jistgħu jkopru 10–20 darba t-tul ta' ġisimhom kull sekonda, għal speċijiet bħas-sallura u r-rajja li jgħumu b'mhux iktar minn nofs it-tul ta' ġisimhom kull sekonda. Il-ħut tipiku jkollu demmu biered, ikollu ġisem razzjonalizzat għall-għawm rapidu, jieħu l-[[ossiġenu]] mill-ilma permezz tal-garġi, ikollu żewġ pari pinen, pinna dorsali waħda jew tnejn, pinna anali u pinna tad-denb, xedaq, il-ġilda miksija bil-qxur, u jbid il-bajd. Kull kriterju fih eċċezzjonijiet, u b'hekk dan joħloq diversità wiesgħa ta' għamliet tal-ġisem u ta' stili ta' għajxien. Pereżempju, xi ħut li jgħum b'mod rapidu għandu demmu sħun, filwaqt li xi ħut li jgħum bil-mod abbanduna r-razzjonalizzazzjoni tal-ġisem favur għamliet oħra tal-ġisem. == [[Ekoloġija]] == === Ħabitats === L-ispeċijiet tal-ħut huma bejn wieħed u ieħor maqsumin b'mod indaqs bejn l-ekosistemi tal-ilma ħelu u l-ekosistemi tal-baħar (oċeaniċi); hemm xi 15,200 speċi tal-ilma ħelu u madwar 14,800 speċi tal-baħar. L-iskolli tal-qroll fl-Indo-Paċifiku jikkostitwixxu ċ-ċentru tad-diversità għall-ħut tal-baħar, filwaqt li l-ħut tal-ilma ħelu kontinentali għandhom l-ikbar diversità fil-baċiri tax-xmajjar il-kbar tal-foresti pluvjali tropikali, speċjalment il-baċiri tal-Amażonja, tal-Kongo u tal-Mekong. Iktar minn 5,600 speċi ta' ħut jgħixu fl-ilma ħelu Neotropikali biss, u b'hekk il-ħut Neotropikali jirrappreżenta madwar 10 % tal-ispeċijiet vertebrati kollha fid-[[Id-Dinja|Dinja]]. Il-ħut huwa abbundanti fil-biċċa l-kbira tal-korpi tal-ilma. Jista' jinstab f'kważi l-[[Ambjent (bijoloġija)|ambjenti]] akkwatiċi kollha, minn nixxigħat għoljin fil-muntanji (eż. salvelini u gobbjuni) sal-fond abissali tal-iżjed oċeani fondi (eż. sallura tal-qiegħ u ħut li jgħix fil-qxur), għalkemm l-ebda ħut ma nstab fl-iżjed 25 % fondi tal-oċeani. Il-ħut ħaj li jgħix l-iktar fil-fond fl-oċeani sa issa huwa s-sallura tal-qiegħ, ''Abyssobrotula galatheae'', li ġiet irreġistrata fil-qiegħ tat-Trunċiera ta' [[Puerto Rico]] f'fond ta' 8,370 [[metru]] (27,460 pied). F'termini ta' temperatura, il-ħut tas-silġ ta' Jonah jgħix fl-ilmijiet kesħin tal-Oċean tan-Nofsinhar, inkluż taħt ix-Xatt tas-Silġ ta' Filchner–Ronne f'latitudni ta' 79°S, filwaqt li l-pupazzi tad-deżert jgħixu fil-fawwariet tad-deżert, fin-nixxigħat u fl-imraġ, xi kultant b'kontenut għoli ta' melħ u b'temperaturi għoljin sa 36 °C. Ftit ħut jgħix l-iktar fuq l-art jew ibid il-bajd tiegħu fuq l-art qrib l-ilma. Il-perjoftalmi jieklu u jinteraġixxu ma' xulxin fl-artijiet imtajna ċatti u jinżlu taħt l-ilma biex jistaħbew fil-moħbiet tagħhom. Speċi unika mhux deskritta ta' ''Phreatobius'' ġiet imsejħa "ħuta tal-art" reali peress li dan il-pixxigatt qisu dudu jgħix rigorożament qalb il-weraq imxarrab bl-ilma. Il-ħut tal-għerien ta' diversi familji jgħix fil-lagi ta' taħt l-art, fix-xmajjar ta' taħt l-art jew fl-akwifers. === Parassiti u predaturi === Bħall-annimali l-oħra, il-ħut ibati mill-parassitiżmu. Xi speċijiet jużaw pixxinaddafa biex ineħħu l-parassiti esterni. L-iżjed magħrufa fosthom huma l-pixxinaddafa tal-faxx blu tal-iskolli tal-qroll fl-[[Oċean Indjan]] u fl-[[Oċean Paċifiku]]. Dan il-ħut żgħir inaddaf fejn jinġema' ħut ieħor u jagħmel ċaqliq speċifiku biex jiġbed l-attenzjoni tal-pixxinaddafa. L-imġiba tat-tindif ġiet osservata f'għadd ta' gruppi tal-ħut, inkluż każ interessanti bejn żewġ ċiklidi tal-istess [[Ġeneru (tassonomija)|ġeneru]], l-''Etroplus maculatus'', il-pixxinaddaf, u l-''E. suratensis'' ferm akbar. Il-ħut jokkupa bosta livelli trofiċi fil-katina tal-ikel tal-ilma ħelu u tal-baħar. Il-ħut fil-livelli l-iktar għoljin huwa predatorju, u parti sostanzjali tal-priża tiegħu jikkonsisti minn ħut ieħor. Barra minn hekk, il-mammiferi bħad-dniefel u l-foki jieklu l-ħut, flimkien mal-għasafar bħas-suli u l-marguni. == [[Anatomija]] u fiżjoloġija == === Ċaqliq === Il-ġisem ta' ħuta tipika huwa adattat għall-għawm effiċjenti bl-alternanza tal-kontrazzjoni ta' pari ta' muskoli fuq kull naħa tas-sinsla. Dawn il-kontrazzjonijiet jiffurmaw kurvaturi b'għamla tal-ittra S li jiċċaqilqu 'l isfel tul il-ġisem. Malli kull kurvatura tilħaq il-pinna tad-denb, tiġi applikata forza fl-ilma, u l-ħuta tiċċaqlaq 'il quddiem. Il-pinen l-oħra jaġixxu bħala superfiċi tal-kontroll bħall-flaps ta' inġenju tal-ajru, u b'hekk il-ħut ikun jista' jdur fi kwalunkwe direzzjoni. Peress li t-tessuti tal-ġisem huma iktar densi mill-ilma, il-ħut irid jikkumpensa għad-differenza għax inkella jegħreq. Ħafna ħut bl-għadam għandu organu intern imsejjaħ vexxiki tal-għawm li permezz tiegħu jkun jista' jirregola l-kapaċità ta' żamma f'wiċċ l-ilma biż-żieda jew bit-tnaqqis tal-ammont ta' gass li jkun hemm fih. Il-qxur mal-ġilda tal-ħut jipprovdu protezzjoni mill-predaturi minkejja li jżidu r-riġidità u l-piż. Il-qxur mal-ġilda tal-ħut spiss ikunu jirriflettu sew; dan il-[[lewn]] fiddien jipprovdi mimetizzazzjoni fl-oċeani. Peress li l-ilma tal-madwar huwa tal-istess kulur, ir-riflessjoni tal-ilma toffri kważi inviżibbiltà. === Ċirkolazzjoni === Il-ħut għandu sistema ċirkolatorja b'ċiklu magħluq. Il-[[qalb]] tippompja d-demm f'ċiklu uniku mal-ġisem kollu; bħala paragun, il-qalb tal-mammiferi għandha żewġ ċikli, wieħed biex il-pulmuni jiksbu l-ossiġenu, u ieħor biex il-ġisem iqassam l-ossiġenu. Fil-ħut, il-qalb tippompja d-demm permezz tal-garġi. Id-demm rikk bl-ossiġenu mbagħad jiċċirkola mingħajr il-ħtieġa ta' iktar ippompjar, għad-differenza tal-mammiferi, lejn it-tessuti tal-ġisem. Finalment, id-demm bi ftit ossiġenu jirritorna lejn il-qalb. === Respirazzjoni === ==== Garġi ==== Il-ħut jiskambja l-gassijiet permezz tal-garġi fuq kull naħa tal-farinġi. Il-garġi jikkonsistu minn strutturi qishom is-snien ta' moxt imsejħa filamenti. Kull filament fih network kapillari li jipprovdi erja kbira għall-iskambju tal-ossiġenu u tad-[[diossidu tal-karbonju]]. Il-ħut jiskambja l-gassijiet billi jiġbed l-ilma mimli ossiġenu minn ħalqu u jippompjah lejn il-garġi tiegħu. Id-demm kapillari fil-garġi fid-direzzjoni opposta tal-ilma, jirriżulta fi skambju effiċjenti kontra l-kurrent. Il-garġi jimbottaw l-ilma bi ftit ossiġenu 'l barra permezz ta' fetħiet fl-ġnub tal-farinġi. Il-ħut bil-qarquċa jkollu diversi fetħiet tal-garġi: il-klieb il-baħar normalment ikollhom ħames pari u xi kultant ikollhom sitta jew seba' pari; spiss ikollhom jgħumu biex jossiġenaw il-garġi tagħhom. Il-ħut bl-għadam ikollu fetħa waħda tal-garġi fuq kull naħa, li tkun moħbija taħt għata protettiva tal-għadam jew operkulu. Dan il-ħut kapaċi jossiġena l-garġi tiegħu bl-użu tal-muskoli f'rasu. ==== Teħid tan-nifs ==== Xi 400 speċi ta' ħut f'50 familja jista' jieħu n-nifs, u b'hekk jista' jgħix f'ilma bi ftit ossiġenu jew ifeġġ fuq l-art. Il-kapaċità li l-ħut jagħmel dan potenzjalment hija limitata miċ-ċirkolazzjoni b'ċiklu uniku, peress li d-demm ossiġenat mill-organu tat-teħid tan-nifs tagħhom jitħallat mad-demm deossiġenat li jirritorna lejn il-qalb mill-bqija tal-ġisem. Iċ-ċeratodiformi, il-bichirs, il-pixxiħabel, l-amiji, il-pixxisriep u l-pixxisikkina [[Afrika|Afrikani]] evolvew biex inaqqsu dan it-taħlit, u b'hekk inaqqsu t-telf ta' ossiġenu mill-garġi fl-ilma mingħajr wisq ossiġenu. Il-bichirs u ċ-ċetatodiformi għandhom par pulmuni bħal tat-tetrapodi, u b'hekk ikollhom jitilgħu fil-wiċċ biex jieħdu n-nifs. Bosta ħut ieħor, inkluż l-abitanti tal-għadajjar fil-blat u fiż-żona intermareali, jieħu n-nifs meta jrid, peress li kapaċi jieħu n-nifs meta jkun barra mill-ilma, pereżempju kuljum meta l-marea tkun baxxa, u juża l-garġi tiegħu meta jkun fl-ilma. Xi ħut kostali bħall-ballottri tal-ħama u l-perjoftalmi jagħżlu li jitilqu mill-ilma biex imorru jieklu f'ħabitats li jkunu temporanjament esposti għall-arja. Xi pixxigatt jassorbi l-arja mill-apparat diġestiv tiegħu. === Diġestjoni === Is-sistema diġestiva tal-ħut tikkonsisti minn tubu, l-imsaren, mill-ħalq sal-anu. Il-ħalq tal-biċċa l-kbira tal-ħut ikun fih is-snien biex jaħtaf il-priża, jigdem jew iqaċċat il-[[Pjanta|pjanti]] akkwatiċi, jew ikisser l-ikel. Esofagu jġorr l-ikel lejn l-istonku fejn jista' jinħażen u jiġi diġestit parzjalment. Muskolu kostrittur, il-piloru, jeħles l-ikel lejn l-intestini f'intervalli. Ħafna ħut ikollu boroż b'għamla ta' swaba', imsejħa ''caeca'' piloriċi, madwar il-piloru, b'funzjoni dubjuża. Il-frixa tirrilaxxa enżimi fl-intestinti għad-diġestjoni tal-ikel; enżimi oħra jiġu rilaxxati direttament mill-intestinti stess. Il-fwied jipproduċi l-bili biex jgħin fit-tkissir tax-xaħam f'emulsjoni li tkun tista' tiġi assorbita mill-intestini. === Eskrezzjoni === Il-biċċa l-kbira tal-ħut jirrilaxxa l-ħmieġ [[Nitroġenu|nitroġenuż]] tiegħu bħala ammonijaka. Din tiġi rrilaxxata bl-eskrezzjoni permezz tal-garġi jew tiġi ffiltrata mill-kliewi. L-eskrezzjoni tal-melħ issir permezz tal-glandola rektali. Il-ħut tal-baħar għandu t-tendenza li jitlef l-ilma permezz tal-ożmożi; il-kliewi tiegħu jirritorna l-ilma lejn il-ġisem, u jipproduċu awrina kkonċentrata. Dan jiġri bil-kontra fil-ħut tal-ilma ħelu: dan għandu t-tendenza li jikseb l-ilma bl-ożmożi, u jipproduċi awrina dilwita. Xi ħut għandu kliewi li kapaċi joperaw kemm fl-ilma ħelu kif ukoll fl-ilma baħar. === Moħħ === Il-ħut għandu moħħ żgħir meta mqabbel mad-daqs tal-ġisem u ma' vertebrati oħra, tipikament 0.07 % tal-massa tal-moħħ ta' għasfur jew mammiferu b'daqs simili. Madankollu, xi speċijiet ta' ħut għandhom moħħ relattivament kbir, b'mod partikolari l-mormiridi u l-klieb il-baħar, li għandhomm moħħ kbir kważi daqs il-piż ta' ġisimhom bħall-għasafar u l-marsupjali. Fuq in-naħa ta' quddiem tal-moħħ għandhom lobi tax-xamm, par strutturi li jirċievu u jipproċessaw is-sinjali minn kull minħar permezz taż-żewġ nervituri tax-xamm. Il-ħut li jikkaċċja primarjament permezz tax-xamm, bħall-missini u l-klieb il-baħar, ikollu lobi tax-xamm kbar ħafna. Warajhom ikun hemm it-telenċefalu, li fil-ħut għandu x'jaqsam l-iktar max-xamm. Kollha f'daqqa dawn l-istrutturi jiffurmaw in-naħa ta' quddiem tal-moħħ. Id-diċenċefalu jikkollega n-naħa ta' quddiem tal-moħħ man-naħa tan-nofs; dan jaħdem bl-ormoni u bl-omeostażi. Il-korp pineali jinsab eżatt fuq id-dienċenfalu; dan jieħu ħsieb id-detezzjoni tad-dawl, iż-żamma tar-ritmi ċirkadjani u l-kontroll tat-tibdil tal-kuluri. In-naħa tan-nofs tal-moħħ fiha żewġ lobi ottiċi. Dawn ikunu kbar ħafna fl-ispeċijiet li jikkaċċjaw bil-vista, bħaċ-ċiklidi u t-trota qawsalla. In-naħa ta' wara tal-moħħ jikkontrolla l-għawm u l-bilanċ. Iċ-ċerebellum jew iċ-ċervellett b'lobu uniku huwa l-ikbar parti tal-moħħ; dan ikun żgħir fil-missini u fil-qlafat, iżda jkun kbir ħafna fil-mormiridi, u jipproċessa s-sens elettriku tagħhom. Iz-zokk enċefaliku jew il-mielenċefalu jikkontrolla xi muskoli u organi tal-ġisem, u jirregola r-respirazzjoni u l-ożmoregolazzjoni. === Sistemi sensorji === Is-sistema tal-linja laterali hija network ta' sensuri fil-ġilda meħtieġa għad-detezzjoni tal-iċken kurrenti u vibrazzjonijiet, u għad-detezzjoni taċ-ċaqliq tal-ħut tal-madwar, kemm jekk ikunu predaturi kif ukoll jekk ikunu priża. Din tista' titqies kemm bħala sens ta' mess kif ukoll ta' smigħ. Il-ħut għami tal-għerien jiċċaqilqu kważi għalkollox permezz tas-sensazzjonijiet mis-sistema tal-linja laterali tagħhom. Xi ħut, bħall-pixxigatt u l-klieb il-baħar, għandhom l-ampulli ta' Lorenzini, li huma elettroriċetturi għad-detezzjoni tal-kurrenti elettriċi dgħajfin fil-livell ta' millivolt. Il-vista hija sistema sensorja importanti fil-ħut. L-għajnejn tal-ħut huma simili għal dawk tal-vertebrati terrestri bħall-għasafar u l-mammiferi, iżda jkollhom lenti iktar sferika. Ir-retini tagħhom ġeneralment ikollhom kemm vireg kif ukoll koni (għall-vista skotopika u fotopika); bosta speċijiet li għandhom vista bil-kulur, spiss ikollhom tliet tipi ta' koni. It-teleosti jistgħu jaraw id-dawl polarizzat; xi ħut bħaċ-ċiprinidi għandhom ir-raba' tip ta' kon għad-detezzjoni tar-raġġi ultravjola. Fost il-ħut mingħajr xedaq, il-qlafat għandhom għajnejn żviluppati sew, filwaqt li l-missini għandhom għajnejn primittivi biss. Is-smigħ ukoll huwa sistema sensorja importanti fil-ħut. Il-ħut jisimgħu l-ħsejjes billi jużaw il-linji laterali u l-otoliti f'widnejhom, fi ħdan rashom. Xi speċijiet jistgħu jisimgħu l-ħsejjes permezz tal-vexxiki tal-għawm. Xi speċijiet ta' ħut, inkluż is-salamun, għandhom il-kapaċità tal-manjetoriċezzjoni; meta l-assi ta' kamp manjetiku jinbidel madwar tank ċirkolari ta' ħut li jkun għadu qed jikber, dan jerġa' jorjenta ruħu skont il-kamp. Il-mekkaniżmu tal-manjetoriċezzjoni fil-ħut għadu mhux magħruf; xi esperimenti fl-għasafar jimplikaw mekkaniżmu tal-par radikali kwantistiku. === Konjizzjoni === Il-ħiliet konjittivi tal-ħut jinkludu l-kapaċità li jkun konxju tiegħu nnifsu, kif wieħed jista' jara fit-testijiet bil-mirja. Ir-rajja manta u l-għarajjes li jitpoġġew quddiem mera, kemm-il darba jaraw jekk l-imġiba tar-riflessjoni tagħhom hijiex l-istess bħaċ-ċaqliq ta' ġisimhom. It-tirdi ''Choerodon'', il-pixxiarċieri u l-merluzz tal-[[Oċean Atlantiku|Atlantiku]] kapaċi jsolvu l-problemi u jivvintaw l-għodod. Iċ-ċiklid monogamu ''Amatitlania siquia'' juri mġiba pessimistika meta ma jitħalliex f'par. Il-ħut jorjenta ruħu bl-użu ta' għeliem; jaf juża mapep mentali bbażati fuq diversi għeliem. Il-ħut kapaċi jitgħallem isib triqtu fil-labirinti, u b'hekk dan juri li għandu memorja spazjali u diskriminazzjoni viżiva. Ir-riċerka komportamentali tissuġġerixxi li l-ħut iħoss u kapaċi jesperjenza l-uġigħ. === Elettroġenesi === Il-ħut elettriku bħall-pixxiiljunfanti, il-pixxisikkina Afrikan u s-sallura elettrika għandhom uħud mill-muskoli tagħhom adattati għall-ġenerazzjoni tal-kampi elettriċi. Dawn jużaw il-kamp biex isibu u jidentifikaw il-priża fl-ilmijiet ta' madwarhom, li jaf ikunu mdardrin jew mudlama. Barra minn hekk, il-ħut elettriku ħafna bħas-sallura elettrika jista' juża l-organi elettriċi tiegħu biex jiġġenera xokkijiet tant qawwijin li "jipparalizzaw" il-priża tagħhom. === Endotermija === Il-biċċa l-kbira tal-ħut huwa esklużivament demmu biered jew ektotermiku. Madankollu, l-i''Scombroidei'' għandhom demmhom sħun (endotermiċi), inkluż il-marlin u t-tonn. Il-pixxiqamar, tip ta' lampriform, juża l-endotermija f'ġismu kollu, u jiġġenera s-sħana bil-muskoli tal-għawm tiegħu biex isaħħan ġismu, filwaqt li l-iskambju kontra l-kurrent inaqqas it-telf tas-sħana. Fost il-ħut bil-qarquċa, il-klieb il-baħar tal-familji ''Lamnidae'' (bħall-kelb il-baħar abjad) u ''Alopiidae'' (il-pixxivolpi) huma endotermiċi. Il-livell ta' endotermija jvarja mill-marlin, li jsaħħan l-għajnejn u l-moħħ biss, għat-tonn tal-pinna blu u l-pixxiplamtu, li jżommu temperatura tal-ġisem ta' iktar minn 20 °C (68 °F) 'il fuq mill-ilma ta' madwarhom. === Riproduzzjoni u ċiklu tal-ħajja === The primary reproductive organs are paired testicles and ovaries. Eggs are released from the ovary to the oviducts. Over 97% of fish, including salmon and goldfish, are oviparous, meaning that the eggs are shed into the water and develop outside the mother's body. The eggs are usually fertilized outside the mother's body, with the male and female fish shedding their gametes into the surrounding water. In a few oviparous fish, such as the skates, fertilization is internal: the male uses an intromittent organ to deliver sperm into the female's genital opening of the female. Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish are planktonic larvae. They have a large yolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow and change in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding on zooplankton prey. Some fish such as surf-perches, splitfins, and lemon sharks are viviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to the placenta to connect the mother's blood supply with the embryo's. === Tiswija tad-DNA === Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that may damage their DNA, such as pollutants, UV light and reactive oxygen species. To deal with such DNA damages, a variety of different DNA repair pathways are employed by fish embryos during their development. In recent years zebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage. === Difiżi kontra l-mard === Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by the epidermis that traps and inhibits the growth of microorganisms. If pathogens breach these defenses, the innate immune system can mount an inflammatory response that increases blood flow to the infected region and delivers white blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such as proteins on the surfaces of pathogenic bacteria, recognised by the adaptive immune system. Immune systems evolved in deuterostomes as shown in the cladogram. {| class="wikitable" |Dewterostomi | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ekinodermi, emikordati, ċefalokordati, urokordati |- | |- |Vertebrati | rowspan="2" | {| class="wikitable" | | rowspan="2" |Ħut mingħajr xedaq |- |'''immunità adattiva VLR''' |- | | rowspan="2" |Ħut bix-xedaq u tetrapodi |- |'''immunità adattiva V(D)J''' |} |- | |} |- |'''immunità innata''' |} Immune organs vary by type of fish. The jawless fish have lymphoid tissue within the anterior kidney, and granulocytes in the gut. They have their own type of adaptive immune system; it makes use of variable lymphocyte receptors (VLR) to generate immunity to a wide range of antigens, The result is much like that of jawed fishes and tetrapods, but it may have evolved separately. All jawed fishes have an adaptive immune system with B and T lymphocytes bearing immunoglobulins and T cell receptors respectively. This makes use of Variable–Diversity–Joining rearrangement (V(D)J) to create immunity to a wide range of antigens. This system evolved once and is basal to the jawed vertebrate clade. Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads, Leydig's organ within the esophagus, and a spiral valve in their intestine, while their thymus and spleen have similar functions to those of the same organs in the immune systems of tetrapods. Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs. == Imġiba == === Ġliba ħut === A ''shoal'' is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. A ''school'' is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction. Schooling is sometimes an antipredator adaptation, offering improved vigilance against predators. It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn. The capelin migrates annually in large schools between its feeding areas and its spawning grounds. === Komunikazzjoni === Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship. The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder. Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. In ''Haemulon flavolineatum'', the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds. The longsnout seahorse, ''Hippocampus reidi'' produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium. Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when the ''H. reidi'' are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations. Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations. Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder. Female and male toadfishes emit short-duration grunts, often as a fright response. In addition to short-duration grunts, male toadfishes produce "boat whistle calls". These calls are longer in duration, lower in frequency, and are primarily used to attract mates. The various sounds have frequency range of 140 Hz to 260 Hz. The frequencies of the calls depend on the rate at which the sonic muscles contract. The red drum, ''Sciaenops ocellatus'', produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz. ''S. ocellatus'' produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles. == Konservazzjoni == The 2025 IUCN Red List names 2,367 fish species that are endangered or critically endangered. Included are species such as Atlantic cod, Devil's Hole pupfish, coelacanths, and great white sharks. Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool. === Sajd eċċessiv === The Food and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished". Overfishing is a major threat to edible fish such as cod and tuna. Overfishing eventually causes fish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of the Pacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968. In the case of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992. Fisheries scientists and the fishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it. On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years. === Theddidiet oħra === A key stress on both freshwater and marine ecosystems is habitat degradation including water pollution, the building of dams, removal of water for use by humans, and the introduction of exotic species including predators. Freshwater fish, especially if endemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes. River dams, especially major schemes like the Kariba Dam (Zambezi river) and the Aswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch. Industrial bottom trawling can damage seabed habitats, as has occurred on the Georges Bank in the North Atlantic. Introduction of aquatic invasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them; the arrival of a comb jelly in the Black Sea damaged the anchovy fishery there. The opening of the Suez Canal in 1869 made possible Lessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in the Mediterranean Sea, deeply impacting its overall biodiversity and ecology. The predatory Nile perch was deliberately introduced to Lake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500 endemic species of cichlid fish. It drastically altered the lake's ecology, and simplified the fishery from multi-species to just three: the Nile perch, the silver cyprinid, and another introduced fish, the Nile tilapia. The haplochromine cichlid populations have collapsed. == Importanza għall-bnedmin == === Ekonomija === Throughout history, humans have used fish as a food source for dietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China, is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish. Fishing is a large global business which provides income for millions of people. As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020, anchoveta represented 4.9 Mt, Alaska pollock 3.5 Mt, skipjack tuna 2.8 Mt, and Atlantic herring and yellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt. === Rikreazzjoni === Fish have been recognized as a source of beauty for almost as long as used for food, appearing in cave art, being raised as ornamental fish in ponds, and displayed in aquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, or artisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs a rod, reel, line, hooks, and a wide range of baits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species. === Kultura === Fish themes have symbolic significance in many religions. In ancient Mesopotamia, fish offerings were made to the gods from the very earliest times. Fish were also a major symbol of Enki, the god of water. Fish frequently appear as filling motifs in cylinder seals from the Old Babylonian (<abbr>c.</abbr> 1830 BC – <abbr>c.</abbr> 1531 BC) and Neo-Assyrian (911–609 BC) periods. Starting during the Kassite Period (<abbr>c.</abbr> 1600 BC – <abbr>c.</abbr> 1155 BC) and lasting until the early Persian Period (550–30 BC), healers and exorcists dressed in ritual garb resembling the bodies of fish. During the Seleucid Period (312–63 BC), the legendary Babylonian culture hero Oannes was said to have dressed in the skin of a fish. Fish were sacred to the Syrian goddess Atargatis and, during her festivals, only her priests were permitted to eat them. In the Book of Jonah, the central figure, a prophet named Jonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on. Early Christians used the ''ichthys'', a symbol of a fish, to represent Jesus. Among the deities said to take the form of a fish are Ikatere of the Polynesians, the shark-god Kāmohoaliʻi of Hawaiʻi, and Matsya of the Hindus. The constellation Pisces ("The Fishes") is associated with a legend from Ancient Rome that Venus and her son Cupid were rescued by two fishes. Fish feature prominently in art, in films such as ''Finding Nemo'' and books such as ''The Old Man and the Sea''. Large fish, particularly sharks, have frequently been the subject of horror movies and thrillers, notably the novel ''Jaws'', made into a film which in turn has been parodied and imitated many times. Piranhas are shown in a similar light to sharks in films such as ''Piranha''. == Referenzi == [[Kategorija:Klassifikazzjoni xjentifika]] [[Kategorija:Annimali]] hykseztr2lpcllat50c68yu74uperz9