{"id":90707,"date":"2018-02-13T03:50:00","date_gmt":"2018-02-13T03:50:00","guid":{"rendered":""},"modified":"2023-01-06T20:43:04","modified_gmt":"2023-01-06T20:43:04","slug":"pestii","status":"publish","type":"post","link":"https:\/\/cvnextjob.com\/index.php\/2018\/02\/13\/pestii\/","title":{"rendered":"Pe\u015ftii"},"content":{"rendered":"
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Pe\u015ftii reprezint\u0103 clasa (conform ultimelor clasific\u0103ri-supraclasa)cea mai numeroas\u0103 de animale vertebrate acvatice.Tr\u0103esc \u015fi se reproduc \u00een ap\u0103.Au corpul acoperit de regul\u0103 cu solzi,se deplaseaz\u0103 cu ajutorul \u00eenot\u0103toarelor \u015fi a cozii,respir\u0103 prin branhii(pe\u015ftii dipnoi au \u015fi pl\u0103m\u00eeni)Dup\u0103 structura sceletului se \u00eempart \u00een pe\u015fti cartilagino\u015fi \u015fi oso\u015fi.
Pe\u015ftii cartilagino\u015fi (au scheletul cartilaginos) au ap\u0103rut cu peste 400mln.de ani \u00een urm\u0103 . Majoritatea depun ou\u0103(acoperite cu o coaj\u0103 chitenoas\u0103 rezistent\u0103),care con\u0163in o cantetate mare de galbenu\u015f.Se cunosc circa 630de specii grupate \u00een subclasele holocefali \u015fi elasmobranhieni. Holocefalii actuali s\u00eent reprezenta\u0163i de circa 30 specii de chimeriforme.Cel mai cunoscut este pe\u015ftele chimere-europian\u0103,\u00eent\u00eelnit \u00een marea baren\u0163(partea de sud-est).Are corpul gola\u015f,p\u00een\u0103 la 1,5m lungime,cu o coad\u0103 filiform\u0103,datorit\u0103 c\u0103reia acest pe\u015fte e numit \u015fi \u015fobolan-de-mare.\u00ce\u015fi depune ou\u0103le \u00een ni\u015fte capsule fusiforme de p\u00een\u0103 la 18cm lungime.Chimera-europian\u0103 este apreciat\u0103 pentru gr\u0103simia din ficat,care se folose\u015fte ca substan\u0163\u0103 medicamentoas\u0103. Elasmobranhienii actuali cuprind pe\u015fti din ordinul rechini(circa 250specii)\u015fi ordinul batoidei(circa 350specii) Pe\u015ftii oso\u015fi (au scheletul osos)cuprind subclasele de pe\u015fti sarcopterigieni \u015fi actinopterigieni. Sarcopterigienii la r\u00eendul lor se \u00eempart \u00een pe\u015fti dipnoi \u015fi pe\u015fti crosopterigieni. Pe\u015ftii dipnoi se cunosc din devonian;majoritatea lor au desp\u0103rut de acum.\u00cen prezent exist\u0103 doar 6 specii reprezentan\u0163i ai genurilor neoceratod,lepidosiren \u015fi protopter.Singura specie din primul gen-neoceratodul se \u00eent\u00eelne\u015fte \u00een Australia de nord-est;4specii de protopter-\u00een Africa;pe\u015ftele lenidosiren \u00een bazinul Amazonului.Protopterii \u015fi lenidosirenii se pescuesc. Neoceratodul este ocrotit de lege. Crosopterigienii se cunosc din devonian \u015fi au disp\u0103rut aproape \u00een \u00eentregime \u00een cretacicul superior.Ei s\u00eent considera\u0163i str\u0103mo\u015fii ai vertebratelor terestre.Unicul reprezentant actual al crosopteri- gienelor este latimeria ,care are corpul p\u00een\u0103 la 180cm lungime,masa de p\u00een\u0103 la 95kg \u015fi o colora\u0163ie albastr\u0103-metalic\u0103.Ea este un animal ovovipar.Tr\u0103e\u015fte \u00een regiunea insulelor Komore.Primul exemplar de latimerie a fost prins \u00een anul 1938 l\u00eeng\u0103 Africa de sud(unde a ajuns \u00eent\u00eepl\u0103tor). Dintre actinopterigieni cei mai r\u0103sp\u00eendi\u0163i \u015fi mai cunoscu\u0163i s\u00eent teleostenii sau pe\u015ftii oso\u015fi propriuzi\u015fi,care num\u0103r\u0103 peste 20000 de specii atuale.Ei au ap\u0103rut circa 200mln.ani \u00een urm\u0103.Unii tr\u0103esc \u00een apele marine(scrumbiile,anciou\u015fii,pe\u015ftii-zbur\u0103tori,scombridele \u015f.a.),iar al\u0163ii populeaz\u0103 apele dulci (salmoniformele,cipriniformele,unele specii de perciforme \u015fi siluriforme).\u015ei printre pe\u015ftii oso\u015fi axist\u0103 pe\u015fti electrici,de exemplu;anghila-electric\u0103,somnul-electric \u015f.a.Ei de-a semenea au organe electrice care produc desc\u0103rc\u0103ri electrice la tensiuni de 350-650 vol\u0163i.Cu ajutorul lor pe\u015ftii \u00ee\u015fi ame\u0163esc victima sau speie du\u015fmanii. Pe\u015ftii oso\u015fi au corpul de forme variate:de fus(scrumbia,somnul),de s\u0103geat\u0103(z\u0103rganul,\u015ftiuca), de \u015farpe(anghila),de ac(acul-de-mare),turtit(pl\u0103tica,caracuda),de disc(cambula),de sfer\u0103(pe\u015ftele-lu-n\u0103)\u015f.a. Pe\u015ftii difer\u0103 mult \u015fi dup\u0103 culoare care totdeauna are un rol protector.Speciile care populeaz\u0103 p\u0103turile superioare ale apei au un luciu argintiu(ocheana,sabi\u0163a,scrumbia),cele care tr\u0103esc la fundul apelor nu au acest luciu,pe\u015ftii abisali(de mare ad\u00eencime)au o culoare ro\u015fietic\u0103,cafenie \u015fi neagr\u0103-violet\u0103,iar cambula poate sa-\u015fi schimbe culoarea dup\u0103 culoarea nisipului sau a scoicilor. Unii pe\u015fti(cleanul,p\u0103str\u0103vul,somnul)s\u00eent capabili s\u0103 axecute mi\u015fc\u0103ri foarte iu\u0163i \u015fi pot \u00eenvinge cu u\u015furin\u0163\u0103 curen\u0163ii puternici de ap\u0103,fapt care le permite s\u0103 tr\u0103iasc\u0103 \u00een r\u00eeurile de munte,s\u0103 urce pe cursul lor superioer pentru a depune icre,str\u0103b\u0103t\u00eend \u00een acest scop praguri \u015fi mici cascade de ap\u0103.Cel mai mare rapid pe\u015fte este considerat tonul,care dezvolt\u0103 o vitez\u0103 de p\u00een\u0103 la 90km pe or\u0103. E foarte interesant pe\u015ftele numit guvid-s\u0103ritor \u00eent\u00eelnit \u00een lagunele unor r\u00eeuri din Australia,Asia,\u015fi Africa unde cresc adev\u0103rate desi\u015furi de mangrove.Datorit\u0103 \u00eenot\u0103toarelor pectorale lungi \u015fi puternice el se ca\u0163\u0103r\u0103 cu u\u015furin\u0163\u0103 pe arborii de mangrove \u015fi v\u00eeneaz\u0103 insecte.\u00centruc\u00eet respir\u0103 \u015fi aer atmosferic,acest pe\u015fti\u015for de 15cm se poate afla \u00een afara mediului acvatic un timp \u00eendelungat. Majoritatea pe\u015ftelor migreaz\u0103 \u00een perioada de \u00eenmul\u0163ire.Pe\u015ftii de r\u00eeu urc\u0103 spre cursul superior al apei pentru a-\u015fi depune icrele pe plante acvatice,pe pietre.Scrumbiile \u00ee\u015fi depun icrele \u00een ad\u00eencul apelor.Unii pe\u015fti marini(sturionii,clupeidele,salmonidele) \u00ee\u015fi p\u0103r\u0103sesc mediul obi\u015fnuit de via\u0163\u0103 \u015fi \u00ee\u015fi
depun icrele \u00een r\u00eeuri,\u00een timp ce anghila,din contra,pentru a-\u015fi depune icrele trece din r\u00eeuri \u00een m\u0103ri \u015fi oceane. Pe\u015ftii sunt foarte varia\u0163i at\u00eet dup\u0103 dimensiuni,c\u00eet \u015fi dup\u0103 durata vie\u0163ii,\u00eentre care parc\u0103 sxist\u0103 o anumit\u0103 corela\u0163ie:se cunosc guvizi de 7,5-11mm care tr\u0103esc cel mult un an,pe c\u00eend morunul,care atinge uneori 800-1000kg,tr\u0103e\u015fte aproape 100ani. Cele mai mici vibra\u0163ii ale apii pe\u015ftii le percep cu ajutorul unui organ numit linie lateral\u0103.Un alt organ interesant este cel hidrostatic de echilibru,precum \u015fi de producere a sunetelor,denumit vezic\u0103 \u00eenot\u0103toare.Pe\u015ftii lipsi\u0163i de acest organ(fusarul,zgl\u0103vocul,scrumbia-albastr\u0103),care tr\u0103esc pe fundul apelor urc\u0103 spre suprafa\u0163a apei \u015fi se scufund\u0103 cu u\u015furin\u0163\u0103. Pe\u015ftii ajung la maturitate sexual\u0103 la diferite perioade:Jinjirica,guvidul-la c\u00eeteva luni,carpul, pl\u0103tica,\u015f\u0103l\u0103ul-la 3-4ani,morunul,nisetrul,abia la 14-18ani.Fecunditatea pe\u015ftelor variaz\u0103 de la c\u00eeteva zeci de icre(la ghidrin,acul-de-mare)la 1-9mln.(la cambul\u00ee \u015fi morua)\u015fi chiar p\u00een\u0103 la 300mln.(la pe\u015ftele lun\u0103). Majoritatea speciilor de pe\u015fte s\u00eent adaptate la un anumit fel de hran\u0103.Speciile r\u0103pitoare se hr\u0103nesc \u00een special,cu pe\u015fti mai mici(\u015fal\u0103ul,somnul,\u015ftiuca \u015f.a.).Pe\u015ftii care se hr\u0103nesc cu nevertebrate de fund(amurul-negru,pl\u0103tica,linul) au din\u0163ii maxilari sau faringieni puternic dezvolta\u0163i.Multe specii de exempu(scrumbiele,ciprinidele)se hr\u0103nesc,\u00een special cu animale planctonice,altele(bun\u0103uar\u0103,ambul-alb,hipoftalmictisul-alb,ro\u015fioara,scobarul)-numai cu vegeta\u0163ie acvatic\u0103.<\/div>\n","protected":false},"excerpt":{"rendered":"

Pe\u015ftii reprezint\u0103 clasa (conform ultimelor clasific\u0103ri-supraclasa)cea mai numeroas\u0103 de animale vertebrate acvatice.Tr\u0103esc \u015fi se reproduc \u00een ap\u0103.Au corpul acoperit de regul\u0103 cu solzi,se deplaseaz\u0103 cu ajutorul \u00eenot\u0103toarelor \u015fi a cozii,respir\u0103 prin branhii(pe\u015ftii dipnoi au \u015fi pl\u0103m\u00eeni)Dup\u0103 structura sceletului se \u00eempart \u00een pe\u015fti cartilagino\u015fi \u015fi oso\u015fi.Pe\u015ftii cartilagino\u015fi (au scheletul cartilaginos) au ap\u0103rut cu peste 400mln.de ani […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts\/90707"}],"collection":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/comments?post=90707"}],"version-history":[{"count":0,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/posts\/90707\/revisions"}],"wp:attachment":[{"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/media?parent=90707"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/categories?post=90707"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cvnextjob.com\/index.php\/wp-json\/wp\/v2\/tags?post=90707"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}