Shin cartilaginous kifi kiki reshe na juyin halitta?

Cartilaginous kifi suke, ba shakka, a baya fiye da takwarorinsu kashi. Amma ko wannan al'amari ya sa ya yiwu don tabbatar da cewa wadannan tsoho halittun - ajizai yara yanayi, play idan aka kwatanta da su karin ci-gaba "abokan aiki"? Ka yi la'akari da asali bambance-bambance. Babban alama, wanda shi ne dalilin da ya sa aji samu da sunan, shi ne wani cartilaginous kwarangwal. Har ila yau, ba su da wani iyo mafitsara (ko da yake shi ba ya wanzu, da kuma a wasu fitar kasusuwan jikinsu kifi, misali, zurfin). Tun lokacin da takamaiman nauyi na dabba shi ne mafi tsananin fiye da ruwa, shi ne ba don zuwa kasa, ya kamata ya kasance ko da yaushe a kan tafi. Sanya shi a cikin wani akwatin kifaye, sun kawai shaƙa ko da idan ruwa ne bayyananne: domin saturate da jini tare da oxygen, shi wajibi ne don tsotso mai yawa da ruwa, ta hanyar da gills, wanda aka samu da ci gaba da motsi.

Bugu da ari, cartilaginous kifi da gill maida hankali ne akan yadda kashi. Ramummuka overt airway. Suna kan gefen kai. A holocephali (chimeras) daya kawai gill tsaguwa, sharks da kuma 'yan stingrays. Bugu da kari, bayan da dabba ta idanu ne wani Gill - Spiracle. Sharks ne rudiment, kuma gangara ake rayayye ta yin amfani da Spiracle (da suka yi shi matabbaci a saman da kai) a lokacin da jiran su ganima binne shi a cikin yashi. Lokacin da iyo, wadannan halittu hadiye ruwa da bakinsa, da kuma saki a gare shi ta hanyar da rami.

Abin da kuma ya bambanta da aji "cartilaginous kifi"? Sifofinsu su shi ne cewa su duk da placoid ma'auni. Wannan musamman farantin, shugaba hakori da daya ko biyu gefuna. Daga cikin wadannan haskoki kunshi spines, filafilin kifi spines wasu jinsunan sharks, "sawa-hakora" a cikin saw-kifi da, ta hanyar, gaskiya, kasancewa a cikin muƙamuƙi hakora na cartilaginous aji. Amma a nan akwai wani kwatankwacinsa da chimeras dvoyakodyshaschmi - taban da ake jikinsu garwaya a cikin biyu faranti, da nika shuka abinci. Har ila yau, lura da cewa chimera yana da halaye na da yawan jama'a na fitar kasusuwan jikinsu zurfin - tsirkiya su riƙe cikin rayuwarsu. Sunan kanta (as zamanin d Helenawa Kwafa yanci halittu, wanda ya hada siffofin da halittu daban-daban - a centaur, sphinx) characterizes wadannan halittu masu ban mamaki: su ne ba kawai garwaya da sifofin da kashi da guringuntsi, amma kuma su wutsiya yayi kama da bera ta sa suna kuma kira "teku berayen. "

Class "cartilaginous kifi" ne zuwa kashi biyu subclasses: holocephali (Chimera) da kuma elasmobranch. Na biyu ne zuwa kashi kungiyoyin: sharks da kuma haskoki. Wakilainsu da yawa kamance tsakanin su. Za mu iya cewa da tudun lodi - shi ne "flattened sharks", ko da yake wannan bayani ne ma simplistic. Gill slits su ne a ciki, yayin da toothed hischnits- bangarorin. Akwai game da 350 jinsunan haskoki: daga cikinsu akwai pilorylye (ba za a rikita batun tare da sawshark!), Stingray kuma high. Idan stingray dũka da ganima da guba, allura a cikin jiki ta hanyar da karu, lantarki kashe ta high-ƙarfin lantarki sallama. Mafi Girma view na Duniya - Manta - tare da su giant size (sikelin "fuka-fuki" na har zuwa 8 mita) Ciyarwar a plankton.

Amma mafi mashahuri a cikin mutum al'ada ne cartilaginous kifaye kamar kifayen teku. Wanda akwai 250 jinsunan, kuma suna rarraba a duk teku, daga ekweita da iyakacin duniya latitudes. Da girmansu Range daga 15 santimita (cat) har zuwa 20 mita (Whale). Ba wai kawai da yawan zafin jiki na ruwa ba tsorata da shark, amma ta gwargwado: suka hadu a estuaries da nisa da tushe, inda Suna cikin tafiya a cikin bege don kai farmaki da migrating shanu. A adabi da kuma film, da suka sanã'anta take ba sosai flattering ko da yaushe jin yunwa ciki ba tare da kwakwalwarmu, m kuma insatiable. A ra'ayi na "fetal siblicide" zo a cikin yin amfani da bayan mutane gano cewa, live-hali kifi tãyuna ci juna a cikin mahaifa.

Shin cartilaginous kifi dozhivshim ga lokaci aji na prehistoric dabbobi, wani irin matattu karshen a ci gaba, kamar yadda wasu ichthyologists? Haka kuma, ba su da aka gudanar a kan kwarangwal samuwar, amma shi ba ya nufin cewa ƙasusuwansu ne taushi. Ƙarƙashin rinjayar mineralization na kwarangwal a wata hanya ba, baya zuwa taurin da sauran jinsunan. A cewar wasu halaye (babu gill slits kuma da iyo mafitsara) suka nuna wani juyin "slack" a kwatanta da kostevymi, amma suna da ciki hadi, da kuma da dama da suka jinsunan - viviparous ko ovoviviparous. Kuma wasu ma sharks haifar da "Yara Place" kamar yadda placental dabbobi.