Thaum peb tham txog tetrapods, peb yuav tsum paub tias lawv yog ib qho ntawm feem ntau evolutionarily vam meej thiab ntau haiv neeg ntawm vertebrates nyob ntiaj teb. Lawv muaj nyob rau hauv txhua yam ntawm cov chaw nyob, vim hais tias ua tsaug rau qhov tseeb hais tias lawv extremities tau hloov zuj zuj nyob rau hauv ntau txoj kev, lawv tau yoog mus rau lub neej nyob rau hauv lub dej, terrestrial thiab txawm huab cua puag ncig Nws cov yam ntxwv tseem ceeb tshaj plaws yog pom nyob rau hauv keeb kwm ntawm nws cov ceg, tab sis peb puas paub lub ntsiab lus ntawm lo lus tetrapod? Thiab cov vertebrates no tuaj qhov twg los?
Peb yuav qhia koj txog keeb kwm thiab kev hloov pauv ntawm cov tsiaj no, lawv cov yam ntxwv tseem ceeb tshaj plaws thiab peb yuav qhia koj cov piv txwv ntawm txhua tus ntawm lawv. Yog koj xav paub tag nrho cov no ntawm tetrapods, mus nyeem tsab xov xwm no uas peb nthuav qhia rau koj ntawm peb qhov chaw.
tetrapods yog dab tsi?
Cov yam ntxwv tshwj xeeb tshaj plaws ntawm pawg tsiaj no yog muaj plaub ceg tawv (li no nws lub npe, tetra=plaub thiab podos=ko taw). Nws yog ib pawg monophyletic pawg, uas yog hais tias tag nrho nws cov neeg sawv cev sib koom ib tug poj koob yawm txwv, nrog rau lub xub ntiag ntawm hais extremities, uas yog ib tug " evolutionary novelty " (uas yog, ib tug synapomorphy) muaj nyob rau hauv tag nrho cov tswv cuab ntawm pawg no.
No suav nrog amphibians thiab amniotes (cov tsiaj reptiles, noog thiab mammals) thiab, nyob rau hauv lem, yog yus muaj los ntawm pentadactyl libs (nrog 5 ntiv tes) tsim los ntawm ib tug series ntawm articulated segments uas tso cai rau lub txav ntawm ceg thiab txav ntawm lub cev, thiab uas evolved los ntawm fleshy fins ntawm cov ntses ua ntej. lawv (Sarcopterygians). Ntawm tus qauv limb no, ntau yam kev hloov pauv rau lub davhlau, ua luam dej, lossis khiav tau tshwm sim.
Keeb kwm thiab evolution of tetrapods
Kev kov yeej ntawm lub ntiaj teb yog ib qho kev hloov pauv ntev heev thiab tseem ceeb uas cuam tshuam nrog kev hloov kho morphological thiab physiological hauv yuav luag txhua lub cev, uas tau hloov pauv hauv cov ntsiab lus ntawm Devonian ecosystems (kwv yees li 408-360 lab xyoo dhau los), thaum lub sijhawm nws nyob Tiktaalik, twb suav hais tias yog thaj av vertebrate.
Kev hloov ntawm dej mus rau hauv av yog yuav luag ib qho piv txwv ntawm "adaptive radiation" Nyob rau hauv cov txheej txheem no, cov tsiaj uas tau txais tej yam ntxwv (xws li cov ceg tawv thaum ub rau kev taug kev lossis kev muaj peev xwm ua pa tau pa) colonize cov chaw tshiab uas muaj txiaj ntsig zoo rau kev ciaj sia (nrog cov khoom noj tshiab, tsis tshua muaj kev phom sij los ntawm cov tsiaj txhu, kev sib tw nrog lwm hom, thiab lwm yam).). Cov kev hloov kho tau hais txog qhov qhov sib txawv ntawm cov dej hauv ib puag ncig thiab thaj chaw hauv av:
NROG LUB NEJ LOS NTAWM DEJ
NIAM denser tshaj huab cua, thiab lub ntiajteb txawj nqus nyob rau hauv lub terrestrial ib puag ncig. Yog li ntawd, lawv cov pob txha pob txha yog tsim nyob rau hauv ib tugsib txawv tshaj li cov ntses, txij li thaum nyob rau hauv tetrapods nws yuav pom tau hais tias lub vertebrae yog interconnected los ntawm txoj kev ntawm vertebral extensions (zygapophysis) uas tso cai rau tus txha nraub qaum kom khoov thiab tib lub sijhawm ua tus choj ncua kev txhawb nqa lub cev hnyav hauv qab nws.
NOJ NTXHAIS, MUAJ IB YAM RAU SPININE RAU LWM YAM RAU HAUV
Los Ntawm Cov Pob txha taub hau mus rau Caudal cheeb tsam:
- Cervical region: uas ua rau kom lub taub hau txav mus.
- Nkauj tawm tshiab: nrog tav.
- Sacral region: uas cuam tshuam rau lub plab mog thiab hloov lub zog rau locomotion mus rau lub pob txha ntawm ob txhais ceg.
- Caudadal or Tail region: with vertebrae simpler than the trunk.
Nyob rau hauv no tsab xov xwm nyob rau hauv peb lub site peb kuj piav qhia txog keeb kwm thiab evolution ntawm bipedal tsiaj - Piv txwv thiab yam ntxwv.
Tej yam ntxwv ntawm tetrapods
Cov yam ntxwv tseem ceeb ntawm tetrapods yog raws li hauv qab no:
- Ribs: lawv muaj tav uas pab tiv thaiv kab mob hauv nruab nrog cev thiab nyob rau hauv primitive tetrapods lawv txuas mus rau tag nrho vertebral kab. Niaj hnub nimno amphibians, piv txwv li, xyaum poob lawv cov tav thiab hauv cov tsiaj nyeg lawv tsuas yog nyob rau sab xub ntiag ntawm lub cev.
- Lungs: nyob rau hauv lem, lub ntsws (uas twb muaj ua ntej cov tsos ntawm tetrapods thiab uas peb koom nrog lub neej nyob rau hauv av) hloov zuj zuj. rau hauv cov neeg hauv dej xws li amphibians, qhov twg lub ntsws yog cov hnab yooj yim. Txawm li cas los xij, nyob rau hauv cov tsiaj reptiles, noog thiab tsiaj txhu lawv tau muab faib ua ntau yam.
- Cells nrog keratin: ntawm qhov tod tes, ib qho ntawm cov yam ntxwv tseem ceeb ntawm pawg no yog txoj hauv kev uas lawv tiv thaiv lub cev qhuav dej., nrog nplai, plaub hau thiab plaub tsim los ntawm cov tuag thiab keratinized hlwb, uas yog, impregnated nrog ib tug fibrous protein, keratin.
- Reproduction: Lwm qhov teeb meem uas tetrapods ntsib thaum tsiv mus rau thaj av yog qhov ua rau lawv yug me nyuam ywj pheej ntawm cov dej ib puag ncig, qhov no tau ua tiav. los ntawm lub qe amniote nyob rau hauv cov ntaub ntawv ntawm cov tsiaj reptiles, noog thiab mammals. Lub qe no muaj ntau txheej embryonic: amnion, chorion, allantois thiab yolk sac.
- Larvae: Rau lawv ib feem, amphibians nthuav tawm ntau hom kev yug me nyuam nrog rau theem larval (piv txwv li, tadpoles hauv qav) nrog rau sab nraud. gills, thiab ib feem ntawm lawv lub voj voog kev loj hlob tshwm sim nyob rau hauv dej, tsis zoo li lwm yam amphibians xws li ib co salamanders.
- Salivary qog thiab lwm yam: ntawm lwm yam yam ntxwv ntawm tetrapods, peb muaj peev xwm hu rau txoj kev loj hlob ntawm salivary caj pas rau lubricate zaub mov thiab zus tau tej cov digestive enzymes., tus nplaig loj, cov leeg nqaij uas ua haujlwm los ntes cov zaub mov, xws li qee cov tsiaj reptiles, kev tiv thaiv thiab lubrication ntawm lub qhov muag los ntawm daim tawv muag thiab cov qog lacrimal, txais lub suab thiab nws kis mus rau pob ntseg sab hauv.
Piv txwv tetrapods
Ua ib pab pawg megadiverse, peb yuav sau cov piv txwv uas xav paub thiab zoo tshaj plaws ntawm txhua kab uas peb tuaj yeem pom hnub no:
Amphibian Tetrapods
suav nrog anurans (qav), urodelos (salamanders thiab newts) thiab gymnophynas lossis caecilians. Qee qhov piv txwv yog:
- Golden Poison Qav (Phyllobates terribilis): so peculiar for its striking color.
- Fire salamander (Salamandra salamandra): with its brilliant design.
- Cecilia (amphibians uas tau poob lawv ob txhais ceg, uas yog, lawv legless): reminiscent ntawm earthworms, nrog rau cov neeg sawv cev ntawm loj, xws li raws li Thompson tus caecilian (Caecilia thompsoni), uas tuaj yeem ncav cuag 1.5 meters ntev.
Kom nkag siab zoo dua cov tetrapods tshwj xeeb no, koj kuj tuaj yeem txaus siab rau lwm tsab xov xwm no ntawm Qhov twg thiab ua li cas amphibians ua pa?
Sauropsid tetrapods
Suav nrog cov tsiaj reptiles, vaub kib, thiab noog. Qee qhov piv txwv yog:
- Brazilian coral (Micrurus brasiliensis): nrog nws cov tshuaj muaj zog heev.
- Matamata vaub kib (Chelus fimbriatus): xav paub vim nws qhov kev ua zoo nkauj heev.
- Cov noog ntawm lub Vaj Kaj Siab: As rare and intriguingly patterned as Wilson's Bird of Paradise, featuring an incredible color scheme.
Synapsid tetrapods
Hnub no cov tsiaj txhu xws li:
- Platypus (Ornithorhynchus anatinus): tus neeg sawv cev xav paub ntau tshaj plaws.
- Flying fox bat (Acerodon jubatus): ib qho ntawm cov tsiaj ya zoo tshaj plaws.
- Star-nosed mole (Condylura cristata): nrog rau cov cwj pwm hauv av xws li lub hnub qub-nosed mole.
