Nyob rau hauv txhua qhov ecosystem peb pom cov tsiaj uas muaj lub luag haujlwm tseem ceeb hauv nws qhov kev hloov pauv, txij li los ntawm qhov pom ntawm trophic lawv tsis muaj cov tsiaj nyeg thiab lawv lub taub hau ntawm lub pyramid. Yog li ntawd, peb muaj cov sharks, uas yog undoubtedly survivors rau muaj kev tswj kom dim ntau yam loj extinctions uas tau tshwm sim nyob rau hauv lub ntiaj teb no.
Ntawm lub evolutionary keeb kwm ntawm cov ntses, ntau hom tau ploj mus, hos ib txhia tau tswj mus rau txoj kev ntawm lub neej, txawm muab txoj kev rau lwm tus los yog nyob rau hauv lub sij hawm, cov uas niaj hnub no peb hu ua fossils nyob.. Ntawm no yog ib tsab xov xwm los ntawm peb qhov chaw hais txog prehistoric sharks, extinct and living exampleNyob nyeem ntawv thiab kawm paub ntxiv txog cov tsiaj ntxim nyiam no.
Characteristics of prehistoric sharks
Sharks (Selachimorpha) yog ib pab neeg qub heev ntawm cov ntses cartilaginous, uas tau hloov zuj zus nyob ib ncig ntawm 400 lab xyoo dhau los. Qhov no qhia txog lawv lub xub ntiag txawm tias ua ntej cov dinosaurs lawv tus kheej. Shark fossils raug txwv ntau, dua li lwm pab pawg, vim:
- Lub sij hawm dhau mus.
- Cov xwm txheej ntawm ib puag ncig marine uas feem ntau ua rau nws nyuaj rau khaws cov seem.
- Lub cev pob txha mos.
Txawm li cas los xij,cov kws tshawb fawb tau tswj hwm qee yam yam ntxwv, tus pob txha caj qaum, pob txha caj qaum lossis pob txha pob txha caj qaum khaws cia thiab lawv peculiar nplai. Cov ntaub ntawv qub tshaj plaws ntawm shark scale yog nyob ib ncig ntawm 420 lab xyoo thiab sib haum mus rau tam sim no Siberia; Raws li cov hniav, lawv tuaj txog li 400 lab xyoo dhau los nyob rau niaj hnub Europe. Tseem muaj cov pob txha taub hau uas muaj hnub nyoog 380 lab xyoo, nyob hauv New South Wales hauv Australia.
Tom ntej no, cia peb kawm txog qee qhov nta:
- Cov hniav tau mineralogically ruaj khov, uas tso cai rau nws cov txij nkawm thoob plaws hauv keeb kwm geological ntawm dej hiav txwv. Tsis tas li, zoo li sharks niaj hnub no, cov qauv kho hniav no tau hloov tau.
- Ib txhia hom hniav ntawm cov tsiaj txhu prehistoric no tau piav raws li me me, ob-cusped thiab tsis muaj qhov ntse lossis serrated zoo li pom hnub no.
- , uas ua rau nws muaj peev xwm txheeb xyuas tau tias lawv muaj tseeb sib raug rau sharks.
- Kwv yees tias cov tsiaj no yog tsawg agile.
- Prehistoric sharks muaj ntau haiv neeg ntau dua li niaj hnub no, kwv yees tias muaj twice as many species. Txawm li cas los xij, cov no tau dhau los ua cov xwm txheej loj kawg nkaus.
- Ntau cov ntses thaum ub muaj paj snouts, tsis zoo li cov tam sim no uas muaj elongated snouts.
- Brains tau tus cwj pwm los ntawm kev ua me dua li niaj hnub no.
- As for the fins, they have tseem yoog.
- Lawv lub cev kuj tau tsim los ntawm pob txha mos pob txha.
- Lawv muaj, zoo li tam sim no, ntau yam gill slits. Tsis txhob ua siab deb sab laj nrog cov lus no nrog qee Cov Tsiaj Ua Ntsig Ua pa ntawm gills.
Raws li peb tau hais ua ntej lawm, cov ntses no tau dhau los ntawm ntau lub sijhawm ntawm kev ploj tuag, uas yog vim li cas ntau hom sharks prehistoric tau ploj mus. Cia peb kawm paub qee yam:
Antarctilamna
Cov genus no tau piav qhia los ntawm pob txha taub hau, uas yog suav tias yog qhov qub tshaj plaws nyob rau hauv cov dej tshiab. Cov kev xav ntawm fin spines thiab cov hniav kuj pom. Cov kev tshawb pom tau nyob hauv Australia, Saudi Arabia thiab lwm thaj chaw.
NOJ TOM ZOO KAWG LI CAS
ZAUB MOV TAWM lub fin dorsal thiab ob-pointed hniav. Cov yam ntxwv zoo ib yam li prehistoric sharks ntawm pawg xenacanthus.
Xenacanthiformes
Lub sij hawm xenacanthus txhais tau tias qaum qaum Ntau yam genera ntawm heev primitive extinct sharks tau nyob rau hauv pawg no. Lawv yuav luag tshwj xeeb rau dej ntshiab ib puag ncig, nrog rau lub xub ntiag ntawm ib tug ntev backward-directed fin nyob rau sab nraum qab ntawm lub pob txha taub hau, ob-taw cov hniav, thiab cov duab. ntawm lub cev yog similar to eels
Elegestolepis
Corresponds to a genus of extinct prehistoric shark, suav hais tias yog ib qho ntawm cov laus tshaj plaws. Nws nyob ntau tshaj 400 lab xyoo dhau los, nyob rau lub sijhawm Silurian thiab Devonian, thiab cov seem ntawm cov nplai tau pom nyob rau niaj hnub Russia xyoo 1973. ob peb lub cev ntawm nws lub cev, nws tsis paub meej tias lub cev ntawm tus shark no zoo li cas, txawm tias cov kws tshaj lij muaj lub tswv yim me ntsis.
Aquilolamna milarcae
Nov yog ib hom ntawm cov ntses uas ploj lawm nyob rau hauv no genus, pom nyob rau hauv Mexico. Cov pob txha zoo khaws cia tau qhia tias nws yog ib tus neeg tshwj xeeb, nrog lub cev torpedo-puab lub cev, tus Tsov tus tw zoo ib yam li cov sharks niaj hnub no, tab sis lubatypically long pectoral fins uas zoo li hom tis.
Orthacanthus
Cov genus no suav nrog ntau hom ntses ntses uas ploj lawm, nrog cov cwj pwm dej tshiab. Nws tau raug qhia tias were carnivorous, with possible sexual dimorphism vim muaj qhov sib txawv hauv cov hniav loj. Nrog qhov ntev ntawm txog li 3 meters, lawv tau nyob rau niaj hnub Europe thiab North America.
Tsis txhob yig tau sab laj nrog lwm tus tshaj tawm txog kev sib deev Dimorphism: txhais, xav paub thiab piv txwv, ntawm no.
Sharks, tau muaj los ntev, peb tuaj yeem hais tias feem ntau lawv yog ib pab pawg qub heev. Txawm li cas los xij, niaj hnub no tseem muaj hom nrog cov yam ntxwv uas ua rau lawv suav tias yog as live prehistoric sharks, cia wb ntsib lawv ib pliag:
Hexanchiformes
Nws yog ib tug ntawm cov laus tshaj plaws nyob rau hauv lub neej tam sim no thiab lawv muaj lub npe hu ua Cowsharks, leej twg fuse ancient thiab niaj hnub zoo. Lawv muab faib ua 3 tsev neeg thiab 5 hom. Nws cov yam ntxwv tseem ceeb yog:
- Lawv nthuav tawm 6 los yog 7 khub gill slits.
- Lawv muaj lub qhov quav thiab ib lub dorsal fin.
- Lawv yog ovoviviparous thiab muaj tshwj xeeb tshaj yog marine cwj pwm, dej kub thiab dej hiav txwv kub ntawm Atlantic, Indian thiab Pacific dej hiav txwv. Peb tso koj cov ntawv tshaj tawm no rau ntawm peb qhov chaw nrog Ovoviviparous Tsiaj: piv txwv thiab xav paub ntxiv txog kev kawm.
- Lawv nyob hauv qhov tob heev, yuav luag tsis muaj neeg nkag.
- Lawv muaj , cov hom loj tshaj plaws yog Hexanchus griseus nrog txog 4.8 meters ntev, thiab qhov tsawg tshaj plaws Heptranchias perlo uas ncav cuag 1.4 meters.
Chlamydoselachiformes
Known as ya sharks, lawv suav hais tias yog fossils nyob. Cov pab pawg muaj ib lub genus thiab ob hom, Chlamydoselachus anguineus thiab Chlamydoselachus africana. Ntawm cov yam ntxwv tseem ceeb peb pom:
- Lub cev yog eel-like.
- Lawv muaj ob lub qhov quav thiab dorsal fin.
- Lawv yog ovoviviparous and have exclusively marine habits, in dej tob ntawm Atlantic, Indian thiab Pacific dej hiav txwv.
- Qhov loj tshaj plaws yog hom C. anguineus, uas nce mus txog li ntawm 2 meters ntev.
ZAUB Yog Teb Dhuav yog Blunt nyob rau hauv cov duab thiab lub NIAM TUAG
Dab tsi yog qhov loj tshaj plaws prehistoric shark?
Sharks undoubtedly khaws ib tug series ntawm fascinating thiab xav paub cov ntaub ntawv, thiab ib yam ntawm cov no muaj feem xyuam rau qhov loj. Yog tias koj tau xav paub yog tias Giant prehistoric sharks existed, lo lus teb yog lawm. Fossil pov thawj tau tsim kom muaj ib tug prehistoric shark ntawm enormous proportions uas yog feem ntau hu ua megalodon (Carcharocles megalodon).
NOJ MEGA PREDATOR MUAJ IB TUG NEEG TSIS TAU CAS THAUM AG NTXHU- thiab ntev li sai tau txog 2 xyoos dhau los, 5 txog 3 lab xyoo dhau los
Kev tshawb pom ntawm cov hniav, qhov seem ntawm lub puab tsaig thiab pob txha caj qaum hauv cov tebchaws xws li Tebchaws Meskas, Panama, Cuba, Canary Islands, Africa, India, Australia thiab Nyiv, thiab lwm yam, paub meej tias tias, yog muaj, nws kuj yog ib hom uas muaj ntau yam faib.
Vim li cas lub megalodon thiaj li ploj mus? Tshawb nrhiav cov lus teb rau lo lus nug no hauv cov ntawv nram qab no uas peb qhia.
