ʻIchthyostega

Ichthyostega - kahi ʻano o nā holoholona make, pili pono i nā tetrapods (ʻehā vertebrates terrestrial terrestrial terrestrial). Ua ʻike ʻia ia ma ke ʻano he pōhaku fossilized ma ka hikina o Greenland o ka hopena o ka manawa ʻo Devonian ma kahi o 370 miliona mau makahiki i hala. ʻOiai ʻo Ichthyosteg i kapa ʻia he "tetrapod" ma muli o kona mau lālā a me nā manamana lima, he ʻano basal "primitive" ʻoi aku ka nui ma mua o nā tetrapods kalaunu maoli, a hiki ke kapa ʻia me ka pololei he stegocephalic a i ʻole stem tetrapod.

Ke kumu o ka laha a me ka wehewehe

Kiʻi: ʻIchthyostega

ʻO Ichthyostega (mai ka Helene "kaupaku iʻa") kahi ʻano mua mai ka papa o tetrapodomorphs i noho i ka hopena o Devonia. ʻO ia kekahi o nā vertebrates ʻehā ʻehā i loaʻa i nā fossil. He mau māmā a me nā lālā ʻo Ichthyostega nāna i kōkua iā ia e hoʻokele i ka wai pāpaʻu i nā poho. Ma ka hoʻolālā a me nā maʻamau, ʻaʻole ia i manaʻo ʻia he lālā maoli o ka hui, ʻoiai nā amphibians hou (nā lālā o ka hui Lissamphibia) i kū mai i ka wā Triassic.

Video: ʻIchthyostega

ʻOiaʻiʻo hoihoi: ʻEhā mau ʻano i wehewehe mua ʻia a wehewehe ʻia kahi ʻano ʻelua, ʻo Ichthyostegopsis. Akā ua hōʻike hou ʻia kahi noiʻi hou i ke ola ʻana o ʻekolu mau ʻano hilinaʻi e pili ana i nā kaulike o ka iwi poʻo a pili i nā ʻano ʻekolu.

A hiki i ka loaʻa ʻana o nā stegocephals mua a me nā iʻa pili pono i ka hopena o ke kenekulia 20, ʻo Ichthyostega ka mea i loaʻa ma ke ʻano he mōʻalihaku hoʻololi ma waena o nā iʻa a me nā tetrapods, e hui pū ana nā iʻa a me nā tetrapods. Ua hōʻike ʻia kahi noiʻi hou he anatomy ʻokoʻa kāna.

ʻO ka maʻamau, ʻo Ichthyostega ka papa paraphyletic o nā tetrapod kumu kumu mua loa, no laila ʻaʻole ia i hoʻokaʻawale ʻia e nā mea noiʻi o kēia au he kūpuna o nā lā hou. Ua hōʻike ʻia ke kālailai phylogenetic he loulou waena ka ichthyosteg ma waena o nā tetrapods stegocephalic stem primitive. I ka 2012, ua hōʻuluʻulu ʻo Schwartz i kahi lāʻau ulu o nā stegocephals mua.

ʻO ka helehelena a me nā hiʻohiʻona

Kiʻi: He aha ke ʻano o ka ichthyostega

ʻO Ichthyostega ma kahi o hoʻokahi a me ka hapalua mika ka loa a heʻuʻuku dorsal fin ma ka lihi o ka huelo. Loaʻa iā ia ka huelo i ke kākoʻo o ka iwi i kākoʻo ʻia i loko o ka iʻa. ʻO nā hiʻohiʻona ʻē aʻe e mau ana i nā vertebrates wai mua e komo pū me kahi muzzles pōkole, ke kū ʻana o kahi iwi preopercular i ka ʻāpana papalina e lawelawe ana ma ke ʻāpana o nā gills, a me nā unahi liʻiliʻi ma ke kino. ʻO nā ʻano holomua i maʻa mau ʻia i ka tetrapods kahi ʻāpana o nā iwi ikaika e kākoʻo ana i nā lālā momona, ka nele o nā gills a me nā iwi ʻaoʻao ikaika.

Mea hoihoi: ʻO Ichthyostega a me kona mau hoahānau e hōʻike i nā ʻano i ʻoi aku ka maikaʻi ma mua o ka wai Eusthenopteron, a ʻike ʻia kokoke i ka laina evolution e alakaʻi ana i nā tetrapod mua ma ka ʻāina.

ʻO ka hiʻona kaulana loa o ka iwi axial o ka ichthyosteg ka nui i hoʻopili ʻia nā iwi ʻaoʻao. E hoʻopili paha kekahi iwi ʻaoʻao i ʻekolu a ʻehā mau iwi ʻaoʻao hope, e hana ana i kahi "corset" ʻano like barela a puni ke kino. Hōʻike kēia ʻaʻole hiki i ka holoholona ke pelu i ke kino mai ka ʻaoʻao ke hele a ʻauʻau paha. ʻAʻole chordate ka vertebrae, akā ʻoi aku ka nui o nā zygapophyses koʻikoʻi i nā aʻa nerve.

Hiki ke manaʻo ʻia ua neʻe ka holoholona ma mua o ka hopena o ka dorsoventral flexion ma mua o ka hele wāwae maʻamau. Ua hoʻohana ʻia paha nā forelimbs nunui e huki ai i ka holoholona i mua a laila kūlou i ka ʻāpana presacral e hoʻopaʻa i ka hope. ʻO nā lālā hope i loko o kahi femur pōkole, mānoanoa me kahi flange nui a me kahi adductor deep intercondylar fossa.

ʻO ka tibia nui aʻe, ʻaneʻane quadrangular tibia a me nā fibula pōkole i pālahalaha ʻia. ʻO ka waena nui a me ka fibula i komo i ka hapa nui o nā iwi kuʻekuʻe. ʻO kahi hōʻike i mālama pono ʻia, i hōʻiliʻili ʻia i ka makahiki 1987, e hōʻike ana i kahi piha piha o nā manamana ʻehiku, ʻekolu mau liʻiliʻi ma ka lihi alakaʻi a ʻehā piha i ka hope.

Ma hea e noho ai ʻo Ichthyostega?

Kiʻi: ʻIchthyostega i loko o ka wai

Loaʻa nā koena o kahi ichthyosteg ma Greenland. ʻOiai ʻike ʻole ʻia ke ʻano kikoʻī o nā laha, hiki ke manaʻo ʻia he mau kupa nā ichthyostegs o ka hemisphere ʻākau. A noho lākou i ka wai o ʻAkelanika a me ke Kai ʻAkika. Hōʻike ʻia ka wā Devonian e kahi ʻano mahana mehana, a me ka ʻole paha o nā glaciers. ʻAʻole like ka divergence wela mai ka equator a hiki i nā pou i like me kēia lā. Ua maloʻo loa ke anilā, ma ke kaʻe o ka equator, kahi o ka wā maloʻo loa.

Mea hoihoi: ʻO ke kūkulu hou ʻia ʻana o ka mahana o ka moana tropical e ʻae i ka awelika o 25 ° C i ka wā mua o Devonian. Ua hōʻole nui nā pae o carbon dioxide i ka wā o ka Devonian, ʻoiai ke kanu ʻana o nā ululāʻau hou i huki i ke kalapona mai ka lewa i nā sediment. Hōʻike ʻia kēia i ke kau waena o Devonian e ka ʻoluʻolu o nā mahana a hiki i ka 5 ° C. Hoʻohālikelike ʻia ka Late Devonian e ka hoʻonui ʻana o ka mahana i kahi pae i kūlike i ka Early Devonian.

I kēlā manawa, ʻaʻohe piʻi like o nā concentrations CO uka a hoʻonui ʻia ke anilā ʻĀinapuni (e like me ka mea i hōʻike ʻia e nā mahana kiʻekiʻe). Eia hou, he nui nā hōʻike, e like me ka hoʻohele ʻana o nā mea kanu, kuhikuhi i kahi hoʻomehana Late Devonian. Aia i kēia manawa i hoʻopaʻa ʻia nā fossil i loaʻa. Hiki paha ke mālama ʻia nā ichthyostegs i ka wā Carboniferous e hiki mai ana. Pili paha ko lākou nalowale hou ʻana me ka hoʻemi o ka mahana i ko lākou wahi noho.

I loko o kēia wā, ua hoʻopilikia ke aniau i nā meaola i loko o nā pali, ʻo nā microbes nā meaola kōkō i hana ʻia i nā wā mehana, a ua hoʻokani nui nā pākako a me nā stromatoporoids i nā manawa anuanu. ʻO ka hoʻomehana ʻana i ka hope o Devonian ua kōkua paha i ka nalowale o stromatoporoids.

I kēia manawa ʻike ʻoe i kahi i loaʻa ai ka ichthyosteg. E nānā kāua i ʻai ai.

He aha ka mea a Ichthyostega i ʻai ai?

Kiʻi: ʻIchthyostega

Kūlou maikaʻi ʻole nā ​​manamana o ka ichthyosteg, a nāwaliwali ka ʻōnaehana muscular, akā ʻo ka holoholona, ​​me ka hoʻohui i ka wai kai, ua hiki ke neʻe ma nā wahi pohopoho o ka ʻāina. Inā mākou e noʻonoʻo i ka leʻaleʻa o ka ichthyostega i ka manawa pakeneka, a laila 70-80% o ka manawa i lanakila ai ʻo ia i ka wai, a me ke koena o ka manawa ua hoʻāʻo ʻo ia e haku i ka ʻāina. ʻO nā kumuwaiwai nui o ia wahi nā kamaʻāina o nā kai o ia au, nā iʻa, plankton moana, nā mea kanu kai paha. ʻO ke kai kiʻekiʻe ma ka Devonian kiʻekiʻe kiʻekiʻe.

Ua hoʻomalu ʻia nā fauna moana e:

• bryozoans;
• nā ʻano like ʻole a nui nā brachiopods;
• gederellids pohihihi;
• microconchids;
• crinoids like lily nā holoholona, ​​ʻoiai ke ʻano like me nā pua, ua nui;
• he laha mau ka trilobites.

Hiki paha iā Ichthyostega ke ʻai i kekahi o kēia ʻano. Ma mua, pili nā ʻepekema i ka ichthyostega me ke ʻano o tetrapods ma ka ʻāina. Eia nō naʻe, ua hele aku paha i ka ʻāina no kekahi manawa pōkole loa, a hoʻi hou i ka wai. ʻO wai o ka vertebrates kahiko i lilo i mea ʻike maoli i ka ʻāina i koe e ʻike ʻia.

Na ka wā Devonian, ke holo nei ke ola i ke kaʻina o ka kolone ʻana i ka ʻāina. ʻO nā ululāʻau limu silurian a me nā moena koʻohune i ka hoʻomaka o ka wā i loko o nā mea kanu aʻa kumu i hana i nā lepo kūpale mua a me nā arthropods e like me nā mites, scorpions, trigonotarbids a me millipedes. ʻOiai ua ʻike ʻia nā arthropods ma ka honua ma mua o ka Devonian mua, a ke hōʻike nei ke ola o nā fossil e like me Climactichnites e like paha me ka Cambrian i hōʻike mua ʻia nā arthropod terrestrial.

Ua ʻike ʻia nā fossil insect hiki mua i ka Devonian mua. Hōʻike ʻia nā ʻikepili tetrapod mua loa ma ke ʻano he mau kapuwaʻi fossil i nā lagoon pāpaʻu o ke kahua kalapona kūwaho a me ka papa i ka wā o ka Middle Devonian, ʻoiai ua nīnau ʻia kēia mau kapuaʻi a ua kuhi ka poʻe ʻepekema i nā lawaiʻa iʻa iʻa. ʻO kēia flora a me nā holoholona e ulu wikiwiki nei kahi kumu meaʻai kūpono na Ichthyosteg.

Nā hiʻohiʻona o ke ʻano a me ka nohona

Kiʻi: Extch Ichthyostega

Ua hoʻonohonoho ʻia ka makahiki o ka holoholona ma 370 miliona mau makahiki a ua kau ʻia i ka wā Devonian. ʻO Ichthyostega kekahi o nā tetrapod kahiko loa. Ma muli o kona ʻano, i hoʻopili ʻia me nā ʻano o nā iʻa ʻelua a me nā amphibians, ua lawelawe ʻo Ichthyostega ma ke ʻano he kūlana kiʻekiʻe a me nā hōʻike morphological no ke kumumanaʻo o ka evolution.

ʻOiaʻiʻo hoihoi: ʻO kekahi o nā mea ʻoi loa e pili ana i ka ichthyosteg ʻaʻole ia he webbeded wawae ʻo ia, akā ua hiki iā ia ke hanu i ka ea - ma ka liʻiliʻi no nā manawa pōkole. Eia nō naʻe, me kēia hiki kamahaʻo, ʻaʻole paha ʻo ia i hoʻolōʻihi i ka manawa ma ka ʻāina. ʻO kēia no ka mea ua kaumaha loa ia, a ʻaʻole lawa ka ikaika o kona mau wāwae e neʻe i kona kino ikaika.

Ua kaumaha nā forelimbs o Ichthyostega a ʻaʻole hiki i ka forearm ke hoʻolōʻihi piha. ʻO nā mahele o ka sila elepani ka hoʻohālikelike anatomical kokoke loa i waena o nā holoholona ola. Ua piʻi paha ʻo Ichthyostega i nā kahakai pōhaku, e neʻe ana i ka forelimbs i ka like a kauō i nā lālā hope me ia.

ʻAʻole hiki i ka holoholona ke hele ma ke ʻano tetrapod maʻamau no ka mea ʻaʻohe i ka forelimbs ka pae i koi ʻia o ka neʻe rotational. Eia naʻe, ʻaʻole maopopo ka nohona kikoʻī o Ichthyostega ma muli o kāna mau hiʻohiʻona ʻano ʻē.

ʻO ke kūkulu kaiāulu a me ka hana hou

Kiʻi: Ichthyostegai

Manaʻo ʻia ua hoʻohana nā ichthyostegs a me kona mau hoahānau i ka manawa i ka lā e hāpai i ka mahana o ko lākou kino. Hoʻi pū lākou i ka wai e hōʻalili, ʻimi holoholona, ​​a hānau kope. Ko lākou nohona koi ikaika forelimbs e huki ma ka liʻiliʻi o ka wai, a me ka ikaika ribcage a me ka iwi kuamoʻo e kākoʻo iā lākou, ʻili ma ko lākou ʻōpū e like me nā crocodiles o kēia manawa.

Mea hoihoi: Ua lilo ʻo Ichthyostegs i mau kūpuna o nā lālā nui ʻelua o nā amphibians, ʻokoʻa i ke ʻano o ka iwi poʻo a me nā lālā. I ka Late Devonian, kū aʻe nā labyrinthodonts. Ma waho, ua like lākou me nā crocodiles a i ʻole nā ​​salamanders. I kēia lā, ua ʻike ʻia nā haneli he nui o nā labyrinthodonts, e noho ana i nā ulu lāʻau a me nā kahawai.

He koi koi ka wai no ka ichthyostega, ʻoiai ʻaʻole hiki i nā hua o nā tetrapods terrestrial terrestrial ke ola ma waho o ka wai, no laila ʻaʻole hiki ke hana hou me ka ʻole o kahi wai. Pono ʻia ka wai no kā lākou larvae a me ka hoʻoulu ʻana i waho. Mai ia manawa, ua hoʻomohala ka hapa nui o nā vertebrates terrestrial i ʻelua mau ʻano hana o ka hoʻoulu ʻana i loko. E kuhikuhi pololei paha, e like me ka mea i ʻike ʻia ma nā amniote āpau a me kekahi mau amphibians, a i ʻole kuhikuhi ʻole ʻia no nā salamanders he nui, e kau ana i kahi spermatophore ma ka honua, a laila hāpai ʻia e ka wahine.

ʻEnemi kūlohelohe o ichthyosteg

Kiʻi: he aha ke ʻano o ka ichthyostega?

ʻOiai ʻaʻole kūkulu hou ʻia nā forelimbs no ka mea ʻaʻole i loaʻa iā lākou i nā fossil o ka holoholona i ʻike ʻia, manaʻo ʻia ʻoi aku ka nui o kēia mau appendage ma mua o nā hindlimbs o ka holoholona. Manaʻo nā kānaka ʻepekema ma kēia ʻano neʻe ka ichthyostega i kona kino mai ka wai a i ka ʻāina.

Me he mea lā ʻo ka locomotion, kahi hana o nā neʻe instinctive o ka ʻōnaehana musculoskeletal o ke kino, ʻo ia wale nō ka loli iki o ka neʻe ma lalo o ka wai e hoʻohana ana i kahi hui o ka huelo a me ka neʻe o ka wāwae. I kēia hihia, hoʻohana kūikawā ʻia nā wāwae no ka hele ʻana o nā mākala ma o ka ulu ʻana o ka wai i kanu ʻia i nā wai.

ʻOiaʻiʻo hoihoi: ʻOiai hiki ke neʻe i ka honua, ua ulu ʻo Ichthyostega i ke ola i loko o ka wai, keu hoʻi i ka wā o nā mākua o kona ola. ʻAʻole neʻe iki i ka ʻāina, a ʻo ka liʻiliʻi paha o nā ʻōpio, i ʻae iā lākou e neʻe maʻalahi i ka ʻāina, ʻaʻole i lawelawe no ka ʻimi ʻana i nā meaʻai ma waho o ka wai, akā he ala e pale aku ai i nā mea ʻino nui ʻē aʻe a hiki i ka ulu ʻana a lawa ʻole e lilo i kā lākou mea pio.

Kuhi nā kānaka ʻepekema ua hāʻawi ka holomua ma ka ʻāina i nā holoholona me ka palekana nui aʻe mai nā mea ʻino, hoʻemi iki i ka hoʻokūkū, a me kekahi mau pōmaikaʻi o ke kaiapuni i loaʻa ʻole i loko o ka wai, e like me ka oxygen oxygen a me ka mālama ʻana i ka mahana - e hōʻike nei i ka hoʻomohala ʻana o nā lālā e hoʻololi hoʻi i ka hana. hapa o ko lākou manawa mai ka wai.

Eia naʻe, ua hōʻike ʻia nā noiʻi ua hoʻomohala nā sarcopterygs i nā lālā like me ka tetrapod kūpono no ka hele wāwae maikaʻi ʻana ma mua o ka hele ʻana i ka ʻāina. Hōʻike kēia ua hoʻololi lākou e hele wāwae ma ka ʻāina ma lalo o ka wai ma mua o ka neʻe ʻana i ka ʻāina.

Heluna a me ke kūlana o kēia ʻano

Kiʻi: ʻIchthyostega

ʻO Ichthyostega kahi ʻano i pau i ka lōʻihi loa. No laila, paʻakikī i kēia lā e hoʻokolokolo i ka nui o ka lehulehu o Ichthyostega ma ka Honua. Akā ʻoiai nā fossil i loaʻa wale i loko o Greenland, mea liʻiliʻi paha ka nui o kēlā me kēia. Ua noho kēia mau holoholona i kahi manawa paʻakikī loa. Ua luku ʻia kahi mea nui i ka hoʻomaka ʻana o ka pae hope loa o ka Devonian, ʻo ka holoholona o nā waihona Famenzian e hōʻike ana ma kahi o 372.2 miliona mau makahiki i hala aku nei, i ka wā i nalowale ai nā iʻa fossil āpau, koe wale nō nā heterostracic psammosteids, nalowale koke.

ʻO ka Late Devonian extinction kahi o nā hanana make ʻelima i loko o ka mōʻaukala o ko Honua ola, a ua ʻoi aku ka radical ma mua o ka hanana make e like me ka mea i pani i ka Cretaceous. Ua loli ka hopena o ka Devonian Extinction Crisis i ke kaiāulu kai a pili i nā meaola pāpaʻu i ka wai mehana. ʻO ka hui nui i ʻeha mai kēia hanana luku aku nā mea kūkulu o nā ʻōiwi papa nui.

Aia ma waena o nā hui kai kū nui i:

• nā brachiopods;
• ʻAmona;
• trilobite;
• akritarchs;
• iʻa ʻaʻohe aʻa;
• konatona;
• nā placod germ āpau.

ʻO nā mea kanu terrestrial, a me nā ʻano wai hou e like me ko mākou mau kūpuna tetrapod, ʻaʻole i hoʻopilikia ʻia e ka hanana Late Devonian extinction. ʻAʻole ʻike ʻia nā kumu o ka luku ʻia o nā laha i ka Late Devonian, a noho kahakaha nā wehewehe ʻana āpau. I kēia mau kūlana ichthyostega ola a hoʻonui ʻia. Hoʻololi nā hopena asteroid i ka ʻili o ka Honua a hoʻopili i ka poʻe e noho ana.

Lā paʻi: 08/11/2019

Lā hou: 09/29/2019 ma 18:11