Where nekukudziridza mammalian mudumbu? kunyanya mhuka

Mhuka (7 kirasi kudzidza nyaya iyi iri chikamu Zoologie) sangana zvose mhuka kuti zvokudya vadzo nomukaka. Sezvo izvi mukirasi kupfuura vertebrates, pane classifications wandei mukati ichi hurongwa kubatana. Mumwe wavo inobva kupi mammalian mudumbu. mubvunzo uyu isu Funga zvakadzama munyaya ino.

mammalian mhando

mhuka dzose imhuka dioecious dzakakwirira. Uye nhunzvi, uye varume vane aiwanzopiwa wokushanda gonads: asi ovaries uye testes, ukuwo. Dzinondishamisira outwards unyanzvi makwara. Nokuti mhuka dzose idzi maitire chete munyika muchangosangana. Zvisinei, kubvira apo kukura mammalian mudumbu kunobva paumbwe dzaro pakuzadzisa pamwero.

Ndivanaani yinotheria

Strange asi zvechokwadi: kune mhuka kuti mazai. Vari kunzi "yinotheria" uye anoumba rimwe chete chikwata - monotremes. Zvino zita nokuti mhuka idzi vane cloaca. Uyu chinyakare unhu, yo yapfuura chordates. The cloaca iri buri chete umo zvigadzirwa Munokudzwa Exchange Urinary, zvomudumbu uye dzokubereka nehurongwa.

Yinotheria vashoma kwazvo nhamba, zvinosanganisira mhando 6 chete. nzvimbo dzavo - Australia pamwe pedyo zvitsuwa. Vamiririri dzavo ndidzo echidnas, platypus uye akasiyana spiny Nehwiribidi. Havana minyatso uye mukaka kuburikidza ducts ari mumasero ukasunungurwa kuti pose ganda. The Cubs kuti kunanzva nayo, kuti vagute.

Zvikuru zvechienzi ndiye chitarisiko izvi mhuka. Echidna zvakafanana zvikuru hombe tyoni. Its refu uye unopinza tsono haisi chinhu asi nadzurudzo bvudzi zvinozivikanwa mhuka dzose. Below wavo paiva nguvo batana. Uye kana iwe funga nezvokuti pamberi chikamu tomu iri elongated muna proboscis uye maoko nemakumbo yakapinza nenzara rakagadzirirwa uone, echidna uye kuyeuchidza tarenda chisipo mhuka. munhukadzi yavo unobereka imwe zai. Vakanyatsoongorora kuchengetedza nayo iri mipendero ganda iri ventral divi muviri.

Platypus anotarisa zvakasiyana. By kwayo rokuremekedza zvikuru nyore zvokufungidzira kuti ine paupamhi uye sandara mhino. On minwe akaronga kushambira Kamudzira, uye muswe ane flattened chimiro, kuita flippers. Platypus Vanochochonya mazai avo matendere, iyo inoenderana pachavo.

Izvi mhuka Subclass

Mhuka idzi dzine zvakafanana ndechokuti yadzinobereka kurarama vaduku kamwe, kwete kuti hatch kwavari, sezvinoita shiri. Havana cloaca, uye ducts ari zvomudumbu, okubereka uye Urinary hurongwa kuzarura vakaparadzana, unyanzvi zvengarava. Zvichienderana apo mammalian mudumbu, kusiyanisa marsupials uye placental mhuka.

Marsupial kukupfura

Ndizvo zvakafanana vagere kondinendi Australian. Ivo vanoonekwa ne chokwadi kuti nzvimbo dzichiri mammalian mudumbu (zai), vanosiya nokukurumidza. Izvi nokuti zvachose kupotsa placenta. Somugumisiro, vechiduku vanoberekwa saibva, diki kukura, uye kwete vanokwanisa akazvimirira upenyu. Pashure kuberekwa imwe nguva vari bhegi ganda, uyewo rakamiswa pamusoro ventral divi muviri. It akazarura uye ducts ari mammary mumasero.

A achangoberekwa simba zvokuti uye vasingabatsiri kuti yokutanga nguva havatombozivi muchayamwa hwavo. Tsandanyama mumasero nomuzvarirwo ipfupi uye yaibva spurting mukaka inopisa kupinda mumuromo marsupial mhuka duku. Vamiririri mhuka idzi anonyanya kangaruru. Vanokwanisa kufamba ari kumhanya anenge 60 km / h.

Zvakajairika Australia ndiro marsupial nebere koalas uye possums.

Placental makavigwa mammalian mudumbu

The budiriro mukuru, uye nokudaro kupararira mhiri nyika, akatambanudza mhuka, pamwe dumbu, iyo inogadzirwa panguva yepamuviri yacho placenta. It anosunga amai mwana panguva yepamuviri. Yatangwa tsinga rinoitwa afemeruke uye inotonhorera exchange. Somugumisiro, muviri ramangwana anopiwa okuti zvose zvinokosha uye ezvinhu, uye uterine rusvingo kudzivirirwa kubva ezvinhu ipa zvakatipoteredza. Akawana simba zvakakwana kuva pakarepo pashure kuberekwa musoro uye pashure pfupi kuenda chinozvimirira. Sei mberi unhu ichi, rinoti nhamba uye chinzvimbo chikuru mhuka muviri kuti. Insectivores, zviremwaremwa, nemakonzo, Lagomorphs, Artiodactyla namabhiza, carnivores, pinnipeds - ichi hachisi gurupu vezvikwata zviri placental. Hongu, uye primates, izvo zvinosanganisira ano akacherekedza Homo sapiens, yakasvika ayo kukura nemhaka pamberi ichi chinhu uyewo.

Kunyanya mhuka: zvakanakira nekuipira

Chokwadi, kukura embryo iri dumbu nomukombiyuta placenta ndiyo nzira inonyanya akakwana. Nechepakati inotungamirwa uterine rusvingo uye blastoderm zvakasimba fused. The placenta ose zvinhu zviri muviri raamai vari zvifambiswe muMutumbi mwana. Mudumbu akanga asingatyi upi tembiricha kuchinja, kana makororo. Sezvingatarisirwa, oviparous vari zvishoma zvakanaka chinzvimbo. Iri pachena. Chokwadi, mazai ane yakawanda zvinovaka muviri zvakakodzera kukura embryo. Asi ivo vave anodiwa dzamakondo zvikara. Uye kufunga kuti kufadza nhamba mazai 3-4, unogona kazhinji kusiya pasina mwana. Young marsupials vanoberekwa zvakare underdeveloped. Somuenzaniso, nguva yose pamuviri kwacho possum kwangopera vhiki mbiri. Sezvingatarisirwa, zvakadaro pfupi nguva muviri kunzwisisa kwakadaro haana nguva kusvika zvakakodzera Danho okukura.

Saka, kukura mhuka ine zvinhu kubvumira chokubatanidza vave mapoka matatu, imwe neimwe ine yayo kwadzakabva zvinhu: monotremes, marsupials uye placental.