Mhuka: tsanangudzo pfupi

To musi, mhuka vanoonekwa kuti chimwe zvemberi makirasi. boka iri dzinoratidzwa dzinokosha zvinhu. Maererano nokumwe kufungidzira kuti anozivikanwa zvidzidzo munyika nhasi kune vanopfuura zviuru zvishanu veboka. Kunyange zvinokosha kuziva kuti nhamba iri anofungidzirwa chaizvo, nokuti vasayendisiti uye vari kutsvaka zvitsva mhando zvevakomana.

Mhuka uye kuparadzirwa kwavo

Mhuka vanoonekwa kuti zvikuru nemamwe vamiririri fauna of. Vari anoparadzirwa munyika yose.

Vamiririri mukirasi iyi inogona kuwanika anenge ose makuru nzvimbo Pasi. Hadzina zvisikwa dzakanaka kuchipisa gwenga okunze ari Highland munharaunda. Unogona kuona navo polar nharaunda uye inopisa anofukidza. Dzakakurumbira kunyange hwemvura zvakatipoteredza.

Zvichida chete munzvimbo dzisina ine mhuka dziri mukati nyika Antarctica uye yakadzika chikamu mumakungwa.

Sezvineiwo, nzvimbo kuparadzirwa monotremes mhuka (semuenzaniso, kuti platypus) zvakajeka chete nzvimbo New Guinea uye Australia. Marsupials vamiririri anoparadzirwa pazvitsuwa Oceania, uyewo Australia uye munharaunda dzeAmerica. Chimwe dzinonakidza ndechokuti pamusoro kondinendi Australian yaigarwa mashomanana placental mhuka vasati vasvika vokutanga kugara.

Mhuka: huru zviri mukirasi

Sezvambotaurwa, iyi boka mhuka ine zvakawanda nemamwe maitiro, achiratidza yakakwirira pamwero sangano:

• Anenge viviparous mhuka.
• Vakadzi achayamwisa mukaka wavo muduku anogadzirwa chaiyo mumasero (nenzira, nokuda chokwadi ichi mhuka kuwana zita ravo).
• Vamiririri Kirasi vane chaiyo romusoro, kuita sebaceous uye ziya mumasero.
• Nokuti vanonzi nezvekumwe mammalian homeotherms, kana ushamwari-ropa rechiJudha chairo - zvavo tembiricha muviri hakunei mamiriro ezvinhu uye ambient tembiricha.
• A zvikuru chinokosha boka iri mhuka itsime kunyatsobudirira uropi, kunyanya, chikamu chokupedzisira chacho. Heino musimboti panopinda vamiririri sevanonyanya zvikuru kunzwisisa nemaitiro.
• In mhuka akaumba auricle, kuruvanze nzeve canal, uyewo zvose matatu auditory ossicles, izvo, sezvinei, vari dzakachinjwa mandible.
• Nokuti veboka vanoonekwa ne yepamusoro mana chambered mwoyo uye kuruboshwe kutsemuka chematenga, izvo zvinopa kuparadzana ropa riri venous uye arterial (somuenzaniso, zvinokambaira uye venous arterial ropa yakavhenganiswa mumwoyo).
• A nevamwe chinhu anogona kunzi uye alveolar nemamiriro mumapapu.
• Uyezve, pane kusiyana maumbirwo masero eropa - masero matsvuku eropa remhuka idzi dzisina nuclei, munhu kufema ruvara.
• Mhuka vane vertebrae manomwe remuromo nharaunda.
• For nhengo dzekirasi ichi vari dzinoratidzwa mhando mazino (kuvapo incisors, canines, molars). Kana ichi Via mazino nemidzi achinyatsotaurira shaya mafupa.

Mabviro mhuka

Masayendisiti anodavira kuti madzitateguru mhuka ano vaiva zvinokambaira kuti akazviratidza muna Paleozoic. mhuka idzi uchiri zvimwe kufanana pamwe amphibians, kunyanya pamberi ganda omumuviri uye zvichida kaviri occipital condyle.

Zvikurukuru pedyo nehama ano mhuka-zvakadai zvipenyu vanoonekwa. Vamiririri boka iri vakanga dzinoratidzwa kuvapo zvakasiyana mazino (molars, incisors uye canines). Okumusoro ezasi shaya Vakabatanidza pfupa chaiyo iyo yakatanga kupinda mammalian auditory ossicles. Asi vamiririri mhuka-kufanana yakatotsakatika muna Upper Triassic.

Nechekare ari Jurassic nguva, pakanga kuparadzana rokupupurira mhenyu-rudzi kubva kune nhengo kuti vakaisa mazai.

Kutaura zvazviri, kuzoumba zvakajeka dzidziso kwakabva mhuka hazvibviri, nekuti kusvikira zuva rino, paleontologists nezvimwe masayendisiti vachishingaira tsvakurudzo munharaunda iyi.