Thaum ntxov tshaj plaws tsis muaj teeb meem gastropods hnub tim los ntawm Lub Sij Hawm Cambrian, ncig 500 lab xyoo dhau los Ib txhia paleontologists xav tias gastropods tseem laus dua, raws li cov pob txha mos me me hu ua Aldanella, paub. Los ntawm Lower Cambrian pob zeb, tab sis lwm tus xav tias Aldanella yog kab cab.
Lub sijhawm twg Gastropoda chav kawm thawj zaug tshwm sim hauv ntiaj teb?
Gastropods thawj zaug tshwm sim hauv cov ntaub ntawv pob txha thaum lub sijhawm Cambrian thaum ntxov, kwv yees li 550 lab xyoo dhau los. Cov tsiaj sib txawv no yog tus cwj pwm los ntawm lub cev mos, ua los ntawm peb qhov tseem ceeb: lub taub hau, ko taw, thiab visceral loj.
Thaum twg gastropods ploj mus?
Ntau lub gastropod taxa tau ploj mus thaum lub sij hawm the Late Cretaceous. Cov stratigraphic ranges ntawm 268 genera tso cai los tsim kom muaj lub neej ntev ntawm extinction neeg raug tsim txom rau txhua theem ntawm lub sijhawm no.
Npauj npaim gastropod yog dab tsi?
Cov pob txha loj tshaj plaws yog tshaj 500 lab xyoo. Fossil gastropods tuaj nyob rau hauv tag nrho cov duab thiab ntau thiab tsawg. Cov molluscs tau muab faib ua ntau pawg - gastropods, bivalves thiab cephalopods.
Nqaij thawj zaug tshwm sim?
Snails 'cov poj koob yawm txwv yog ib hom tsiaj uas paub ntxov tshaj plaws hauv ntiaj teb. Muaj cov pov thawj fossil ntawm cov thawj coj gastropods yos rov qab mus rau lub sijhawm Cambrian lig; qhov no txhais tau tias lawv nyob ze li ntawm 500 lab xyoo dhau los.