BIOL211 Study Guide - Amnion, Dermal Bone, Dentin
Document Summary
Active running animal limb anatomy fewer dinosaurs (predators) than prey stable isotopic composition is consistent with high body temperatures. No elaborate nasal bones to conserve moisture and heat. At least 5 mass extinctions during vertebrate evolution. Most severe was end of permian era (250 mybp) Eutherians are placental mammals in uterus (i. e. shrew) Metathera are marsupial mammals in pouch (i. e. opossum) Eutherians originated in eurasia and displaced marsupials invated south america late and never made it to antarctica / australia until introduced there by humans. Gastrulation (blastocoel) invagination, creates endoderm and ectoderm with mesoderm in middle (on dorsal part of endoderm) Blastula complete, markedly unequal divisions larger cells on one side (vegetal pole), blastocoel towards animal pole. More yolk, bastula is several cells thick, small blastocoel. Gastrocoel highly modified to accommodate all the yolk splitting of coelom instead of evagination.