Unformatted text preview: -Therians: placental, live birth (all other mammals) Prototherians such as duck-billed platypus and echidnas lack a placenta, lay eggs and have sprawling legs. Therian clade has two subdivisions:-Marsupials: carry and feed young in a ventral pouch. Young are born after short gestation, and crawl into pouch for further development (long lactation).-Eutherians- placental mammals. Young are more developed at birth. (longer gestation, shorter lactation). Diversity among the eutherians:-Rodents are most abundant.-Bats evolved flight. -Aquatic whales and dolphins evolved from even-toed hoofed mammals (hippos, deer).-Primates radiated from a small, arboreal, insectivorous mammal. Ectothermy vs. endothermy: INSERT IMAGE OF ECTO VS ENDO...
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- Spring '08
- Biology, mammary glands, even-toed hoofed mammals