BIOL10003 Lecture 12: Human Evolution
21 Jul 2018
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Human brains became larger as jaws became smaller. Prototherians: produce eggs and milk to feed young. Therian: marsupials - produce young inside mother to a relatively small stage and comes out and sits in pouch. Young continues to develop while it feeds on milk and grows. Eutheria(cid:374): e. g. whales, (cid:271)ats (cid:271)e(cid:272)a(cid:373)e (cid:272)o(cid:373)(cid:373)o(cid:374) after a huge (cid:373)eteor stru(cid:272)k the earth that wiped out other animals. Small mammals survive because they were able to hibernate. Mammals evolved from a separate group of reptiles. Became dominant after meteor wiped out all animals > 25kg (65 mya, cretaceous > tertiary) Single jaw bone, and bones to amplify sound in the ear. Endothermic - with hair / fur insulation, sweat glands. Enzymes in the body are tuned to a specific temperature so that they can work efficiently. No mixing of deoxygenated and oxygenated blood, hence very efficient oxygen transport. Most mammals: a placenta to feed the young in the mother.
