gel_lec_21

gel_lec_21 - -Sabertooth (2-3 different lineages in true...

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Lecture 21 – 3/3/10 Cenozoic Mammals What are the major mammal groups? / How far can they be traced back? Monotremata Marsupialia (fossil record leads back to Cretaceous, age of dinosaurs) Placentials (boundary between Mesozoic and Cenozoic) Three living groups traced back to the early Paleocene - Insectivora - Carnivora - Primates Late Paleocene appearance - Lagomorphs (rabbits) - Dermoptera - Rodentia - Xenarthra End of Paleocene (Hoofed Mammals) - Perissodactyla (odd-toed ungulates) - Artiodactyla (even-toed ungulates) Eocene and later mammals - Afrotheria - Scandentia What replaced dinosaur behavior? The hoofed mammals replaced them. - Eocene (warm) – odd-toed mammals - Oligocene (cold, larger species evolve) – odd-toed mammals - Miocene (slightly warmer) - Pliocene - Pleistocene (getting into ice age) What are the repeated themes? - Long, narrow, picking beak or finger
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Unformatted text preview: -Sabertooth (2-3 different lineages in true cat family; nimravid closely related; masrsupials even had sabertooth)-Moles (burrowers)-Gliders (rodent, squirrel, lemur)-Lion and marsupial lions-Tasmanian wolf (and dog very similar, marsupial vs. placential: 4 incisors in tas wolf to 3 in dog, 3 molars in dogs; marsupials have palatal vacuities; carnivorans have carnassials) Was horse evolution directional? Todays horses have hypsodonty teeth. Enamel goes deep into the bone; the enamel gives rise to ridges that help grind down grasses and can last longer. Toes started from 5, went to 1 (a hoof). The first horse was tiny, evolved into much bigger. (5-toed small with simple teeth 1-toed large with complicated teeth). Overall, horse evolution is RANDOM evolution....
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gel_lec_21 - -Sabertooth (2-3 different lineages in true...

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