GEO 103 Lecture 33: Mammals
28 Apr 2017
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Document Summary
Predator diets are in fact complex - some pure carnivores (eg cats), others omnivores (eg bears) Most have well-developed canine and carnassial teeth for slicing meat. High on food chain so < 5% of population and fossils rare. Order artiodactyla (even-toed most common) and perissodactyla (odd-toed - common in early cenozoic) Creatures often require speed, accounting for long slender limbs providing long stride. All are herbivores - divided into grazers (grass) and browsers (leaves, shrubs, etc) Grazers have specially evolved teeth (cemented high crowns) to minimize effects of sand/soil abrasion. Horse evolution provides exceptionally good examples of intermediaries. Elephants are example of mammals with long snout - order proboscidea. Mastodons evolved during miocene and survived until just few thousand years ago. Whales, part of order cetacea, include largest animals to ever live. Blue whales up to 30 m long and 130 tonnes. Transition from land to aquatic involved loss of rear limbs and conversion of fore limbs to paddle-like flippers.
