It begins with charles darwin who wondered about the

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Unformatted text preview: who wondered about the evolutionary history of whales. They clearly were mammals who had to breathe air. They were like seals and otters and walruses which were specialized to live in the water. But whales were the most specialized of the group How had they evolved? If their ancestors were land mammals, we should expect that there were many transitional steps between the land ancestors and today’s whales. Those transitional species were missing until NOW. Whale Evolution Whale Phylogeny Whale Terrestrial Amphibious Aquatic Whale Phylogeny Whale Terrestrial Amphibious Aquatic TRENDS IN WHALE EVOLUTION EVOLUTION Whale Nostrils Whale End of snout Middle of snout Top of head (Blowhole) Loss of Legs Loss Ambulocetus 50 mya Basilosaurus 37 mya Sperm Whale Today Basilosaurus leg skeleton Basilosaurus Evolution of Whale Ears Whale Ambulocetus hears through ears directly Basilosaurus vibrations transmitted by vibrations lower jaw to middle ear lower Modern toothed whale Ecolocation-melon directs Ecolocation-melon sounds & lower jaw receives echoes receives Whale Evolution Whale Old Idea Based on anatomy New Idea Based on DNA...
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This note was uploaded on 11/21/2013 for the course BIO 200 taught by Professor Herreid during the Fall '07 term at SUNY Buffalo.

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