Week8.1 - Biotic Interchange Introduced species Natural...

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Biotic Interchange Introduced species • Natural colonization and merging of biotas resulting from plate tectonics – Fossil record yields information, but may be sketchy • e.g., what happened to the Gondwanan biota in India? • Human-mediated introductions give insight to what happens when isolated biotas come into contact – Colonization of polynesia – European explorations of 1600-1800 – Canal building Lack of fossil studies paints an incomplete picture of what happened after India crashed into Eurasia. Prevailing hypothesis is that the larger and more diverse biota of Eurasia had higher success rate of migration and speciation compared to the Gondwanan biota. More on the Great American Interchange • Fossil records of non-volant mammals from North and South America for past 10 my reveal: – Diversity of N. American fauna remained unchanged at generic level – Diversity of S. American fauna increased as northern groups established in the south • rabbits, squirrels, dogs, bears, raccoons, weasels, cats, deer, peccaries, tapirs, camels, mastodons, horses • half of contemporary species are derived from N. Am ancestors; only 10% of N. Am spp have S. Am ancestors – Many S. American endemics went extinct • Marsupial carnivores
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More on the Great American Interchange • Pattern for vertebrates other than non-volant mammals is different – Birds, bats, reptiles better dispersers across water than non-volant
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This note was uploaded on 07/17/2008 for the course EEOB 700 taught by Professor Wolfe during the Winter '05 term at Ohio State.

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Week8.1 - Biotic Interchange Introduced species Natural...

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