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Unformatted text preview: invoke Both vicariance and dispersal to account for distributions (not always in the same instance). Example: Galapagos finches had to have dispersed to the archipelago from the mainland and in so doing imposed a vicariance event on themselves. South American land bridge when sea levels dropped in the Pliocene the isthmus of Panama rose and served as an avenue of dispersal for terrestrial mammals (the "Great American Interchange" where unique N.American mammals dispersed to S. America and unique S. Amer. mammals moved north, 3 mil. years ago; see fig. 18.14, tables, 18.2, 18.3, pgs. 528-529), but served as a vicariance event for marine life that was distributed in the region. Lead to the formation of Geminate species (species pairs on either side of the isthmus who are each other's closest relative and were probably one species before the sea level dropped)....
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This note was uploaded on 11/06/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.
- Fall '10