The Great American Biotic Interchange: Patterns and Processes Author(s): S. David Webb Source: Annals of the Missouri Botanical Garden, Vol. 93, No. 2 (Aug., 2006), pp. 245-257 Published by: Missouri Botanical Garden Press Stable URL: http://www.jstor.org/stable/40035724 . Accessed: 08/04/2014 23:14 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact
[email protected]. Missouri Botanical Garden Press is collaborating with JSTOR to digitize, preserve and extend access to Annals of the Missouri Botanical Garden. http://www.jstor.org This content downloaded from 137.111.226.20 on Tue, 8 Apr 2014 23:14:05 PM All use subject to JSTOR Terms and Conditions THE GREAT AMERICAN BIOTIC S. David Webb2 INTERCHANGE: PATTERNS AND PROCESSES1 Abstract Whenthe Panamanianland bridgewas emplacedabout 2.7 Ma, it triggeredthe GreatAmerican Biotic Interchange(GABI), a major mingling of land mammal faunas between North and South America. Four families of northern immigrants (Procyonidae,Felidae, Tayassuidae,and Camelidae)diversified at moderaterates, while four others, Canidae, Mustelidae, Cervidae, and especially Muridae, evolved explosively. As a consequence, half of living South American genera are descendantsof northernimmigrants. The other major consequence of the interchangewas the conquest of tropical North Americaby immigrantsfrom Amazonia, an episode that justifies the term NeotropicalRealm.