Mammalian evolution and the great American interchange
LG Marshall, SD Webb, JJ Sepkoski Jr, DM Raup - Science, 1982 - science.org
A reciprocal and apparently symmetrical interchange of land mammals between North and
South America began about 3 million years ago, after the appearance of the Panamanian
land bridge. The number of families of land mammals in South America rose from 32 before
the interchange to 39 after it began, and then back to 35 at present. An equivalent number of
families experienced a comparable rise and decline in North America during the same
interval. These changes in diversity are predicted by the MacArthur-Wilson species …
South America began about 3 million years ago, after the appearance of the Panamanian
land bridge. The number of families of land mammals in South America rose from 32 before
the interchange to 39 after it began, and then back to 35 at present. An equivalent number of
families experienced a comparable rise and decline in North America during the same
interval. These changes in diversity are predicted by the MacArthur-Wilson species …
