Roughly 3 million years ago, a spectacular natural experiment began when the Isthmus of Panama finally closed, a geologic process that began many million years earlier. On land, the formation of the Isthmus connected North & South America, and ushered in one of the greatest episode of migration in earth’s history— The Great American Biotic Interchange—Many of the mammal species we see today arrived during this event. However, what was a bridge on land became a barrier in the ocean. Where once a single tropical ocean flowed, two distinct marine environments formed when the Isthmus closed. Strikingly different physicochemical conditions persist in these two oceans today & these differences are reflected in the communities adapted to live there. So for marine organisms the story unfolded quite differently. The barrier separated populations, leading to speciation for some & local extinction for many others.
Cite button above to access a BibTeX formatted bibliography for literature used in researching & preparing this presentation. The
video button links to an awesome video on the rise of the Isthmus by the STRI storytellers.