North and South America Connection Surprisingly Recent
North and South America's relatively recent land connection is changing what is known about the ecology and evolutionary biology of the continents.
A comprehensive review of studies concluded that the Isthmus of Panama is a recent development in geological time. The land bridge connecting North and South America is a mere 2.8 million years old as opposed to the 6 to 23 million years hypothesized and supported in other papers.
"Our study had the simple aim of refining the timing of isthmus formation in a format intelligible for a wide audience of interested scientists, including geologists, ecologists, paleontologists, climatologists and evolutionary biologists, each of whom were begging for clarification of the question," staff scientist at the Smithsonian Tropical Research Institute (STRI) in Panama and the lead author of the study Aaron O'Dea told Live Science.
Though the formation of the Isthmus of Panama did begin forming 30 million years ago, the land bridge didn't appear until a drop in sea level combined with a geologic uplift. Evidence to support the theory of a more recent formation of the land bridge was found by analyzing family trees of shallow water marine animals, deep ocean sediments and massive migrations of land animals.
Results of this review have implications for understanding species evolution. North and South America connect to allow land access between the continents and to separate the Pacific and the Caribbean Sea.
The current body of knowledge about land and sea life surrounding the Isthmus of Panama and across the Americas has been called into question. Scientific understanding regarding the evolution of these species hinges on knowing the age of the formation.
Evidence for the recent connection of North and South America is strong, but still not definitive. Scientists will continue working together to find additional evidence supporting the modern age of the land connection.