A recent study says that many of the plants and animals that call Latin America home may have had their roots in the Amazon region.
The study, co-authored by Harvard Visiting Scholar Alexandre Antonelli and an international team of researchers, says that a dynamic process of colonization and speciation led to the formation of the American tropics, which is the most species-rich region on the planet. The study is described in a paper published in the Proceedings of the National Academy of Sciences.
“We were astonished to detect so much movement across such different environments and over such large distances,” said Antonelli, the study’s lead author. “Up until now, these natural dispersal events were assumed to be quite rare. Our results show how crucial these events have been in the formation of tropical America’s unique and outstandingly rich biodiversity.”
Over tens of millions of years, thousands of species have naturally made their way to new regions, where some of them survived and adapted to new conditions. These adaptations added up, and when the offspring were sufficiently different from earlier generations, new species were formed. Over time, this dynamic process occurred so many times in the American tropics that the area became the exceptionally diverse region seen today.
To understand that process, Antonelli and colleagues used information on the evolutionary relationships, distribution, and timing of the origin of thousands of tropical species to calculate how often species dispersed into new regions or new environments. Much of this information came from natural-history collections, including specimens at Harvard University Herbaria and the Museum of Comparative Zoology, where Antonelli is currently working.