Bridging the Americas: The Great American Biotic Interchange
For millions of years, North and South America existed as isolated landmasses, separated by a vast oceanic expanse. Each continent evolved its own unique assemblage of species, shaped by distinct environmental pressures and evolutionary pathways. However, approximately 3 million years ago, a transformative geological event changed the course of biological history across both continents: the formation of the Central American Isthmus created a permanent land bridge, triggering one of the most spectacular mass migrations in Earth's history.