Darwin's Finches Today
Between two and three million years ago, one or more stray South American finches landed on the Galápagos Islands, hundreds of miles to the west of the mainland. Over time, the colonizers and their descendants adapted to new habitats and food sources--and a new species emerged, the Galápagos finch.
In most groups of organisms, the formation of new species begins when geographically separated populations evolve in different directions. Indeed, isolated islands like the Galápagos are natural "laboratories" of evolution--their seclusion and range of habitats drive new species to form. Eventually geographic barriers may break down or be overcome, and related--but distinct--species may come back into contact. Today, 14 finch species live on the Galápagos, a few on each major island, all products of an intricate evolutionary history
Isolated islands are often home to animals unknown anywhere else in the world, such as Komodo dragons on Komodo Island, birds of paradise around New Guinea, and lemurs on Madagascar and neighboring islands.