Islands Good Places to Vacation and Speciate

Some places are just plain better for speciating and studying speciation than others — islands, for example. As stated earlier, islands are just tailor-made for allopatric speciation via founder events.

Islands can be hot spots for speciation. Hawaii is a good example. So are the Galapagos Islands, where Darwin got his first insights into the process of speciation by natural selection. Two factors combine to make islands areas that can facilitate speciation:

1 Isolation: Islands are by definition places where populations are isolated from the rest of the species. As gene flow is low, opportunities for genetic diversification increase.

1 Potential for subsequent speciation: After a species has evolved on one island in a chain, some of its members can blow or drift to another island, where they may diverge further. In the future, some of them may be blown back to the first island — where, if they're different enough, they may diverge from the population on the original island to produce a second new species.

Islands aren't populated solely by species that just happen to wash up on their shores or get dumped there by a wayward breeze. If an archipelago is far enough from the mainland to make colonization from mainland organisms unlikely, the island is often populated by the species that are unique to the island. You can safely assume that these species arose via speciation on the island. Hawaii, for example, has several native species (like ukulele players) that don't exist anywhere else. They arose in the Hawaiian archipelago.

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