by Mark Hopkins

Created on: June 02, 2007

The Galapagos Islands lie isolated in the Pacific ocean about 600 miles off the coast of Ecuador. There are 13 major islands and the variety of species' adaptation helped Charles Darwin formulate his theory of Evolution by Natural Selection.

Being so isolated from the mainland, many Galapagos species descend from a small stock of ancestral animals which made landfall on the islands by chance.

It is noticeable that as the original species' descendants moved from one island to the next they tended to acquire certain changes to their anatomy which fitted them to cope with the challenges specific to their new island. When some of them moved to yet another of the Galapagos Islands, yet more adaptation would take place.

This process is what is meant by Adaptive Radiation; as descendants of a species radiate out from the original home, with its particular challenges, they meet new circumstances and their anatomy or behavior alters to maximize their chances of surviving and reproducing in the new environment. It can be seen particularly well amongst the various Finch species which inhabit the Galapagos islands. Eventually entirely distinct species can evolve, slightly different from each other but clearly all descended from a common ancestor.

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