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Lizard Evolution

May 12, 2008

Lizards introduced to a new island undergo extremely rapid evolution.


Evolution speeds up. I’m Bob Hirshon and this is Science Update.

Charles Darwin believed that evolution by natural selection occurs too slowly to observe in a human lifetime. But since then, many organisms have been caught in the act of evolving. Few, however, as dramatically as the Italian wall lizard. In 1971, 10 of these were introduced to the tiny Croatian island of Pod Mrcaru. Formerly insect eaters, the newcomers were forced to adopt a plant-based diet in their new home. According to biologist Duncan Irschick of the University of Massachusetts, Amherst, the lizards quickly evolved larger heads and stronger bites better suited to eating plants. But the most surprising adaptation occurred in the gut.

DUNCAN IRSCHICK (University of Massachusetts, Amherst):
They evolved structures in their stomach that enable these animals to break down and process the plant material that they’re now digesting. It would be the equivalent of humans evolving a new ear in several hundred years.

I’m Bob Hirshon for AAAS, the science society.