Have you ever wondered why there were so many types of dinosaurs, ranging from the elaborately crested Styracosaurus to the huge-clawed Therizinosaurus to the tiny Microraptor? Well, an experiment conducted over the last 35 years by a team of Belgian researchers has shown that evolution (especially in lizards) can work more quickly than you'd think.
In 1971, the scientists transplanted five pairs of Italian wall lizards into a completely new environment, moving them from one island in the Adriatic Sea to another. Returning to the island in 2006, they found distinctive changes in the population of lizards descended from these lucky founders--including altered head shapes and new structures in the intestine to help digest tough plants. (On their home island, the omnivorous lizards had subsisted mainly on bugs.)
Of course, it's tricky to extrapolate an experiment on modern lizards 100 million years into the past. But there's no reason to believe evolution worked differently in Jurassic times than it does today, which may well help to explain the broad diversity of the dinosaurs.
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