STUDYING evolution is a lot like studying tigers. You know your subject is there by the traces it leaves, but you don’t often see it in the flesh. This year, though, evolutionary biologists were treated to not one but several glimpses of evolution in action right before their eyes.
Take the little lizard known as Anolis sagrei. When researchers introduced a larger, predatory lizard onto the tiny Caribbean islands where they live, A. sagrei immediately began to evolve longer legs for speedier escapes. But then the little lizards learned to flee into the branches of shrubs, where the…
