Speed of Evolution

Lizards Rapidly Evolve After Introduction to Island
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.
In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com/news/2008/04/080421-lizard-evolution.html