The wings of cliff swallows in Nebraska are getting shorter while turtles in Chesapeake Bay are getting larger. On the Galapagos Islands, different species are collapsing back into one. What has happened to evolution? The answer is very simple: us. Humans have transformed the planet beyond recognition – turning grasslands and forests into fields and cities and polluting air and water. And all of these changes have altered the course of evolution, often in surprising ways.