Darwin comes to town

With human populations growing, we're having an increasing impact on global ecosystems, and nowhere do these impacts overlap as much as they do in cities. "Urban ecologists" study how our manmade environments are changing the evolution of the animals and plants around us. Schilthuizen takes us around the world for an up-close look at just how stunningly flexible and swift-moving natural selection can be. He shows how the wildlife sharing these spaces with us is not just surviving, but evolving ways of thriving.