AP Biology Videos

Hummingbird Species in the Transitional Zones

The hummingbirds that live on the east slope of the Andes Mountains in Ecuador have adapted to a range of habitats, from steamy lowland rainforest to windswept alpine meadows. Biologists Smith and Schneider, studying the differences between these adjacent populations, are finding that natural selection in different ecological niches has pushed the birds down different evolutionary paths and created new species, even though the populations have not been isolated from each other geographically.

Chimps & Baboons - Behavioral isolation

This segment from Evolution: "Why Sex?" compares chimpanzee and bonobo society. Although they are close relatives, chimps and bonobos have strikingly different social dynamics: chimps society is prone to violence, and bonobos are relatively peaceful. Why? One theory suggests that a small change in the availability of food may have encouraged the evolution of today's chimp and bonobo societies. Researchers Richard Wrangham and Amy Parish comment on the group dynamics of the two species.