Penn State University anthropologist Dr. Nina Jablonski walks us through the evidence that the different shades of skin color among human populations arose as adaptations to the intensity of ultraviolet radiation in different parts of the world.
Paul Andersen details the evolutionary processes of speciation and extinction. Stickleback evolution in Lake Loberg is used as example of rapid speciation. Adaptive radiation is illustrated using the Hawaiian honeycreeper. A brief discussion of extinctions and mass extinctions is also included.