The Biology of Skin Color
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.
Our human ancestors in Africa likely had dark skin, which is produced by an abundance of the pigment eumelanin in skin cells. (See the related animation.) In the high ultraviolet (UV) environment of sub-Saharan (or equatorial) Africa, darker skin offers protection from the damaging effects of UV radiation. Dr. Jablonski explains that the variation in skin color that evolved since our human ancestors migrated out of Africa can be explained by the tradeoff between protection from UV and the need for some UV absorption for the production of vitamin D.
This film is appropriate for science classes from middle school to college. The content connects to key concepts in biology, human biogeography, genetics, and anatomy and physiology. Chemistry and biochemistry classes will appreciate the focus on the effects of UV radiation on DNA, folate degradation, and vitamin D synthesis.