UNIVERSITY PARK, Pa. -- As people move more often and become more urbanized, skin color -- an adaptation that took hundreds of thousands of years to develop in humans -- may lose some of its evolutionary advantage, according to a Penn State anthropologist.
About 2 million years ago, permanent dark skin color imparted by the pigment -- melanin -- began to evolve in humans to regulate the body's reaction to ultraviolet rays from the sun, said Nina Jablonski, Distinguished Professor of Anthropology.