Physical anthropology is a biological science that deals with the adaptations, variability, and evolution of human beings and their living and fossil relatives. Because it studies human biology in the context of human culture and behavior, physical anthropology is also a social science. The AAPA is the world's leading professional organization for physical anthropologists. Formed by 83 charter members in 1930, the AAPA now has an international membership of over 2,200. The Association's annual meetings draw more than two thousand scientists and students from all over the world.