Donald Johanson is an American paleoanthropologist best known for discovering the fossil of a hominid known as Lucy in 1974. This significant find, which is about 3.2 million years old, provided crucial insights into human evolution and the development of bipedalism. Johanson has contributed extensively to the field of anthropology through his research and publications. He founded the Institute of Human Origins in 1981, which focuses on the study of human evolution. His work has helped to deepen our understanding of early human ancestors and their environments.