Despite a fragmentary fossil record, paleoanthropologists have assembled a solid general picture of human evolution. They have traced hominins–that is, species that are bipedal and that are more closely related to humans than to other apes–back more than six million years. In this clickable illustration, follow the trajectory of hominin development from the earliest known species right up to our own kind, Homo sapiens.

Note: The illustration, adapted with permission from the Smithsonian Intimate Guide to Human Origins by Carl Zimmer (Smithsonian Books, 2005, p. 41), does not include all hominin species that experts have proposed but rather offers a representative sample. Thanks to Daniel Lieberman, Professor of Biological Anthropology at Harvard University, for consultation on this feature.