Considering we have never met a Homo habilis or an Australopithecus, how do we know about these early human species? Disciplines such as anthropology, archaeology, primatology, and history give us bits and pieces of evidence to help solve the puzzle of how humans have evolved over time. While we have learned a great deal about this topic in the last hundred years, there are still many unanswered questions and more evidence to be found!

© Alfredo Dagli Orti/The Art Archive/Corbis

Acheulean stone tools like these were made by Homo erectus and represent a revolution in toolmaking some 1.6 million years ago. Our ancestors made the multi-purpose tools (sometimes referred to as hand-axes) by flaking off part of the surface to get a better edge and used the pear-shaped tools for digging, cutting wood or other plant material and for cutting and skinning game.

Content in this section from Khan Academy - Ways of Knowing - Early Humans