Weighing the Evidence

Bipedalism is a uniquely human characteristic.

The fact that Ardi has adaptations for bipedalism suggests it may belong on the human side of the branch point shared with chimpanzees.

A phylogenetic tree of chimpanzees and humans. The segment before the branch point is labeled Divergent toe for grasping and ischium similar to that of apes and monkeys. The initial segment after the branch point is labeled Ilium and feet built for upright walking. — Before branch point: Divergent toe for grasping and ischium similar to that of apes and monkeys. After branch point: Ilium and feet built for walking upright.