There are three major historical points of evolutionary transformation of the bodyplan marking the transition from our common ancestor with Apes, Chimpanzees, and Bonobos to the lineage leading to Humans.
- Approximately 4 million years ago marks the transition to bipedal locomotion.
- Approximately 2.4 million years ago(+/- 0.3 mya) marks the beginning of a period of cortical expansion and an eventual elimination of the sagital crest.
- Approximately 200,000 years ago marks the emergence of the modern vocal tract of humans.