Our family tree extends back for five to seven million years to the time when our ancestors took their first two-legged steps on the path toward becoming human. During this vast period of time, our family tree grew to include many ancestors representing different species from our evolutionary past. Some of these species were our direct ancestors. Others were on side branches on our family tree and like ancestral ‘cousins’.

সোর্স : http://humanorigins.si.edu/education/introduction-human-evolution