Early humans migrated widely through Eurasia. Why were they so restless and why did their great-ape ancestors remain in place? Leaving the Trees Fossil evidence suggests that human ancestors lived in mixed grassland and trees (savanna) by approximately four million years ago.
At this time, some hominins (i. e., humans and great apes) walked upright based upon the relatively complete remains of Lucy.
Lucy had the hips, and knee, anatomy associated with bipedalism. Lucy is essentially a missing link between apes and humans, having some undeniably modern traits and some distinctly simian ones like smaller brains and larger intestines.Read more on psychologytoday.com