Humans are the only primate that stays upright all of the time. Scientists think that this way because a) it was easier to hold things- this helped with foraging b) you still have two free limbs to hold stuff and c) walking upright is a more efficient means of travel. Because of going from “knuckle-walking” to “bipedal” humans’ear bones, feet, ribcage and pelvis were reshaped/restructured, the spinal cord was relocated and became more curved, the lower limbs were altered, and joint surfaces evolved to be larger. Humans have a lot less hair than other primates. This could be because a) it would make it easier to forage for food in the water b) it allowed early humans to lose heat faster on the savannahs c) there are less parasites. As human’s diet changed, we evolved to have stronger teeth and jaws, got a different skull and face shape, and an increased brain size. The larger brain led to language and communication skills, the ability to live in communities and work together. The brain size grew but the skull didn’t very much; the brain just folded to fit inside of the skull.