EVERYDAY SCIENCE

Detailed explanation-1: -Key Points. All primates are descended from tree-dwellers, exhibiting adaptations which allow for tree climbing that include: a rotating shoulder joint, separated big toes and thumb for grasping, and stereoscopic vision.

Detailed explanation-2: -Many traits unique to the human lineage were long thought to have originated between 2.4 million and 1.8 million years ago in Africa. These include a large brain and body, long legs, reduced differences between the sexes, increased meat-eating, prolonged maturation periods, increased social cooperation and tool making.

Detailed explanation-3: -Large brains (in relation to body size) Vision more important than sense of smell. Hands adapted for grasping. Long life spans and slow growth. Few offspring, usually one at a time. Complex social groups.