General primate characterisitics

• hands and feet adapted for grasping • large brains • short jaws • flat face • forward looking eyes (close together on front of face) • complex social behaviour

• Brain size: modern humans have a brain size ~1300 cm 3 (3x size of modern chimpanzees)  Complex language • Jaw Shape: shortening of jaws, flatter faces, changes in teeth • Bipedal Posture: upright posture and walking on 2 legs • Reduced size difference between sexes: less of a difference in the size of male and female humans (males 1.2x bigger) • Key Changes in Family Structure: monogamy, long term pair bonding, human infant dependency  Enhanced learning  Behaviour complexity

The tree dwellers and the collision between india and asia  drier climate forests of Africa and Asia contracted  increased area of savanna 5-7 mya  humans and chimpanzees diverged from common ancestor

Key Human Traits and Selective Advantages  large brain - ability to learn and to communicate through complex language.  Bipedal motion - freeing the hands for carrying infants or making and using tools.  dexterous hands provided the ability to fashion tools.