Human culture appears to have really developed when early hominids began making stone tools to butcher animals for their meat (earliest evidence; 2. 5 - 2 million years ago). By about 200,000 years ago, the human brain had reached its modern size, yet culture continued to evolve and change down to the present. It opened up a new abundant food supply including; leaves, flowers, fruits, insects, birds(cid:495) eggs, and even nesting birds; gripped the branches tightly: natural selection favoured those who judged depth correctly and who. This adaptation resulted in an increase in brain size: the primate brain: the cerebral hemispheres (areas of conscious thought) completely cover the cerebellum in monkeys, apes, and humans, this coordinates the muscles and maintains body equilibrium. A downward shift is a more advantageous arrangement for upright posture. The clavicle acts as a strut, placing the arms at the side of the body permitting them to swing sideways and outward.