ANT 101 Lecture Notes - Lecture 24: Natural Selection, Foramen Magnum, Brain Size
Document Summary
Found close to the earliest stone tools. Still had a small brain (450 cm^3) First members of the genus homo 2,4 mya. At least 15 individuals found in this same cave. The shape of the face and skull are homo-like, but the brain remains small. Larger animals tend to have larger brains. Brain: body size ratio important for cross-species comparisons. Proportion of brain size relative to body size (usually weight) More recently evolved portion of the cortex (neo = new) More grooves and folds in the human brain. Rapid period of brain development before birth. Expensive for mother too the last 5% takes a greater amount of time to develop. 50% of all infant"s energetic output devoted to brain development. 20-25% of adult resting metabolic energy goes to brain maintenance. Foragers needed to be familiar with home ranges, how to get food, when it"s. Animals had to recognize each other, for networks, interact, ect.
