1. Human females selected males who could find the necessities of life. They allowed sexual access to men who could solve problems - hunt for food, find shelter, find water.
2. They mated with these problem solvers, and had better problem-solving children. The women saved the good genes through their children.
3. The Homo species stood up. Walking upright can save up to 70% of the calories of a chimp who walks on all four limbs. This energy saving permitted:
4. Brains start to increase in size with Homo Habilis, about 2.3 millions years ago.
5. Modern man begins to make stone tools. A stone tool can break bones left behind by other predators, and humans can eat the bone marrow of a carcass, which is rich in calories, which also supports larger brains.
6. Hunting for meat helps feed the increasing need for calories. In modern man, the brain requires 25% of all calories consumed.
6. Modern man solves the hunting problem by becoming mid-day endurance hunters. Hunting at midday, when the heat was intense meant that predators of man were not interested in hunting. Think of the lion under the tree avoiding the mid-day sun. Modern man has a tremendous advantage over its four-legged prey. The cross section of sunlight man suffers is less than half that of an antelope, who's back takes all the heat. Man is standing upright, his back doesn't take all of that heat. If man can keep the antelope walking, it will overheat until the point where it can no longer move because sunstroke has drained all of his energy, and the hunter can insert his spear at his leisure. We are lucky to have a present day example of this style of hunt in video:
Bushman video of endurance hunting.
7. Man looses hair, which would heat them up unnecessarily given their niche they have found of hunting niche at mid-day. Apparently, man develops two kinds of lice. Lice on the head is different from lice near the genitals. The lice near the genitals is of the type found in gorillas. Perhaps they used a gorilla nest for sleeping? These two kinds of lice can tell us when the hair loss started via the genetic clock.
8. Man perspires, which helps to cool him off.
9. All mammals have a 6-layer neocortex, but human neurons have significantly fewer ion channels than other mammalian neurons. The lower density of ion channels may contribute to more efficient brain function in humans.
10. Neural plasticity allows for modern man to become expert by directing more neurons to a particular piece of knowledge.
11. Culture. Information passed from one generation to the next. Stone tool making, voice memory (rhyme), writing, papyrus, parchment, paper, printing - the internet.
