Human Evolution
- Posted by e2 on 08.02.08
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Judging from the fossil record, apes ancestral to humans, gorillas, and chimpanzees roamed widely in Asia, Europe, and Africa some 12 to 28 million years ago. Toward the end of that period (the Miocene) one appears in North India and East Africa, Ramapithecus, who may be ancestral both to later hominids and to modern humans. His species were small like gibbons, walked upright on two feet, had human rather than ape cornerteeth, and therefore probably used hands rather than teeth to tear their food. From that time evolution toward humanness must have proceeded through various phases until the emergence of modern homo sapiens, about 70,000 years ago.
In the Miocene period before Ramapithecus appeared, there were several time spans in which, over large areas, the climate became dryer and subtropical forests dwindled or disappeared. A standard reconstruction of events is that groups of apes, probably in Africa, had to come down from the trees and adapt to terrestrial life. Through natural selection, probably over million of years, they developed specialized feet for walking. Thus freed, the hands came to be used not only (as among apes) for grasping and tearing, but for regular carrying of objects such as weapons (which had hitherto been sporadic) or of infants (which had hitherto clung to their mothers’ body hair.
The spread of indigestible grasses on the open savannahs may have encouraged, if it did not compel, the early ground dwellers to become active hunters rather than simply to forage for small, sick, or dead animals that came their way. Collective hunting and tool use involved group cooperation and helped foster the growth of language out of the call systems of apes. Language meant the use of symbols to refer to events not present. It allowed greatly increased foresight, memory, planning, and division of tasks – in short, the capacity for human thought.
With the change to hunting, group territories became much larger. Apes range only a few thousand feet daily; hunters, several miles. But because their infants were helpless, nursing women could hunt only small game close to home. This then produced the sexual division of labor on which the human family has since been founded. Women elaborated upon ape methods of child care and greatly expanded foraging, which in most areas remained the primary and most stable source of food. Men improved upon ape methods of fighting off other animals and of group protection in general. They adapted these methods to hunting, using weapons which for millennia remained the same for the chase as for human warfare.
Out of the sexual division of labor came, for the first time, home life as well as group cooperation. Female apes nest with and provide foraged food for their infants. But adult apes do not cooperate in food getting or nest building. They build new nests each night wherever they may happen to be. With the development of hunting-gathering complex, it became necessary to have a G.H.Q., or home. Men could bring meat to this place for several days’ supply. Women and children could meet men there after the days’ hunting and could bring their vegetable produce for general consumption. Men, women, and children could build joint shelters, butcher meat, and treat skins for clothing.
Later, fire came into use for protection against wild animals, for lighting, and eventually for cooking. The hearth then provided the focus and symbol of home. With the development of cookery, some humans – chiefly women and perhaps some children and old men – came to spend more time preparing nutrition so that all people need spend less time in chewing and tearing their food. Meals – already less frequent because of the change to a carnivorous diet – now became brief, periodic events instead of the long feeding sessions of apes.
