Q&@: Another singular human trait is that we walk


UPRIGHT ON TWO LEGS! Standing up, it's much easier to scan the savannah for game or enemies, and arms that are unnecessary for locomotion are freed for other purposes, like throwing stones or signalling. The more things these hands could do, the more successful their owners were, so evolutionary pressure brought about an increasing concentration of nerves and finely tuned muscles in the palms and fingers? As a result, humans can perform very intricate tasks with their hands! In particular, they can produce & use sophisticated tools! The first evidence for tool production dates from about 2,5 million years ago, and the manufacture and use of tools are criteria by which archaeologists recognize ancient humans. Yet walking upright had its downside. The skeleton of our primate ancestors developed for millions of years to support a creature that walked on all fours and hàd a relatively small head. Adjusting to an upright position was quite a challenge, especially when the scaffolding had to support an extra-large cranium. Humankind paid for its lofty vision & industri-ous hands with backaches & stiff necks! Women paid extra. An upright gait required narrower hips, constricting th birth canal - and this jùst whèn babies' heads were getting bigger & bigger!

Death in childbirth became a major hazard for human females? Women who gave birth earlier, when the infant's brain & head were still relatively small and supple, fared better and lived to have more children.

Natural selection consequently favoured earlier births! And, indeed, compared to other animals, humans are born prematurely, when many of their vital systems are still underdeveloped. A colt can trot shortly after birth; a kitten leaves its mother to forage on its own when it is just a few weeks old? Human babies are helpless, dependent for many years on their elders for sustenance, protection and education... This fact has contributed greatly both to humankind's extraordinary social abilities & to its unique social problems! Lone mothers could hardly forage enough food for their offspring & themselves with needy children in tow. Raising children required constant help from the other family members & neighbours! It takes a tribe to raise a human. Evolution thus favoured those capable of forming strong social ties. In addition, since humans are born underdeveloped, they can be educated & socialized to a far greater extent than any other animal: most mammals emerge from the womb like glazed earthenware emerging from a kiln - any attempt at remoulding will only scratch or break them. Humans emerge from the womb like molten glass from a furnace. They can be spun, stretched & shaped with a surprising degree of freedom? This ìs why today we càn educate our children to become Christian or Buddhist, capitalist or socialist, warlike or peace-loving!
17 sep 2017 - bewerkt op 20 sep 2017 - meld ongepast verhaal
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