dezembro 15, 2007

Why Do We Walk?

Why Do We Walk?
by Patrick J. Kiger

Billions of people do it daily, but nevertheless, to scientists, human bipedalism has long been one of the great unexplained mysteries. Why do we walk on two legs? After all, other large primates, such as gorillas and chimpanzees, seem to be perfectly content relying upon the four-limbed style of locomotion known as knuckle-walking. Is bipedal walking really superior? How and why did we start getting around on just two limbs?

...a recently published study by University of Arizona weight to the notion that humans began walking upright because it was more efficient.

The researchers measured the oxygen usage of human walkers and compared it to knuckle-walking chimpanzees by putting both subjects on treadmills. People, as it turned out, burned up only a quarter of the energy expended by their closest genetic relatives...

Meanwhile, according to this Fox News story, another new study suggests that while early humans could walk on two legs, they were only about half as fast as modern humans, because they apparently lacked Achilles tendons.

Bill Sellers, a computational primatologist at the University of Manchester in England who led the research, believes that modern humans' well-developed Achilles tendon, which gives them a springy running stride, allowed the species to transition from a vegetarian diet to hunting for meat...

Science Channel

Sem comentários: