It's just easier to walk upright
Why did humans evolve to walk upright? Perhaps because it's just plain easier.
Bipedalism -- walking on two feet -- is one of the defining characteristics of being human, and scientists have debated for years how it came about.
So, in the latest attempt to find an explanation, researchers trained five chimpanzees to walk on a treadmill while wearing masks that allowed measurement of their oxygen consumption. The chimps were measured while walking upright and while moving on their legs and knuckles.
It turns out that humans walking on two legs use only one-quarter of the energy that chimpanzees use while knuckle-walking on four limbs, according to results published in this week's online edition of Proceedings of the National Academy of Sciences.
However, there was variability among chimpanzees in how much energy they used.
"What we were surprised at was the variation," said David Raichlen, assistant professor of anthropology at the University of Arizona. "That was pretty exciting, because when you talk about how evolution works, variation is the bottom line, without variation there is no evolution."
Original Article
Bipedalism -- walking on two feet -- is one of the defining characteristics of being human, and scientists have debated for years how it came about.
So, in the latest attempt to find an explanation, researchers trained five chimpanzees to walk on a treadmill while wearing masks that allowed measurement of their oxygen consumption. The chimps were measured while walking upright and while moving on their legs and knuckles.
It turns out that humans walking on two legs use only one-quarter of the energy that chimpanzees use while knuckle-walking on four limbs, according to results published in this week's online edition of Proceedings of the National Academy of Sciences.
However, there was variability among chimpanzees in how much energy they used.
"What we were surprised at was the variation," said David Raichlen, assistant professor of anthropology at the University of Arizona. "That was pretty exciting, because when you talk about how evolution works, variation is the bottom line, without variation there is no evolution."
Original Article