Posted on 02/28/2006 11:27:44 AM PST by blam
Early Humans Walked Peculiarly?
By Jennifer Viegas
Discovery News
Evidence In The Bones
Feb. 27, 2006 — At least two species of early humans were knock-kneed and walked rather uniquely, according to a new study on seven anklebones that belonged to various early human ancestors from eastern and southern Africa.
The study, which will be published in the April issue of the American Journal of Physical Anthropology, suggests that although the early humans walked on two feet, they did not always do so with our relatively smooth stride.
"This is hard to explain, but easy to demonstrate," said Dan Gebo, who co-authored the paper with Gary Schwartz, an Arizona State University anthropologist.
Gebo told Discovery News that modern humans, and our more recent ancestors, possess a walking technique that first involves the heel hitting the ground. As the body moves over the foot, the person stands on one foot while the other foot is starting to swing forward. We then "toe off as we go through a normal stride."
Gebo, a Northern Illinois University anthropologist, then explained that muscular early humans, called robust australopithecines, who lived between 2 and 1.4 million years ago, had a different gait.
"The robust australopithecines have modified their upper ankle joint so that when the lower leg moves forward to stance phase, it must follow the track of the joint and this joint curves inward," he said. "It then must backtrack as the leg and foot push off at toe off."
Gebo added, "In short, the knee of robust australopithecines must move in and out during each stride. It would look like the knee is slightly bent, where ours is straight. The gait is less efficient, especially over long distance walkings or runnings."
The shape of the anklebones suggests that at least two early human species, Australopithecus robustus and Australopithecus boisei, walked in this unique manner. Both looked very apelike and furry.
While the researchers think such early human relatives "had some gait peculiarities," they believe the ability to walk on two feet (bipedality) evolved only once because it requires so many anatomical changes in the pelvis, knees, lower legs and feet.
"We find it difficult to believe that all of these changes could occur more than once," Gebo said.
The scientists think bipedality must have occurred very quickly in human evolution, particularly since there was no three-limbed transitional phase.
During the period of evolution, our ancestors lost their grasping big toe muscles. This "toe" in African apes, such as chimpanzees, helps in climbing trees. Gebo said we also developed platform-like, weight-bearing bodies, short toes, stocky foot bones and joints that can lock up so we do not need muscle power to remain erect.
Bruce Latimer, executive director of The Cleveland Museum of Natural History, told Discovery News that he agrees bipedality evolved no more than once within the human lineage, but he does not believe "that any non-pathological hominid ever walked with tibiae that inclined medially (knock-kneed)."
Latimer added, "Moreover, it is quite impossible to reconstruct such behavior from isolated bones. The authors have taken on the ambitious task of trying to make sense out of isolated anklebones. They have done a nice job but have, perhaps, pushed the functional analysis a little too far."
Gebo and Schwartz, however, plan to continue with their research to determine if their theorized knock-kneed gait might have conferred some unknown advantages.
Schwartz told Discovery News, "Paleoanthropologists have long been fascinated with the robust australopith phase of human evolution as they are one of the most highly specialized and derived group of fossil humans.
They have massive teeth, large, heavily constructed jawbones, and enormous chewing muscles, but they have always been thought of as fairly ‘standard-brand’ (for a hominin) from the neck down."
Schwartz added, "We know now, based on our work, that they were as interesting from the knee down as they are from the neck up."
You know, now that I think about it, Hillary's ankles look pretty australopithecine. And very robustus.
My Gran Pap was no dug gun asian !!!
He were a six toed slack jawed red neck booger eatin dumb ass inbreed jus like me!!!
heh
Aw, heck, so do I when I first get out of bed in the morning. That stagger from bed to shower is probably somewhat amusing. Especially on the mornings when I really don't want to get up and I walk into the wall.
I've got bad news. Look at the post above yours :)
"... the American Journal of Physical Anthropology, suggests that although the early humans walked on two feet ..."
As opposed to what, three? Five?
I wonder if it was because they wore lightweight loafers?
All the evolution I want to know about can be found in The Big Book, thank you very much.
Later Humans Spelled Peculiarly
:-)
I find it difficult to believe that they could occur at all.
Two feet and ten knuckles? :)
Or would that be eight knuckles?
Gimmee about four beers, then tell me to walk out to the next bar up the street.
Peeeee - Que - Leee - R to be sure!
Four. Like, you know, other apes.
"eep eep oop oop eep eep"
woo hoo woo hoo woo hoo
Ugga booga!
A million years from now, the only known fossil of Homo Sapiens will stun the scientists.
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