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."
Yup. From the article:
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."
Caveat Emptor indeed...
You would know...
It's easy Pat. They go to your profile page and click on the "in forum" tab. You're their chosen high profile target. Then they FR mail their own list with a link.
The First Man Was a Woman
I can't prove it, but I believe the first man was a woman.
Modern science has used mitochondrial DNA to track human origins back to a single female. This is the so-called Eve hypothesis.
I believe that this was the first fully human Homo Sapiens. A girl was born with a genetic 'defect' in her mitochondria. The mitochondria control the enzyme activity in the cell. This change affected her metabolism at a deep cellular level.
The first human had an altered metabolism that manifested itself in a suite of gross differences:
She lacked vibrissae, the sensory whiskers common to all other mammals.
She had full lips, not the thin line at the rim of the mouth typical of other species.
She was weak, compared to others of her kind.
Her features retained a more child-like appearance as she grew up.
But, the two most critical differences were a lack of body hair, and a monthly estrus cycle.
Why are the last two most critical?
The lack of body hair provided an interesting advantage. To understand this, let's look at cats. There is a breed of hairless cat. Instead of fur, they have a velvety skin. Their owners often comment on how affectionate their cats are. Affectionate? Not really, these cats are just COLD, they snuggle to keep warm!
Back to our first human, she sure is cuddly. She is much more desirable than her standoffish hairy sisters.
Rather than the annual fertility cycle, she is 'in heat' all of the time. Cuddly and friendly too!
Lacking muscle strength, she needed to be protected. The beginnings of love as we now understand it.
That she needed protection is deeply ingrained it the human psyche. In propaganda there are surprisingly few common themes. The enemy is depicted as snakes, spiders, octopus, and, ... and ... hairy ape-men seizing the furless women. The massive muscular King Kong is interested in the petite Fay Rae. Did you ever wonder why this resonated with the audience?
Simple. The first man was a woman...
To all: I have to own up to having read "The Naked Ape" in college about thirty years ago and have never since been able to take the anthropologists sifting through chimpanzee bones in the Olduvai Gorge seriously. I don't claim any ownership of the "aquatic origin" but it's the only one I've ever heard that actually made any sense. I sometimes yell at anthropolgy programs on Discovery and the Science Channel: "Hey, s***head, you're looking in the wrong place! Figure out where the beaches were 2 million years ago and call me back."
Well yes there is, but you prefer not to.
Verily, I am the most misunderstood of men.
Heck yeah! TODAY 80% of the human population lives within 100 miles of the coast.
During the last Ice Age sea level was 200 feet lower.
Do the math, guys...
And let's not forget, Aquatic theory also explains why sushi tastes so darn good!
Indeed. I first heard of the Aquatic Ape Hypothesis after college, on a paleoanthropology newsgroup.
I took several courses in human evolution in college, and not once had I heard of this theory. Aquatic theory is so much better than Savannah theory at explaining plainly observable human characteristics that I feel like it's the college courses themselves that are an evolutionary throwback to a more primitive era.
That is a legitimate function. :-)
:') another "Blam topic":
Early Human Ancestors Walked On The Wild Side
Eureka Alert - ASU | 2-16-2006 | Garu Schwartz - Skip Derra
Posted on 02/16/2006 1:14:54 PM EST by blam
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The aquatic theory doens't pass my smell test, but I would note that most agree that the earliest man was a beach comber of sorts --- ate lots of shellfish, fish, and other fairly-easy-to get protein.
Hoo-ah!
Look at your webbed fingers.
SOme more of the dumbest crap on earth.
I first heard that one from Red Skelton! Very funny!
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