Comment on Ardi and implications

[ArmorPierce]

So I realize that it was a while ago that the finding was released but I was sitting at the barber shop and it had a a magazine with an article about it.

So the article talked about the skeleton and how it was surprising in that it was an upright walker that didn't have the traits that you would expect from an animal that did knuckle-walking like chimpanzees and gorillas. I guess this means that chimps and gorillas each evolved knuckle walking independently. I would also assume that it means our last common ancestors looked less like chimpanzees, which is what a lot of people use as a comparison of what our early ancestor looked like and perhaps more like gibbons (my speculation).


http://www.youtube.com/watch?v=hlzRCHAS ... re=related

The article continued with experts speculating as to why humans evolved to be bipedal.

Considering how gibbons walk and move when not in the trees, does it not make the case for why we evolved to be bipedal a lot easier? Gibbons are a lot more adapted to life in the trees, as opposed to on the ground, than humans or chimpanzees. When on the ground the way that they walk looks fairly awkward being in between walking up-right and walking on all 4. Since humans never had a walking on all 4 phase, doesn't it make it a lot easier to hypothesize that humans evolving to be bipedal whereas chimps evolved to walk on all 4 was merely evolutionary fluke and merely two possible takes for becoming more adapted to life the ground as opposed to the trees? No longer do you have to explain why humans first evolved to walk on 4 and then later started standing up. Is anyone suggesting?

Let me know if I'm totally off base

[Johonebesus]

Orangutans can also walk upright comfortably. For some time it has been suggested that our upright posture is the result of a primeval arboreal lifestyle. Because both gorillas and chimpanzees walk on their knuckles, it was assumed that our ancestors became more arboreal after the split with chimps, then were forced back into a terrestrial lifestyle due to the drying out of West Africa.

Recently palaeontologists have found several apes from around the time of the man/chimp split or even earlier that appear to have been bipedal. Then there are the anatomical differences between gorillas and chimps. It turns out that the anatomy and mechanics of their wrists and hands are quite different, leading some to suggest that they evolved knuckle-walking independently. Between these two lines of evidence there is a case to be made that anthropoid apes were mostly bipedal almost as soon as they came down from the trees, so the living African apes are just as derived as humans.

[Aaron]

Just a tangent but around 35-45 where the ape stops bobbing and runs off while looking at the camera, it's eerily human like.

[Mayabird]

Yes, this is actually one of the current bigger hypotheses going around, so a lot of the pros think there's merit to it. The last National Geographic issue even had a little section that discussed it. The crux was that the arboreal apes can walk bipedally, but not very well or very long because their big toes are splayed out, though it does makes climbing easier. Make a lot of selection pressure by forcing them to the ground and needing to walk a lot, wait for a mutation, and there you have it.