Origin Of Bipedalism Closely Tied To Environmental Changes

Space Daily ^ | 05-01-2002 | staff writer at Space Daily

[StructuredChaos]

A. is correct for the reasons cited plus reasons related to the ability to vary rates of breathing without direct reference to stride.

However, enter the following creature in the race. A human being in all respects but one. It runs on all four.

Now who is your winner? The 4man is.

Now take your 4man and enter him into the 100 against some nasty preadators. The nasty preadators win.

Now take 4man and while chasing his pray confront him with a quick predator. Chomp he is dead.

Now take 2man and while chasing his pray confront him with a quick predator. Thrust stab the predator is kept at bay.

The compromise from four to two legs under the savanah model only makes sense if your 2man is already a tool/weapon weilder. Alternativley it makes sense in the aquatic model even if tool making/weapon weilding has yet to appear.

This line of logic, if valid, has an interesting implication. It would appear that the question of which came first, bipetalism or weapon weilding/tool making, is crucial.

Answers?

[Diamond]

BTW, did you know your dog makes his own Vitamin C, and yet you cannot? Why would God create humans to be inferior to dogs? The answer has to do with "use it or lose it" and is a powerful indicator that early hominids ate fruit so exclusively that the need to make C was selected out and didn't come back. Else, God is a lousy craftsman.

That's the same sort of negative theological argument that Darwin used, with great effect. The only problem is, saying, God wouldn't have done it that way" is not a scientific argument. It is a simply a metaphysical argument based on certain notions of what God would or wouldn't do. Apparently evolutionists are the only ones who are supposedly allowed to invoke supernatural explanations and remain naturalists at the same time.

Cordially,

[norton]

"some apes maintained a forest-oriented adaptation, while others may have begun to exploit forest margins and grassy woodlands,"

Thanks, now I know why the desert is loaded up with two legged coyotes.

(You can take it as a pun, or as sarcasm; I don't get many twofers)

[gcruse]

His handiwork speaks for itself, ie, it's flawed.
There's nothing particulary intelligent about Intelligent Design. Evolution explains what theology would have us swallow unexamined.

Enlightenedly,

[mamelukesabre]

Why do you believe a 4man would win my race? As I see it, part of the efficiency of bipedal locomotion is the vertical alignment of the skeleton. In a structure composed of muscle and bone, the bone resists compressive forces, and the muscle resists tensile forces. A vertically aligned skeleton is mostly compressive...it's basically a pole balanced vertically. Very little muscle action is required to maintain that posture. Since bone resists compressive forces without any expenditure of calories, and muscle consumes much calories to resist tensile forces, vertical is superior.

By my reasoning, the worst structure would be something like an alligator. The feet are a long way from each other and the limbs are short. An alligator is not well suited to land travel. An improvement over an alligator would be something with long legs that have feet placed close together. Like a pig or goat or deer maybe. Now, a further improvement would be to somehow add springs to the feet...make the creature walk on its toes like a dog for instance. A further yet improvement would be to make the limbs very straight and make the creature walk with joints mostly in a straight position and also to stand with joints locked. Humans have this in their hind limbs. I'm not sure what 4 legged animals have this feature but I think elephants and camels and llamas do to some degree but not quite as strait and locked as humans.

Most 4 legged creatures have the joint that is equivalent to a human knee, that is the joint between the hip and ankle of the hind limb, in a very bent position. I think this is to facilitate a rapid acceleration but I'm not sure. But this definitely reduces efficiency while walking and standing.

Your first line in your post was about breathing rates and stride. I've never heard of this before. Are you saying that a four legged animal must breath in and out at specific times in its stride? I suppose this makes sense since the abdominal muscles are used more in 4legged locomotion.

The importance of efficiency though is not so much to win the race that I described. It's importance is that it allows a tribe or pack to support a much larger population on a givin allotment of food and to harvest food from a larger range. A pack of dogs beats a lepard. A tribe of humans beats a pack of dogs. Even if the individual dogs and humans are equal in size and weight and the human's only weapons are clubs, the humans still win. It takes more calories to support 100lb of dog than 100lb of human, giving equivalent activity level. Therefore the humans will generally outnumber the dogs in a confrontation and this more than makes up for the human's lack of biting and sprinting abilities. If you factor in the humans longer lifespan and larger brain, the human's ability to aquire more skills and experience in that longer life, and ability to communicate more effectively with hunting companions, the dogs have no chance. The dogs were destined to become either extinct or slaves to the humans.

[StructuredChaos]

I appreciate the thorough analysis. In your second paragraph, you have aptly described the 4man I was too lazy to detail. I was glossing over the description because the 4man was being used by me for illustrative purposes. Because the point I was attempting to make was that tool use had to proceed bipedal locomotion in a savanna type environ as opposed to an aquatic environ.

For our purposes consider our 4man a camel from the waste down. It was my belief, though I do not know it to be fact, that in an endurance contest a camel easily out performs a human. I would attach approximately 90 plus percent confidence to the accuracy of this belief. As indirect evidence of this fact I would refer to the ability of camels to travel great distances on little water. This would seem to correlate directly to the efficiency of their locomotion as rates of water use likely correlate highly with energy use.

I agree completely with your analysis of the physics and physiology of locomotion. Funny thing, is that the other day I learned that penguins, of all creatures, perhaps move with the greatest of efficient. They pivot/turn (waddle) themselves across terrain. In any event, I'm curious now about 2man v. camel. Again I think camel.

I know, the camel 4man comparison is not well made or necessarily a good fit here, but my ultimate point is. And I'll make the point, oddly, in a way which I find ironic. You don't find camels residing in savanna type environs. But put them on two camel legs and make them tool users and you have sandman :) a perfect fit for the savanna, actually, make them meat eaters also, or do they eat meat too - doubt it. I wonder how genetically related we are to the camel, lol. I have now officially advanced a new and novel theory henceforth to be referred to as the Sandman Theory.

My first inquiry: Wandering Bedouin. Why wandering? Certainly they are going somewhere. Or, do they in fact wander this being some vestigal instinct to migrate like camel?

[Diana in Wisconsin]

I don't know a thing about Evolution. I just want my flying car, d@mmit! Bipedal Hominids should have easily invented those by now! :)

[mamelukesabre]

I'm sure a camel would outperform a human if the race were to occur in the camel's neighborhood. But I stated that the race would occur in ideal conditions.

Camels chew their cud like a cow or sheep. Therefore it is highly unlikely that they can "stomach" meat. A big reason for a camels endurance is the hump, which is merely fat reserves. Humans have fat reserves all over their body.

Most efficient does not necessarily mean greatest endurance. If it did, a mouse would win since it burns fewest calories per mile walked. There are two more requirements besides efficiency. Energy reserves, and muscle. I would be very surprised if a penguin's leg muscles were up to the task of carrying a penguin as far a a man's legs could. Especially since penguins are primarily designed for swimming. Of course, in a penguins neighborhood, the human's performance would suffer drastically.

I believe that hopping creatures have the most efficient locomotion. Kangaroos and such. But this is just a variation of bipedal locomotion in my opinion. I don't have any references on this. But I seem to remember a study done with treadmills where the oxygen use was measured per mile hopped.

So, your 4 man creature has 6 limbs then? 4legs and two arms?

[Diamond]

His handiwork speaks for itself, ie, it's flawed.

You seem to have missed the point that your argument is not a scientific argument; it is a metaphysical argument predicated entirely upon certain assumptions, which may or may not be true, about what God might or might not do.

There's nothing necessarily wrong with making a theological argument, but it is still not a scientific argument. Even worse, what does "flawed" mean in the first place from an evolutionary standpoint? An accusation like that implies a standard. Unless your yardstick is independent of the thing measured there can be no measurement. How does evolution yield a measuring stick? What is it, and where do you get it from? How in the world can evolution produce anything "flawed"? What are you comparing the universe to when you say something is flawed?

There's nothing particulary intelligent about Intelligent Design.

Again, you have to assume intelligence in the first place to make such a judgment, even though your mind is, on your view, a product of the the non-rational. You have to also assume that intelligence and logic are valid in a non-rational universe, even though you cannot account for it.

Your theological argument is like a pot saying to the potter, "why did you make me like this?".

Cordially,

[gcruse]

I don't think the Vitamin C argument is theological, but its conclusion lessens the appeal of the notion of a perfect creator, making it somewhat theological, I suppose.

[StructuredChaos]

lol, how in the world did our discussion degenerate to hopping and waddling creatures. :)

This forum rocks.

Have a good one mamelukesabre and see you on another board sometime.

[livius]

Well, necessity is the mother of invention. God created us and created the universe, and God knows how it will all end, but our part in it is not static and in fact God put us in charge of the Garden.

When people freak out about global warming and other approaching crises, I always shrug and see them, real or not, as yet another stimulus to human invention.

[SunkenCiv]

Ancient Humans Walked But ‘Struggled To Run’
The Telegraph (UK) | 9-11-2007 | Roger Highfield and Nic Fleming
Posted on 09/11/2007 10:51:26 AM EDT by blam
http://www.freerepublic.com/focus/f-news/1894625/posts

[SunkenCiv]

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
http://www.freerepublic.com/focus/f-chat/1579810/posts

Early Humans Walked Peculiarly
Discovery News | 2-28-2006 | Jennifer Viegas
Posted on 02/28/2006 2:27:44 PM EST by blam
http://www.freerepublic.com/focus/f-news/1587166/posts

Ape To Human: Walking Upright May Have Protected Heavy Human Babies
Science Daily | 12-17-2007 | Springer.
Posted on 12/17/2007 4:50:35 PM EST by blam
http://www.freerepublic.com/focus/news/1940836/posts

[SunkenCiv]

Upright Walking Began 6 Million Years Ago
Newswise | Stony Brook University Medical Center
Posted on 03/20/2008 5:54:39 PM EDT by blam
http://www.freerepublic.com/focus/news/1989044/posts

[SunkenCiv]

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[KosmicKitty]

I just read another thread that it was because of the weight of human babies that had to be carried

Will someone make up their mind, please!