Why hominids evolved upright walking

[IamLegend]

Two legs might be just as efficient energy wise to four legs...but 2 legs are far slower than four so the evolution couldn't have been to outrun danger. Most mammals as small as rabbits and cats can outrun a human easily.

I just found this.

This is one of the last tribes on earth to hunt like this.

[sam12six]

and a horse can outrun an ostrich. So can a lion.

If it's the proportion and length of the legs that count why can a cheetah run faster?

All of the great apes running on 4 legs average 25-30 mph.

The fastest humans can barely touch 23mph...and that's Olympic level sprinters.

As I understand it (And I'm not claiming super specific knowledge. Everything I'm saying is based on a documentary about the relationship between the way an animal's legs are made and how fast it can run), leg proportion multiplied by some factor for leg length = speed. That speed is relative to the actual size of the animal.

A rabbit has super long calves and short thighs. Scaled up, they would be much faster than cheetahs. Of course, they might not if there were actually rabbits that big because body weight would adjust their relative speed down.

A great ape's legs are proportioned similarly to ours, but they are far stronger than we are per body weight. It's like a car having an engine that produces a given amount of horsepower and a motorcycle with tires half the diameter but a stronger engine. In the case of us and big apes, it's pretty much a wash (though lazy Orangs pretty much don't run ever).

Anyway, the animal's relative theoretical speed can change up or down based on proportional body weight (fat guy runs slower than fit guy with the same leg length and proportion), gait (cats' flexible spines allow them to take a bigger stride than most other animals, so they get a speed boost), and the aforementioned muscular strength per body weight - all of which is about speed and so it's sort of off topic as the OP was about efficiency.

Addressing the OP seriously, there could have been a single factor, but I doubt it. The article linked in the OP says basically that we're not supernatural. Our walking efficiency is within the norm for mammals our size - duh, we are mammals our size. Like apes, our legs aren't proportioned for sprints, they're proportioned for efficient long distance travel and probably has very little to do with our being upright. More likely, factors like being able to reach higher, see farther, etc were the environmental advantages that made evolution in that direction happen.

[Him over there]

Has no one considered that walking upright frees the front pair of hands to hold an item, pick something up, examine by holding close and turning and I am sure too many other things to list here, none of which would be easy if we walked on all fours which would cause the front hands to be thick skinned and indelicate.

[Bling]

Sorry...I goofed there!

No probs

[Abramelin]

We evolved because it's easier when you're walking upright to see BOOBIES!

And she would see your 'reaction' much easier too.

[salnal]

I think it has something to do with the ancient humans having a huge fascination with the stars and spent a lot of time staring and learning, standing upright would have been a lot easier to view the sky, just a personal theory that makes sense to me.

I think it has something to do with the ancient humans having a huge fascination with the stars and spent a lot of time staring and learning, standing upright would have been a lot easier to view the sky, just a personal theory that makes sense to me.

[Abramelin]

I thought the theory was we evolved bipedality to see over the grass. Another theory, though, is Maxine Sheets-Johnstone's sexual selection hypothesis.

I have a somewhat different theory.

Apes and monkeys (like many humans,btw) love to spy on a couple 'making love'.

But when walking on all fours between tall grass they'd have to come very close at the risk of being chased off, and by that spoiling all the fun.

So standing upright did have an advantage. Another one was the 'free hands', heh.

[The Mule]

I have a somewhat different theory.

Apes and monkeys (like many humans,btw) love to spy on a couple 'making love'.

But when walking on all fours between tall grass they'd have to come very close at the risk of being chased off, and by that spoiling all the fun.

So standing upright did have an advantage. Another one was the 'free hands', heh.

Reminds me of the guy in one of my anthro classes who did his paper that the developement of agriculture was spurred by mans quest for better beer

[Abramelin]

Reminds me of the guy in one of my anthro classes who did his paper that the developement of agriculture was spurred by mans quest for better beer

Lumping it all together you get something like this as the causes for our evolution from ape-like ancestors::

Walking upright (voyeurism in tall grass);

Agriculture (having a beer before the 'act' or while watching it);

Fire (having a smoke afterwards).

[Abramelin]

However, if it was bipedal, the couple could see the monkey thing! Not a particularly good adaptation.

I dunno, but I tend to be quite focussed when in the act...

However, I think I would notice someone sitting next to me, but not someone spying on me from 150 feet distance when I am busy with my girlfriend.

[The Mule]

Lumping it all together you get something like this as the causes for our evolution from ape-like ancestors::

Walking upright (voyeurism in tall grass);

Agriculture (having a beer before the 'act' or while watching it);

Fire (having a smoke afterwards).

Don't leave out tool use, crafting restraints for those who like a little kink....

[Abramelin]

Ahh...

Would you?

I am willing to give an example of what I experienced....

How shall I post this without being banned for eternity?

OK, here it comes.

There was this neighbour and she and I had just met. She had thanked me for helping her out once (she couldn't get inside her house, keys inside her house on a table, but I was able to open her door anyway, heh).

She gave me a copy of a CD, "Anastasia's" first album, as a present.

So we talked and talked and... talked,,,...and....then she really said she was glad she had found an excuse to finally meet me and have a private chat with me (the time I was able to open her door, she was with her mother).

OK, so the wrestling started. Clothes everywhere, well, you know, like the end of the earth is at hand and you still have something urgent to do...

Then there was this open window, she grabbed to lower edge of the windowframe, letting her long black hair dangling outside the window, waving to and fro at the rhythm of my ...uhm.. probing and taking samples for further research (or something, whatever).

Next morning I met an old neighbour of mine who lived opposite my house, in a 3 story building, and asked me, "Hey neighbour, that neighbour of yours, you are really pleased by her, eh??"

And he had a big fat smile from ear to ear.

At first I wondered why he said that... but then I knew.

Hmmmm...

I had not seen him watch us because we were too busy with our research.

And another day I met him again, and this is what he said: "You know that I am Italian. When I saw what I saw I was kind of happy, but not because I am some peeping-tom. We Italians like this spectacle, it makes us forget about all the sh1t going on in the world, and that some things will - glad to say - never change. But there were like 4 other neighbours complaining about what they saw the two of you do. Damn pricks."

.

Edited September 23, 2012 by Abramelin

[Abramelin]

The album I talked about is from the American (Jewish??) "Anastasia", a blond, white woman, often wearing shades, and singing with an African woman's voice.

I loved it, and nothing like the present Russian AnastaCias with their shrill high pitched voices that make my eardrums crack.

It was from the early 2000's.

.

Edited September 23, 2012 by Abramelin

[CRIPTIC CHAMELEON]

I remember seeing an article on back pain years ago that suggested if we scampered about on all fours (as apes do) then a lot of the back pain people suffer would not have developed. Its an interesting point of view and I have considered it true since hearing it. I also wonder what role our furniture plays in back pain too, again forcing us into positions we may not be ready for. I often sit on the floor, especially to eat, at work and at home, so far so good (I haven't opted for the scampering around on all fours yet though).

Hmm so you have been contemplating running around on all fours hey so was this a childhood dream or fantasy hmm.

[Abramelin]

The album I talked about is from the American (Jewish??) "Anastasia", a blond, white woman, often wearing shades, and singing with an African woman's voice.

I loved it, and nothing like the present Russian AnastaCias with their shrill high pitched voices that make my eardrums crack.

It was from the early 2000's.

.

I have searched and searched, and then finally found out I had spelled her name wrong ... it's "AnastaCia", with a -C-...

The CD I have thrown out the window (the same window), many years ago.

Anyway, for the record, this is her:

Edited September 24, 2012 by Abramelin

[Junior Chubb]

Hmm so you have been contemplating running around on all fours hey so was this a childhood dream or fantasy hmm.

I have contemplated it, but social pressure forces me to conform...

[Hawken]

I discovered a wild theory about humankinds past.

http://youtu.be/DwCaZaSon9A

[gOOgLer]

Humans evolved to bipedalism because the food was on trees. Just simple as that.

[pallidin]

Humans evolved to bipedalism because the food was on trees. Just simple as that.

Nah. Many non-bipedal animals are able to eat food from trees.

Evolution did it so that we could look better in suits, dresses and movies.

[Melo -]

idk but i like the sex i make with them

[synchronomy]

Humans evolved to bipedalism because the food was on trees. Just simple as that.

Then why did they ever leave the trees?

[Abramelin]

Then why did they ever leave the trees?

To pick up the fruit that had dropped from the trees?

[Render]

There are at least twelve distinct hypotheses as to how and why bipedalism evolved in humans, and also some debate as to when. Bipedalism evolved well before the large human brain or the development of stone tools.^[25] Bipedal specializations are found in Australopithecus fossils from 4.2-3.9 million years ago.^[26] Recent evidence regarding modern human sexual dimorphism (physical differences between men and women) in the lumbar spine has been seen in pre-modern primates such as Australopithecus africanus. This dimorphism has been seen as an evolutionary adaptation of females to bear lumbar load better during pregnancy, an adaptation that non-bipedal primates would not need to make.^[27][28] The different hypotheses are not necessarily mutually exclusive and a number of selective forces may have acted together to lead to human bipedalism. It is important to distinguish between adaptations for bipedalism and adaptations for running, which came later still.

Possible reasons for the evolution of human bipedalism include freeing the hands for tool use and carrying, sexual dimorphism in food gathering, changes in climate and habitat (from jungle to savanna) that favored a more elevated eye-position, and to reduce the amount of skin exposed to the tropical sun.

http://en.wikipedia.org/wiki/Bipedalism#Evolution

[regeneratia]

So they could pick the apple from the tree of knowledge and gain access to the plemora without the demiurge, who was unable to access the plemora himself?

Edited October 15, 2012 by regeneratia

[Junior Chubb]

To pick up the fruit that had dropped from the trees?

Never eat a windfall apple...

Edited October 16, 2012 by Junior Chubb