56 replies to this topic

[Still Waters]

Why hominids evolved upright walking is one of the biggest questions in human evolution. One school of thought suggests that bipedalism was the most energetically efficient way for our ancestors to travel as grasslands expanded and forests shrank across Africa some five million to seven million years ago. A new study in the Journal of Human Evolution challenges that claim, concluding that the efficiency of human walking and running is not so different from other mammals.

http://blogs.smithso...-human-walking/

[notoverrated]

always thought it was so they could see over the grass.

[Junior Chubb]

I would go for physical attraction myself, it might be a shot in the dark and an uneducated view but makes sense to me. Stand up slightly straighter, be the biggest, tallest and most dominant in your social group.

Oh, and its easier to carry your newly discovered tools...

[Subsonicjourno]

I thought it was so we could have our hands free...

Edited by Subsonicjourno, 20 September 2012 - 11:53 AM.

[IamLegend]

Free hands, better field of vision, and standing in tall waters are three off the top of my head.

[Abramelin]

Bipedal Wading in Hominoidae past and present.

by Algis Kuliukas B.Sc.(2001)


Abstract

The factors that contributed to the origin of human bipedalism are still not understood. Many have been proposed but the idea that the earliest bipeds waded in water-side niches seems to have been overlooked. This thesis investigates the plausibility of a “wading-origins” model for bipedality by making a number of potentially controverting predictions and testing them.

It found that the wading model fulfils a number of theoretical requirements. For example in, avoiding drowning, it provides the strongest possible adaptive pressure for an upright posture.

Evidence from apes in the wild show that though preferring to keep dry, they do go into water when necessary and tend to do so bipedally. An empirical study of captive bonobos found them to exhibit 2% or less bipedality on the ground or in trees but over  90% in water.

Human subjects showed wading to be faster than swimming at depths below hip height and that speed correlated closely with submerged body profile. Apes specialised for this niche would therefore be expected to minimise this profile. A sideways wading mode was found to generate less drag in humans than frontal wading, suggesting that if our sideways propulsion were stronger it would be the optimal method. A review of AL 288-1 skeletal morphology indicates a strong ability to abduct and adduct the femur. These traits, together with a very platypelloid pelvis, are consistent with those expected in an ape that adopted a specialist sideways wading mode. It is argued that this explanation of A. afarensis morphology is more parsimonious than others which have plainly failed to produce a consensus. The paleo-habitats of the earliest bipeds, as with all the evidence reviewed here, are consistent with the hypothesis that wading contributed to the adaptive pressure towards bipedality.

http://www.riverapes...alismThesis.htm

[Junior Chubb]

Subsonicjourno, on 20 September 2012 - 11:53 AM, said:

I thought it was so we could have our hands free...

They had cars and mobile phones back then?  

[synchronomy]

Still Waters, on 19 September 2012 - 08:11 PM, said:

Why hominids evolved upright walking is one of the biggest questions in human evolution. One school of thought suggests that bipedalism was the most energetically efficient way for our ancestors to travel as grasslands expanded and forests shrank across Africa some five million to seven million years ago. A new study in the Journal of Human Evolution challenges that claim, concluding that the efficiency of human walking and running is not so different from other mammals.

http://blogs.smithso...-human-walking/

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.

[Darkwind]

My thought is so you can see over the grass,it free the mouth for communication and free the hands for beating your opponent with a club. It takes a big club to beat a big cat off a kill, you wouldn't want to drop it and leave it behind when you fall back and regroup. I think big cats played a big roll in our evolution.

[Arbitran]

Well, for one thing, it allows the hands to be used for alternative tasks, like carrying food, and so on. It also allows one to see better over tall grasses like those in Africa, as well as to properly balance the enlarged cranium; standing erect is the most efficient way to tackle the pesky problem of large cranial capacity (at least in our case).

[Troublehalf]

Humans are not designed to walk up right. It's damaging to the back especially. However, the main reason we did it was because it allowed to carry more food.

If you have your hands free, you can pick food up and hold it against your chest, if you need to walk on four legs, or two with your forearms as support, you cannot carry stuff. Now we have cars and all that jazz, so it is in fact slightly negative... But we use our hands for so much now, that it's still an overall positive 'mutation'. Not to mention other things such as fighting and so on.

[Bling]

Troublehalf, on 20 September 2012 - 07:45 PM, said:

Humans are not designed to walk up right. It's damaging to the back especially. However, the main reason we did it was because it allowed to carry more food.

If you have your hands free, you can pick food up and hold it against your chest, if you need to walk on four legs, or two with your forearms as support, you cannot carry stuff. Now we have cars and all that jazz, so it is in fact slightly negative... But we use our hands for so much now, that it's still an overall positive 'mutation'. Not to mention other things such as fighting and so on.

That's why so many people develop back problems? I'm one of them.

[CRIPTIC CHAMELEON]

Darkwind, on 20 September 2012 - 02:27 PM, said:

My thought is so you can see over the grass,it free the mouth for communication and free the hands for beating your opponent with a club. It takes a big club to beat a big cat off a kill, you wouldn't want to drop it and leave it behind when you fall back and regroup. I think big cats played a big roll in our evolution.

Yes my thoughts as well but now I'm scared the meerkats will evolve and take over the world.  

[synchronomy]

Troublehalf, on 20 September 2012 - 07:45 PM, said:

Humans are not designed to walk up right. It's damaging to the back especially.

Where the heck did you hear that?
Humans have multiple, major musculoskeletal differences from great apes who walk on all fours.  We are specifically designed to walk upright.
If we were not designed to walk upright...why don't you try crawling around on all fours for a day.  Bet your knees couldn't make it until mid-day.

[synchronomy]

Bling, on 20 September 2012 - 07:48 PM, said:

If you have your hands free, you can pick food up and hold it against your chest, if you need to walk on four legs, or two with your forearms as support, you cannot carry stuff.

That's not true either.  Great apes can walk while carrying a baby or food.  They can walk quite easily with three limbs free.
They can even scratch their butt while eating a banana.