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Humans began walking upright to carry scarce resources, chimp study suggests

ScienceDaily (Mar. 23, 2012) -- Most of us walk and carry items in our hands every day. These are seemingly simple activities that the majority of us don't question. But an international team of researchers, including Brian Richmond at the George Washington University, have discovered that human bipedalism, or walking upright, may have originated millions of years ago as an adaptation to carrying scarce, high-quality resources. This latest research was published in this month's Current Biology.

The team of researchers from the U.S., England, Japan and Portugal investigated the behavior of modern-day chimpanzees as they competed for food resources, in an effort to understand what ecological settings would lead a large ape -- one that resembles the 6 million-year old ancestor we shared in common with living chimpanzees -- to walk on two legs.

"These chimpanzees provide a model of the ecological conditions under which our earliest ancestors might have begun walking on two legs," said Dr. Richmond, an author of the study and associate professor of anthropology at GW's Columbian College of Arts and Sciences. "Something as simple as carrying -- an activity we engage in every day -- may have, under the right conditions, led to upright walking and set our ancestors on a path apart from other apes that ultimately led to the origin of our kind."



The fact is that what we're experiencing right now is a top-down disaster. -Paul Krugman
by dvx (dvx.clt ät gmail dotcom) on Sun Mar 25th, 2012 at 01:19:56 PM EST
[ Parent ]
Paleo-anthropology runs around in cycles of 'bout 20 years and it's time for this to cycle back in.  Saying there is A reason for bipedalism is like saying there is A reason for ice cubes.  There's an ecological niche for bipedal species and humans happened to be descended from one of the hominid species that drifted (evolved) to fill it on the African savannah.  

Homo sap. sap. needs to stop thinking we're the bee's knees and cat's pajamas of the Entire Friggin' Universe.

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

by ATinNM on Mon Mar 26th, 2012 at 03:14:01 PM EST
[ Parent ]
is the thing about climate change slowly transforming the forest into savannah, so the apes had to move fast from one group of trees to the next, and it helps if you walk upright because you can see the predators over the tall grass. Or whatever.

It all adds up. Change the mode of locomotion, you free up your hands to carry things that you would have otherwise left behind. So you get to spend more time perfecting your tools. Feedback, rinse and repeat.

It's all good. The researchers probably didn't write the press release.

It is rightly acknowledged that people of faith have no monopoly of virtue - Queen Elizabeth II

by eurogreen on Tue Mar 27th, 2012 at 03:36:53 AM EST
[ Parent ]
But don't the predators hidden in the tall grass then get you? Wasn't there a long gap between walking upright and the invention of lawnmowers?
by gk (gk) on Tue Mar 27th, 2012 at 04:06:58 AM EST
[ Parent ]
The well known Lucy:

he discovery of this hominin was significant as the skeleton shows evidence of small skull capacity akin to that of apes and of bipedal upright walk akin to that of humans, providing further evidence supporting the view that bipedalism preceded increase in brain size in human evolution ...

And the lesser known Ardi:

A. ramidus feet are better suited for walking ...

Researchers infer from the form of Ardi's pelvis and limbs and the presence of her opposable big toe that she was a facultative biped: bipedal when moving on the ground, but quadrupedal when moving about in tree branches. Ardi had a more primitive walking ability than later hominids, and could not walk or run for long distances.

Goes to show bipedalism arose before the increase in brain size.  

Ardi is even more interesting due to:

The canine teeth of A. ramidus are smaller, and equal in size between males and females. This suggests reduced male-to-male conflict, pair-bonding, and increased parental investment. "Thus, fundamental reproductive and social behavioral changes probably occurred in hominids long before they had enlarged brains and began to use stone tools"

Implying modern human-like in-group socialization and conflict resolution, and the relatively well developed pre-frontal cortex required for such, arose first ... even before 100% bipedalism and tool use.  

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

by ATinNM on Tue Mar 27th, 2012 at 11:42:55 AM EST
[ Parent ]
Very interesting, the bit about canines...
Compared to the chimpanzee, and like humans, bonobos have relatively longer legs, shorter arms, and a narrower trunk. The skull sits upright on the spine, and they have smaller canine teeth. There is sexual dimorphism in the canines where the males' are longer than the canines of the female. ... The average body mass for an adult male bonobo is around 85 pounds, and for the female it is around 65 pounds.
But Bonobos also have "reduced male'to-male conflict", don't they?

There are three stories about the euro crisis: the Republican story, the German story, and the truth. -- Paul Krugman
by Migeru (migeru at eurotrib dot com) on Tue Mar 27th, 2012 at 11:54:27 AM EST
[ Parent ]

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