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A new study, based on a famous set of fossilized footprints in Africa (pictured), shows that Australopithecus likely walked upright, like modern man.  (Source: John Reader/Photo Researchers)

However, Australopithecus's long body and stubby legs would make it ill-suited for a footrace with a human.  (Source: BBC)
Man's ancestors were standing and walking tall -- more so than previously realized

Evolutionary biologists and paleontologists admit there's a lot they don't know, but they've also made remarkable progress [1][2][3][4][5][6] in recent years.  From multiple hominid fossil discoveries [1][2][3] filling in mankind's "family tree", to direct observations of evolution, the field is seeing a veritable renaissance.

The fascinating discoveries continue with a study [abstract] published this month in the peer-reviewed journal Interface.  The work examines the footprints of Australopithecus afarensis, an early hominid and presumed ancestor of Homo sapiens.

It comes to the surprising conclusion that previous work -- which asserted that up to around 1.9 million years ago hominids likely walked in a crouched position, before undergoing a transition to upright posture -- was likely flawed.  

The new study found that the Laetoli footprints, found in the volcanic ash of the nearby Sadiman Volcano in Tanzania (east Africa) show arguably that hominids walked upright far longer ago than previously thought.

The study comments:
It was previously thought that Australopithecus afarensis walked in a crouched posture, and on the side of the foot, pushing off the ground with the middle part of the foot, as today's great apes do. We found, however, that the Laetoli prints represented a type of bipedal walking that was fully upright and driven by the front of the foot, particularly the big toe, much like humans today, and quite different to bipedal walking of chimpanzees and other apes.

Quite remarkably, we found that some healthy humans produce footprints that are more like those of other apes than the Laetoli prints. The foot function represented by the prints is therefore most likely to be similar to patterns seen in modern-humans. This is important because the development of the features of human foot function helped our ancestors to expand further out of Africa.
The new work was thoroughly vetted by a team of renowned Ph.D researchers from the University of Liverpool, University of Manchester, and University of Bournemouth.

The footprints were first discovered in 1976 by distinguished paleoanthropologist Mary Leakey.  They were dated to be 3.7 million years old, using the potassium-argon method (K/Ar), which allows the age of volcanic sediments to be estimated accurately to within a statistical window of a couple thousand years.

The remarkable discovery was made possible by the fortunate tendency of rain to turn loose volcanic ash to tuff, a rocky deposit.

The footprints were significant in that they showed no signs of handprints, which would indicate that Australopithecus walked with the assistance of its arms, like an ape.  Upright posture is seen as a distinguishing factor between hominids -- like humans, neanderthals, and Australopithecus -- versus apes and monkeys.

The new study suggests upright bipedalism could have evolved around the time that the earliest hominids descended from trees to roam the ground on two feet.  It comments:
Our work demonstrates that many of these features evolved nearly four million years ago in a species that most consider to be partially tree-dwelling. These findings show support for a previous study at Liverpool that showed upright bipedal walking originally evolved in a tree-living ancestor of living great apes and humans.
The study goes on to say that while bipedal, Australopithecus wouldn't be on a level playing field in a race with a modern human.  The team writes:
Australopithecus afarensis, however, was not modern in body proportions of the limbs and torso.

The characteristic long-legged, short body form of the modern human allows us to walk and run great distances, even when carrying heavy loads. Australopithecus afarensis had the reverse physical build, short legs and a long body, which makes it probable that it could only walk or run effectively over short distances.
While the location of the first primates (circa 35-40 million years ago) and the first humans (circa 500,000 years ago) are still the topic of active debate, most evidence points to the first hominids as having evolved in Africa, around 4-5 million years ago.

Now yet another piece of the puzzle has fallen into place.

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Nice to see paleoanthropology on Da*$#Tech!
By Gigantopithecus on 7/21/2011 9:06:27 AM , Rating: 2
To address a criticism posted of this piece, Crompton and colleagues are not 'covering old ground' as it were. Though the Laetoli footprints have been analyzed and studied by numerous researchers in the past, some have argued that their makers did not walk like humans, while others have. Crompton et al. used a novel and 'high-tech' method in their analysis and confirmed what other researchers, including me, have concluded about australopithecine bipedalism.

This is how science works. Many experts look at evidence in different ways. The more eyes looking at more angles that see the same thing, the more we're confident that we're right. From computer science to cavemen, science just plain works, unlike superstitious pseudoscience (e.g. intelligent design).

Thanks for covering this on DT, Jason!

By Gigantopithecus on 7/21/2011 9:07:36 AM , Rating: 2
...why does D a i l y T e c h become Da*$#Tech? Does 'ily' mean something? lol.

By JasonMick (blog) on 7/21/2011 10:05:28 AM , Rating: 2
...why does D a i l y T e c h become Da*$#Tech? Does 'ily' mean something? lol.

I'm not sure. :)

But I appreciate the feedback and support.

I know some readers don't like seeing this kind of science coverage due to their personal religious beliefs, but we are a tech and science news site, so it's just something they'll have to learn to deal with. It's nothing personal against them, it's just reporting on the progress of science.

I think it's a good topic to cover because a lot of people are misinformed and think there's a lack of compelling evidence showing the hominid evolutionary path, when in fact there is a wealth of studies and discoveries, much of it very recent.

Good luck in your research!!

"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." -- Bill Gates

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