Ancient footprints show human-like walking began nearly four million years ago

Jul 20, 2011
Computer simulation was used to predict the footprints that would have been formed by the likely printmaker, a species called Australopithecus afarensis

(PhysOrg.com) -- Scientists at the University of Liverpool have found that ancient footprints in Laetoli, Tanzania, show that human-like features of the feet and gait existed almost two million years earlier than previously thought.

Many earlier studies have suggested that the characteristics of the human , such as the ability to push off the ground with the big toe, and a fully upright bipedal gait, emerged in early Homo, approximately 1.9 million years-ago.

Liverpool researchers, however, in collaboration with scientists at the University of Manchester and Bournemouth University, have now shown that footprints of a human ancestor dating back 3.7 ago, show features of the foot with more similarities to the gait of modern humans than with the type of bipedal walking used by , orang-utans and gorillas.

The footprint site of Laetoli contains the earliest known trail made by and includes 11 individual prints in good condition. Previous studies have been primarily based on single prints and have therefore been liable to misinterpreting artificial features, such as erosion and other environmental factors, as reflecting genuine features of the footprint. This has resulted in many years of debate over the exact characteristics of in early human ancestors.

The team used a new , based on methods employed in , to obtain a three-dimensional average of the 11 intact prints in the Laetoli trail. This was then compared to data from studies of footprint formation and under-foot pressures generated from walking in modern humans and other living great apes. Computer simulation was used to predict the footprints that would have been formed by different types of gaits in the likely printmaker, a species called Australopithecus afarensis.

Professor Robin Crompton, from the University of Liverpool's Institute of Ageing and Chronic Disease, said: "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.

"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. 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. We now need to determine when our ancestors first became able to walk or run over the very long distances that enabled humans to colonise the world."

Dr Bill Sellers, from the University of Manchester's Faculty of Life Sciences, said: "The shape of the human foot is probably one of the most obvious differences between us and our nearest living relatives, the great apes. The difference in foot function is thought to be linked to the fact that humans spend all of their time on the ground, but there has been a lot of debate as to when in the fossil record these changes occurred. Our work shows that there is considerably more functional overlap than previously expected.

"The Laetoli footprint trail is a snapshot of how early human ancestors used their feet 3.7 million years ago. By using a new technique for averaging footprints, foot pressure information from modern great apes, and computer simulation of walking in the proposed Laetoli printmaker, we can see that the evidence points to surprisingly modern foot function very early on in the human lineage."

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More information: The research is published in the Royal Society journal Interface.

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kevinrtrs
1 / 5 (7) Jul 20, 2011
Oh dear, another surprise: Ancient footprints are indistinguishable from modern ones. If this is so then it presents a more solid problem for evolutionary thought, namely that with so much time to populate the earth, why are there not many more billions of people and or where are all the graves for the billions who should have died and been buried already?
Even with very short lifespans and generous allowance for catastrophes there should be a lot more people on the earth. So actual population numbers defy this notion that we've been here for millions of years.
ScienceLust
not rated yet Jul 20, 2011
Google image Tanzania.It is the shape of an ape skull.
antialias_physorg
5 / 5 (7) Jul 20, 2011
If this is so then it presents a more solid problem for evolutionary thought, namely that with so much time to populate the earth


Where's the problem? Die-back occurs in populations all the time. Remember that we weren't always the food-chain topping critters we are now. Until quite recently there has been no species (including our own) that has 'enjoyed' an unhindered growth and not the regular predator-prey or environmentally induced fluctuations. Primitive tribes discovered today also do not exhibit exponential population growth.

As for graves: What makes you think that our ancestors buried all their dead 4 million years ago? Or are you also confused about the lack of billions and billions of animal bones (since a lot of aimals have also died since then)

Stuff rots and erodes. Even bones given enough time. To find fossil bones from times that far back requires extraordinary circumstances (like being encased in water/airtight clay by some accident).
Deesky
5 / 5 (2) Jul 20, 2011
Poor Kev, flailing and floundering against the currents of science and reason.
skitterlad
5 / 5 (1) Jul 20, 2011
I say longer than 4 million. What fascinates me the most is that interbreeding must have occurred between hominids that resulted in our current homo sapiens that is really a soup of many. The language center in the brains of all people around the world for babies is the same. So there is a tight link even though people look so different. I'm sure there is much more to unfold in our evolutionary past. As amazing as the big bang.
epsi00
5 / 5 (1) Jul 20, 2011
Even with very short lifespans and generous allowance for catastrophes there should be a lot more people on the earth. So actual population numbers defy this notion that we've been here for millions of years.


That's a lot of hand waving. It's like saying I have the feeling that...How about some equations, if you are up to it, to show that the population should be larger than what it is today. We will allow you a generous number of starting points and a generous number of model of population growth.
thales
4.3 / 5 (6) Jul 20, 2011
Don't bother. Not so much because Kevin's a troll (he is) but because he won't respond. I have yet to see him respond to a single criticism. Just another YEC coward.
Donutz
5 / 5 (5) Jul 20, 2011
I often wonder what kev actually gets out of this. He can't actually think he's convincing anyone of anything. In fact the obvious holes in his logic and education, shown by the tripe that he posts, would tend to reduce the credibility of creotards even more (if that's actually possible). In fact, it gives us a golden opportunity to show just how intellectually (and in some cases morally) bankrupt the creotard movement is.

I've occasionally wondered if kev is actually a biology professor playing devil's advocate just to get people thinking. Trouble is, if he was, you'd think he'd set the bar a little higher.