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Human ancestors walked comfortably upright 3.6 million years ago, new footprint study says

The views expressed are those of the author and are not necessarily those of Scientific American.


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humans upright walking ancestorsA comparison of ancient and contemporary footprints reveals that our ancestors were strolling much like we do some 3.6 million years ago, a time when they were still quite comfortable spending time in trees, according to a study which will be published in the March 22 issue of the journal PLoS ONE.

Anatomical fossils have given scant confirmation about when our ancestors developed a fully modern gait. Although some researchers have argued that the 4.4 million-year-old ancient human Ardipithecus ramidus ("Ardi") described in October 2009 was adept at walking on her hind legs, many disagree.

So rather than quibbling over badly crushed—and often missing—fossil bones, the researchers behind the new study turned much of their focus back to the famous Laetoli footprints, which were discovered more than 30 years ago in what is now Tanzania. Likely left by Australopithecus afarensis, the same species as "Lucy," these prints show an upright gait, but it has remained controversial just how fluid and modern this creature’s walk would have been.

"Based on previous analyses of the skeletons of Australopithecus afarensis, we expected that the Laetoli footprints would resemble those of someone walking with a bent knee, bent hip gait typical of chimpanzees, and not the striding gait normally used by modern humans," David Raichlen, an assistant professor in the Department of Anthropology at the University of Arizona in Tuscon and lead author on the study, said in a prepared statement.

To test this assertion, Raichlen and his colleagues created a sandy test bed for contemporary subjects to walk across—both normally and then in a bent, chimpanzee-like manner. The researchers used a laser scaner to construct 3-D models of all of the footprints to compare with the Laetoli tracks.

"To our surprise, the Laetoli footprints fall completely within the range of normal human footprints," Raichen said. The upright, modern walkers’ prints had heal and toe-print depths that were relatively equal, as the Laetoli prints do, but those locomoting more like chimpanzees—as ancient humans have been proposed to have done—produced toe prints that were much deeper and did not match the Laetoli patterns.

"This more human-like form of walking is incredibly energetically efficient, suggesting that reduced energy costs were very important in the evolution of bipedalism," Raichlen said.

Image courtesy of iStockphoto/meltonmedia





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  1. 1. new illuminati 10:20 am 03/20/2010

    Uhh… why didn’t they get chimpanzees to walk across the sand?

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  2. 2. jtdwyer 1:03 pm 03/20/2010

    Not to dispute the reported interpretations, but at least one other explanation hasn’t been ruled out: chimpanzees can walk upright – perhaps this hominin also simply chose to walk upright in this case for some good reason, such as the sand was hot.

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  3. 3. rshoff 2:10 pm 03/20/2010

    Since the physics behind walking and the forces of feet against the ground may have been constant throughout our history -as asserted in the article- , we could not know if a different (and so far unknown) ‘gait’ and ‘bone, muscles, tendon’ structure in Australopithecus afarensis relied on similar physics at the point of impact and bears out a similar footprint to modern humans. I’m not saying that it’s not possible that Australopithecus afarensis walked upright with the same gait as we have, but I assert that a footprint is not enough evidence and this is therefore an assumption to be further teased out before publishing results. This hypothesis is just a step along the path of figuring it out, not the end result.

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  4. 4. rshoff 2:21 pm 03/20/2010

    Although I agree that the concept of ‘cousins across the cosmos’ is worthy of contemplation and may very well -hopefully- have a basis in truth, it’s not possible for me to accept that life on this planet has not been at least equally intertwined over the millennia. Therefore, I support the theories of human evolution. The problem is we assert questions and ideas as answers, as in this article.

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  5. 5. JamesDavis 5:47 pm 03/20/2010

    "tharriss": If your mind cannot grab hold of that, then go ahead and compare humans to animals and call us the same. You seem appalled by the idea that humans share ancestors with other animals, as if we are somehow dirtied from the connection. That is amazing arrogance. What is "amazing arrogance" is your narrow mind-set. I gave no insinuation that I or any other human on this planet feels dirty from our connection to our animal companions. We are humans and we evolved from ourself to the stature we are now; the same as the bird evolved from a bird and is still a bird. What is not known is how long we humans have been on this planet. The smart scientists, who have already established a reputation for themselves, said that it is like we just suddenly appeared here 25 thousand years before the Neanderthal suddenly disappeared. They believe that the Neanderthal was here for some sixty thousand years or more and disappeared some 25 thousand years after the humans arrived. Now why would a successful "walk on two legs" animal like that suddenly disappear when human came on the scene? Don’t bother in giving me your elementary explaination because it has no worth.

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  6. 6. way2ec 9:54 pm 03/20/2010

    JamesDavis I WAS going to let tharriss’ comment speak for me but your last comment moves me to add my own. You create more than one black or white scenario in your comments. "The smart scientists" creates a category of "not smart scientists". Insult number one. And I do NOT want to know what criteria you use to judge them. Your first comment uses terms like "lesser animals", "lesser paleontologists" and "lesser scientists". And "go ahead and believe" is like giving me "permission" to believe. Insult number two. In your second comment you leave us with "smart scientists" saying that we "suddenly" appeared 25,000 before Neanderthal "suddenly" disappeared. Well, yes, 25,000 years is sudden in evolutionary terms against a backdrop of 3.6 million year old footprints that indicate some "lesser being" (using your terminology) was walking as we do now. I do agree with you that we are not at the starting point of our existence. But if we are say, in the middle, that gives us another 25,000 years based on your "sudden appearance" (at least using the appearance here on Earth as some kind of beginning point, I assume you imply that humans have an origin further back in time, somewhere else in the Universe) to evolve, right? And if I follow your "Don’t bother in giving me your elementary explaination (explanation?) because it has no worth" line of "reasoning", we are to trace human fossil remains back through time and at some point, poof, there are no more (greater?) humans remains, only "lesser" animal remains? And the Neanderthals are some sort of "lesser human"?… or do you (go ahead and believe, or insist on believing) that the Neanderthals aren’t human at all, just one of the "lesser" animals on this Earth? And as far as DNA analysis, are we the only beings with off world origins? and wouldn’t that show up in our DNA, or are there other "lesser" beings with off world origins here on Earth as well? And "go ahead and believe" whatever you wish to believe, but try to remember, even your opinions have worth, if only to yourself.

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  7. 7. elderlybloke 10:10 pm 03/20/2010

    Dear James Davis,
    It is obvious that you have not read (or if you have, you have not understood) the book by Charles Darwin.
    A small fact that may interest you is that Charlie
    was training to be a Clergyman in the Christian Church before he went off on the Beagle for a 5 year voyage that changed his view about life , the universe and everything.

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  8. 8. elizabetta 12:33 am 03/21/2010

    To James Davis, You said, They believe that the Neanderthal was here for some sixty thousand years or more and disappeared some 25 thousand years after the humans arrived. Now why would a successful "walk on two legs" animal like that suddenly disappear when human came on the scene? My answer is….the same reason so many are going extinct today. Humans destroy other life forms everywhere they go.

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  9. 9. dust 2:29 am 03/21/2010

    My father passed on sometime ago. If human life did not begin or ends with humans, is it possible that he might be looking at my footprint or should I be looking for his. I don’t think I could fit his shoes if I had two life time or a pass life or that other. It’s sad when humans so easly compare themselves to animals. I say thank God for the life I have now and my mother who is still here. Go ahead and say it, thank God, say it like youmean it, thank God!

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  10. 10. aviragess 6:37 am 03/21/2010

    I believe in God – my particular belief system encompasses the idea of the generation of the universe as we know it as an act of ‘sacrifice’ (not as we usually understand it because it involves joy) or put another way, an ‘involution’ into matter of whatever prompts beginnings (or the continuation of steady states for that matter). No big deal either way. As soon as energy is within matter it seeks to express itself intelligently – you have to agree that the systems of matter that function are quite intelligent (I know this is a value judgement, but hey, most of what has gone on here posing as intelligent discourse is full of value judgments). Denying obvious truthes is surely not something that promotes understanding. Of course we evolved on this planet, probably from one celled creatures… (it’s a good narrative, a good creation story/myth) or alternatively: of course we evolved as an off world structure which stimulated local life forms and so on and so forth (pick a myth/story and become emotionally bound up with it) – it’s what primates do, get worked up, but luckily, we’re created out of the dust of stars – just like everything else and that’s a scientific fact.

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  11. 11. JamesDavis 8:50 am 03/21/2010

    "way2ec": Since you are so good at taking sentence out of contex and ignoring certain key words like: "seem like" or "about"…here is you another insult: You show all the signs of being a lesser animal form from the Republican Party era. I think the "more intelligent scientists" species would place you somewhere in the "Tea Party Republican" era.

    If you believe in evolution, you will also have to believe in creation. Something cannot evolve until it has been created. According to lesser and greater scientists, during the big bang era, there were billions and billions, and that is a very low estimate count from the lesser scientists, of atoms spread throughout the Universe. These atoms came together and created cells; billions of different kind of animal cells. One animal cell created the Dog, one animal cell created the "Human", one animal cell created the Neanderthal. The dog, or wolf, since you can’t distinguish the two apart, evolved to the dog we know now. The dog cannot evolve to the Neanderthal, and the Neanderthal cannot evolve to the dog. There is one part of our DNA that prevents us from doing that. That same piece of DNA prevented the Neanderthal from evolving to the Human. The Human cannot evolve from the Neanderthal cell or from the dog cell. Are you starting to grab hold of the picture now "Tea Party Republican" species?

    The Neanderthal animal is a lesser animal cell to the Human animal cell because we Humans "dominated the Neanderthal to extention", the lesser scientist said. But that theory from the lesser scientist is flawed because a greater scientist discovered some Neanderthal DNA in a couple of animal species, that looks similiar to the Human animal species, in Australia and Africa.

    Are you starting to see how the intelligent Universe may be doing things and how the Universe put locks on certain doors to prevent an event from happening and how the Universe allows certain other things to happen when it is time for it to happen? The Universe is smarter than any of its creations and it is ashame we are only as smart as the life forms, like the "Tea Party" species we associate with.

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  12. 12. ambertooth 10:02 am 03/21/2010

    JamesDavis seems to divide scientists into two camps; those whom he claims are the ‘great majority of the smarter paleontologists’, whose point of view he shares, and anyone else whose view diverges from his own, without anywhere supplying sources or statistics to back his statement. Hardly an acceptable standard for erudite debate, let alone admissible science.

    Perhaps, JamesDavis, you would elaborate upon what you mean by your statement ‘we evolved from ourself’. To which ‘self’ do you refer? To support your statement by saying that ‘the bird evolved from a bird and is still a bird’ is both semantically and palaeontologically ludicrous. As I said: elaborate, if you wish to gain some credibility.

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  13. 13. PotatoChip 10:16 am 03/21/2010

    aviragess said: "you have to agree that the systems of matter that function are quite intelligent"

    No I don’t.

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  14. 14. aviragess 12:07 pm 03/21/2010

    So Potatochip – can you elaborate? If not ‘intelligent’, how about functional? Because it does of course function. It may take a low common denominator approach (from the hominid point of view which is keen on shortcuts) but it does come up with results – and often by ‘shortcuts’, mutation, quantum shifts of energy etc. That’s why I allowed myself a little humour via a value judgement. Because naming something as being intelligent is of course being anthropomorphic. But maybe your disagreement was full of humour too? Or maybe just referring to the problem of anthropomorphism? It’s hard to tell on the net.

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  15. 15. PotatoChip 1:30 pm 03/21/2010

    Aviragess, I was hoping it was clear that my primary disagreement was with your phrase "you have to agree". I’m less interested in debating the rest. I wouldn’t use the word "intelligent" to describe "systems of matter that function" (yes, it’s anthropomorphic), but you are certainly free to.

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  16. 16. dalestephens 4:00 pm 03/21/2010

    YES.

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  17. 17. dalestephens 4:00 pm 03/21/2010

    YES.

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  18. 18. dalestephens 4:01 pm 03/21/2010

    Yes.

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  19. 19. scientiaveritas 6:26 pm 03/21/2010

    This is the dumbest article I’ve read on scientificamerican.com. Obviously these are modern human footprints as Raichlen proved scientifically. This shows a flawed dating system not anything significant about human evolution. They were not made 4 million years ago because the dating systems used on these footprints yield enormously ancient dates Why is accepting this obvious fact never an option? because the modern geologic column has to be right or else everything falls apart. Time for science to be honest with itself.

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  20. 20. scientiaveritas 6:27 pm 03/21/2010

    This is the dumbest article I’ve read on scientificamerican.com. Obviously these are modern human footprints as Raichlen proved scientifically. This shows a flawed dating system not anything significant about human evolution. They were not made 4 million years ago because the dating systems used on these footprints yield enormously ancient dates Why is accepting this obvious fact never an option? because the modern geologic column has to be right or else everything falls apart. Time for science to be honest with itself.

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  21. 21. aviragess 7:16 pm 03/21/2010

    what a spirit of enquiry.

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  22. 22. way2ec 9:01 pm 03/21/2010

    JamesDavis, uhh, tea party as in Alice in Wonderland, maybe. I don’t even live in the United States. Uhhh, I think I can see Russia from here, NOT. Jumping from comments on evolution to Tea Party Republicans!!! Next stop, the evolution of WASPs through Hippies, then Yuppies, and where on your evolutionary tree of intelligent creationism will you hang "The One", President Obama? No insult taken, I can’t stop laughing. Someone, PLEASE thump me on the head with a Bible. The footprints? Maybe Noah after the flood, or the repopulation of the world (through incest) as his family were the only humans that survived. Same problem before the Flood, starting with Adam and Eve. Cain killed his brother Able, no mention of daughters, incest or cloning?, no, the arrival of humans fully formed, intelligent (of course) from… oh now I get it, STARDUST! Intelligent Creationism? The joke’s on you buddy. And if you are one of the "greater" thinkers, than I KNOW I must be one of the "lesser". Would you believe I am from a long long line of rednecks? Geez, what makes you think I am even a white guy? Republican Tea Party? Alice, oh Alice… we aren’t in Kansas anymore. I’m Tonto (Spanish for fool, or stupid) and you JamesDavis, are the Lone Ranger.

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  23. 23. Squish 2:34 am 03/22/2010

    Let me quote a wise man, Roger Ebert: ‘Resentment is allowing another person to live in a room in your head for free’. I bring this up because I can’t help resenting the comments, incessant and unfounded, that really stick to me; I end up reading more about what Intelligent Designers think than what recent research can offer us.

    Yet my intention was to read about some science. I don’t know why I have to read all of JamesDavis’ comments, I dislike them, but yet I am compelled to. And don’t reply JamesDavis – it isn’t because I am uncomfortable with the ‘truth’ that ‘greater scientists’ have to offer. It is because all of your statements are conjecture and belie a personal agenda that seems apart from furthering Scientific Knowledge. Of the statements, none (besides keeping possibilities open for testable hypotheses) are part of the scientific method.

    Ancient dog cells becoming dogs? Ape cells? Do you know that DNA can be extracted from the nucleus of a differentiated cell and implanted into an egg cell? Or that DNA can be cut and inserted? Or that mutations happen? Or that we can witness DNA changing predictably according to the environment? What about domesticated Grey Foxes, what cell did they come from?

    Plato philosophized about universal ‘forms’, or ideals of things more real than the actual objects. That there was Absolute Beauty, for example. Early Christians believed in this kind of thinking – deducing from assumptions, based on the Bible – and called it Scholasticism. Logic was involved, yes, but we have since moved on to observation, controlling, experimenting and inducing.

    Some posters have their own pre-set beliefs and are deducing from such dogma. I resent this. Let’s keep this area open – but not open to poetry, or hearsay, or bias, or doctrine, or Forms, or Scholasticism, just for the sake of being open – but open to quantifiable predictions that can be tested using the Scientific Method, that will yield information that can be replicated and applied towards the field of accumulative knowledge known as Science.

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  24. 24. way2ec 2:43 am 03/22/2010

    THANK YOU Squish. Thank you for returning us to the topics of scientific knowledge and scientific methodology.

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  25. 25. westokla 9:09 am 03/22/2010

    So well said :-)

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  26. 26. westokla 9:19 am 03/22/2010

    Live and learn. Here I thought that birds evolved from Archaeopteryx into early birds and then into our modern birds. I guess this is an error since you state birds evolved from birds. :-)

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  27. 27. JamesDavis 9:22 am 03/22/2010

    "Squish", how boring and disappointing it was to read your non-scientifis, "point of the nose" comment. You can’t seem to see beyond the poing of your nose.

    Ancient dog cells becoming dogs? Ape cells? Do you know that DNA can be extracted from the nucleus of a differentiated cell and implanted into an egg cell? Or that DNA can be cut and inserted? Or that mutations happen? Or that we can witness DNA changing predictably according to the environment? What about domesticated Grey Foxes, what cell did they come from?

    If you weren’t stuck somewhere in your own little Universe, you’d know that they did not have cell splicing or egg emplantation on this planet during the forming of life from the cells that represent each species. I may be wrong, or you could be just totally wrong, but isn’t the fox in the same K9 family as the common dog?

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  28. 28. eeburrah 9:45 am 03/22/2010

    rather than asserting that the article is wrong and that you’re right, how about providing evidence? or proof? or maybe even something to back up your claim. that’ll work, thanks.

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  29. 29. PotatoChip 11:30 am 03/22/2010

    It would be a shame if this forum were derailed by the likes of JamesDavis. It’s quite clear to everyone else (from those who value critical thinking and clarity of expression to those who come here to articulate their religious position in the form of poetic offerings) that the comments written by JamesDavis are best described as incoherent nonsense. Everything Squish said was dead on. I suggest that we proceed with this understanding, and that it isn’t necessary to endlessly refute what everyone else can clearly indentify as unintelligible gibberish. Or, if you wish to rebut him, do so knowing that he is an army of one and that the community of reasonable thinkers has your back.

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  30. 30. Andira 7:32 pm 03/22/2010

    There is an obvious reason why God can not be, scientifically speaking, a factor in evolution, or in creation for that matter, and it has nothing to do with bias or intolerance but with the basis for scientific methodology and the nature of science as such. Science seeks explanations which are rooted in the causal factors of nature, solely. If a scientist could put in God whenever his theories have a gap, then other scientists could do the same according to their likes and dislikes, and the system would quite simply crash. And without doubt this strategy has so far proved eminently successful, successful enough to change civilization completely. The Copernican Revolution is over, people, and so is Darwins continuation of it. The Earth moves, and we are intelligent primates.

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  31. 31. jack.123 8:12 am 03/23/2010

    First I am not saying God exists,because I don’t know.Darwin’s theories have some pretty big holes in them as well,Having read the Bible I have found no where in it that says God didn’t use evolution.From what science tell us about the true age of there Earth,the development of even simple life took a very very long time.Billions of years passed before multi cell life forms began to take hold.We know this to true,because atoms decay at a very certain rate,and theses rates give us a very accurate age of the planet.
    Now I know that there are some believers out there at this point that are upset,but please read on.I am now going to a different place in the Bible.Moses is on the mountain,and God is telling him to take his shoes off.Why might you ask?Well it is because he is on holy ground,and the shoes have been made by man wherein Moses bare feet were made by God.That point being made,Since the Bible is penned and bound by man it is no more perfect than Moses’s shoes.The errors thus found in the Bible are not Gods but mans,and the book is thus not perfect.Now for the age of the Earth,Jesus said that one of Gods days is as if a 1000 of our years long.Note he didn’t say exactly,because he was just trying to make a point that you can’t use the Bible to tell how old the Earth is.Or for that fact to be certain about time flow in the book.In fact Jesus was the first to describe time dialation.It would take another 2000 years before another great man would say time is relative to the observer.
    Now let us go back to the first book,and on the sixth day God created man in his image,note that Adam was not created till the eighth day.Now how much time happened between the two we can’t tell,but on that sixth day.The first covenant was made,as follows I give you all seed bearing plants to do with as you feel and domain over all other life.This included the first two commandments,Be fruitful and multiply.
    Now lets look at what made theses men dominant,only one thing stands out,and that is fire,and science tells us that fire was in use by the species that preceded us,in other words the first covenant with God was with the species that preceded us.and God didn’t seem to have any trouble with mankind till Adam came along.Since I don’t have a Bible in front of me please don’t quote me,please read the Bible for your self.If you find me in error please respond.Because this all just a theory.

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  32. 32. PotatoChip 8:46 am 03/23/2010

    jack.123, please itemize the "pretty big holes" that you think exist in the principles of evolution by means of natural selection.

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  33. 33. ambertooth 11:48 am 03/23/2010

    jack.123: "Having read the Bible I have found no where in it that says God didn’t use evolution."

    Hardly surprising, jack.123. The concept of evolution in nature obviously was unknown to the (largely unidentified) writers of those ancient texts. So referring to the Bible for a did/didn’t answer about that or many another matter serves no useful purpose. I wonder, truly I do, whether or not it is possible to discuss such a subject as this article outlines without the attached comments thread becoming clogged with those who evidently feel that their religious beliefs are a part of the issue.

    So, jack.123, why do you apparently deem it necessary to raise the subject of the Bible at all in such a context? How is it relevant to the science?

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  34. 34. Ungolythe 3:19 pm 03/23/2010

    I’m not trying to answer for jack.123 but I believe I know from where he is coming. I too feel the same impulse to proactively counter some statements that young earth creationists seem to believe is proof that evolution does not exist: it is not in the Bible. The Bible is a great source of inspiration so it’s only natural to try to fit what we have learned from science into the context of biblical teaching.

    There are holes in the theory of evolution. One is a lack of explanation of the cambrian explosion. That only shows that the theory is imperfect and incomplete and we all know that already.

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  35. 35. PotatoChip 4:14 pm 03/23/2010

    Ungolythe, the Cambrian explosion represents much less of a "hole" in evolution theory than the motion of galaxy clusters represents a "hole" in gravitational theory. If you ask an evolutionary biologist (from let’s say Harvard, Princeton, Yale, Berkeley, Stanford, Dartmouth, etc.) whether the Cambrian explosion should lead anyone to say that natural selection might not be the mechanism at work, what do you think he would say? Current evidence shows that there was nothing sudden about the explosion, and that the time frame for the evolutionary radiation of the period is considered to be completely consistent with the principle of gradualism. It’s simply untrue that it happened all at once.

    The Cambrian explosion does NOT show that the theory is imperfect and incomplete. It may be imperfect and incomplete, but the Cambrian explosion is not evidence of this.

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  36. 36. ambertooth 5:31 pm 03/23/2010

    Ungolythe: "The Bible is a great source of inspiration so it’s only natural to try to fit what we have learned from science into the context of biblical teaching."

    For whom? Surely only for *those who accept the Bible’s scriptural authority. Perhaps only those who feel insecure about their ‘faith’ attempt to support it with the supposed respectability which they perceive science as providing. Faith is about taking something on trust – not reinforcing it with the methodology of science. So I ask you the same question, Ungolythe, which I asked of jack.123: why mention the Bible at all? What does the Christian faith have to do with the relevant science here?

    *Remembering that this is an international website, and the extent of the Bible Belt is more limited than provincial horizons tend to imagine.

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  37. 37. Ungolythe 6:46 pm 03/23/2010

    Just because I say that the theory is incomplete and imperfect does not mean that Idon’t believe in it’s basic principles are at work. The fact is that current evolutionary theory does not easily address how life evolved from single cellular organisms to the complex life that appeared in the Cambrian. Please don’t think that to mean that I am of the Intelligent design "faith".

    ambertooth, it is mentioned because as I said: "I too feel the same impulse to proactively counter some statements that young earth creationists seem to believe is proof that evolution does not exist: it is not in the Bible." That does not mean that I am mentioning the Bible has any real relevance to evolutionary theory. I might ask you why you get so hostile when the Bible is mentioned? Sure enough there are plenty of different faiths and I respect them all, well most of them at least, do you? Surely you are not at the other of the spectrum of those who believe that there is no place for evolutionary theory in their faith. You know the ones who can’t comprehend that someone can believe in science and evolution and still believe in the underlying principles outlined in the Bible?

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  38. 38. PotatoChip 8:35 pm 03/23/2010

    Ungolythe:

    jack.123 said, "Darwin’s theories have some pretty big holes in them." He said this in direct reference to whether God "used" evolution. I interpret him to be saying that wherever scientists haven’t mapped out every step of every evolutionary lineage, then there is room for declaring that God was involved in making it happen.

    Now if your point is that in the coming decades, researchers are likely to understand the mechanisms of evolution better than they do now (such as how they now understand how small changes in regulator genes can have large consequences in gene expression), then it’s just a normal part of science. The same can be said of any branch of science, such as inflationary cosmology or quantum theory. No one would argue that those branches are complete. There is as yet no theory of quantum gravity. That would be a "hole" in our knowledge. And yet, it’s not a "hole" as jack.123 means it.

    So, if that is what you mean, then you completely disagree with jack.123 when he implies that the holes in our understanding encourage us to think that God resides and intervenes in those places.

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  39. 39. ambertooth 6:50 am 03/24/2010

    To Ungolythe: you seem to defensively interpret my remarks as ‘hostile’. If you read what I said, I am trying to get a straight answer as to why it is necessary at all to introduce religious belief into this topic. Read back through this thread. It is supposed to be about the degree of bipedal stance in hominins. So why do jack.123 and yourself introduce the Bible and its teachings as apparently relevant to the topic in the first place?

    By the way, the Cambrian explosion lasted many millions of years, and was only an ‘explosion’ in the sense of the diverse radiation of different organisms, not in the speed at which it happened, which is easily within feasible diversification of taxa. The fact that you seem to find it necessary to trot out this hoary old creationist chestnut, for whom it also is a ‘hole’ in evolutionary theory, is rather suspect in itself. I have only ever come across the mention of the Cambrian explosion in this misguided context on creationist websites, and from the mouths of creationists. Perhaps you are an exception.

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  40. 40. jack.123 7:00 am 03/24/2010

    As a response your points Potato Chip,and my statement that the lack of use of evolution couldn’t be found in the Bible was because there are people trying to use the book to dismiss evolution all together,I am not.The cambrian explosion is one such hole that I was talking about,the appearance of flowering plants is another.Random and or chance events simply can’t explain how fast these and other things happened.Now just because what is going on can’t be explained,doesn’t mean evolution is wrong, it just means the theory is incomplete,and you don’t necessarily need God or intelligent design to fill the gaps,but one thing is clear something else is go on that we don’t understand.I have a theory that it is life its self,experimenting using molecular memory in the same way instincts are stored in both DNA and RNA,using this method,different ways of doing things could be done without waiting for random events to occur.Just how this might play out will require a lot of research,but I believe a lot of the answers will be found in what they call junk DNA and RNA.I am getting a little tired.I will discuss quantum gravity,at a latter date.I eagerly await your response.

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  41. 41. PotatoChip 8:22 am 03/24/2010

    jack.123, I believe I parsed your sentence correctly, although it may be that you didn’t mean it the way you said it. In refuting evolution denialists, you were clearly proposing (at least according to the semantics of your statement) that maybe God causes evolution.

    Regarding the Cambrian explosion, see ambertooth’s response above. As for the appearance of flowering plants – well I just don’t know what to say. I don’t know where you get this stuff from. Maybe ambertooth is right that you and Ungolythe get your information from creationist websites. You aren’t getting your information from people who are trained in the related scientific fields.

    When you say, "Random and or chance events simply can’t explain how fast these and other things happened", you reveal the extreme degree of your misconceptions. I suggest you read a book about it. I suggest, for starters, Jerry Coyne’s recent book, Why Evolution Is True.

    Link to this
  42. 42. jack.123 9:08 am 03/24/2010

    Thank you for your suggestion I shall read Jerry Coyne’s book Why Evolution Is True.

    Link to this
  43. 43. Ungolythe 3:00 pm 03/24/2010

    Nowhere in my statment did I imply that the Bible had any revelance to this discussion. It was merely mentioned by jack.123 as a prophylaxis against those who would. I was miffed by the tone and tenor of your reply "…For whom? Surely only for *those who accept the Bible’s scriptural authority. Perhaps only those who feel insecure about their ‘faith’ attempt to support it …Remembering that this is an international website, and the extent of the Bible Belt is more limited than provincial horizons tend to imagine."

    It appears that you saw the work Bible and made some incorrect assumptions. I too feel peeved when someone tries to use the Bible to prove anything relating to science. Just the other day a co-worker told me that he knew that the idea that the universe is billions of years old is a complete myth. He said he could PROVE that the universe was actually only 6500+ years old with the Bible. I just rolled my eyes and said we would have to carry on the discussion after work.

    Link to this
  44. 44. ambertooth 6:39 pm 03/24/2010

    To Ungolythe: well, you might be ‘miffed’ with my tone. But you were the one who raised that cock-eyed misconception about the Cambrian explosion, which in several years of debating them on the Internet I have never before heard anyone but a creationist utter. At best, if you seriously are putting forward the Cambrian explosion as a flaw in evolutionary theory (which you are, because it’s right here on this thread for all to read: your comment at 03:19 PM on 03/23/10), then your basic knowledge of the subject is frankly shocking. I note that nowhere in your latest comment to me do you even mention this part of my response to you.

    And now I’ll take a different tack: this thread should be discussing the range of bipedal stance and locomotion in hominins, which is what is relevant to the accompanying article. I and other voices here, as well as, I am sure, the SciAm moderators, would prefer to stick more to that. Having been involved professionally with the restoration of A. afarensis, my own point of view is that A. afarensis was fully bipedal (footprints or not, the pelvis is a giveaway). Since A. afarensis was not human, then full bipedalism was already developed before these hominids evolved to become us (to put it simply). To put it as simply: fossil primates were walking fully upright, and such a stance cannot be considered uniquely ‘human’ as such – as something which ‘sets us apart’ from other primate species.

    In fact, of course, bipedalism is nothing remarkable or unique anyway. Maniraptoran non-avian dinosaurs were obligatory bipedal, as their contemporary avian forms continue to be, notably the flightless varieties – the rhea and ostrich come to mind. Even among the ornithopods, the hadrosaurs were at least nominally bipedal. So bipedalism as such is certainly not something which marks out the human species, or even our fossil precursors, as ‘special’.

    Maybe Ungolythe and jack.123 would care to offer their opinions about the above.

    Link to this
  45. 45. Ungolythe 12:15 pm 03/25/2010

    Ambertooth, thank you for steering this back to the original topic. It was an unneccessary diversion for us to have been sidetracked on silly non-issues regarding semantics. I was merely pointing out that that our knowledge is incomplete on the subject and not interjecting some divine influence.

    Regarding the actual topic. Do we have any fossil footprints of hominids that are running? One would assume that if they were bipedal they would be similar to our own toe to heel step pattern that barefoot runners exhibit.

    Regarding the experiment, do we know if the experiment was done using habitual shoe wearers or those who rarely wear shoes?

    Link to this
  46. 46. ambertooth 6:13 pm 03/25/2010

    Ungolythe: "It was an unneccessary diversion for us to have been sidetracked on silly non-issues regarding semantics."

    It was jack.123 who tied himself in a semantic knot talking about ‘birds evolving from birds’. It was yourself who raised the subject of the Cambrian explosion being a ‘hole’ in evolutionary theory. This topic, however, has nothing whatever to do with the integrity of evolutionary theory, and you yourself could have brought this thread back on track anytime by commenting earlier as I have now done. You chose not to.

    As to the rest of what you ask me, I am sure that you are as capable as I am of chasing down the answers which you seek (although at the time of this comment the PLoS ONE site is down for maintainance). So I suggest that you do so. My understanding, however, is that the Laetoli tracks were made by hominids walking (not running) over volcanic ash.

    If you are sincere in wanting answers to your questions, then rather than getting someone else to do your legwork for you, contact the author of this article. But that’s only, of course, if your questions are indeed sincere lines of enquiry.

    Link to this
  47. 47. anrika411 11:24 pm 03/27/2010

    How would the footprints of Australopithecus afarensis compare with those of Homo floresiensis if and when such footprints are discovered? I have read articles which state that the foot bones of the Hobbits were primitive and that this species must have had a less efficient upright gait compared to that of modern humans. If this is true, does it mean that the species from which H. floresienis descended was more primitive than Australopithecus afarensis?

    Link to this
  48. 48. mo98 3:13 am 03/28/2010

    What’s interesting to me is that for about a hundred dollars, a shoe can be made that measures the distribution of pressure of the foot inside it and is able to signal an early warning about the user who may be unwittingly prone to getting a stroke or some other tell-tale ailment that affects balance in bipeds. Credibility is in the evidence of related application, assuming no haste was made in footprint dating.

    Link to this
  49. 49. Darnellious 12:01 am 03/30/2010

    A monkey wouldn’t work for what they were paying.

    Link to this
  50. 50. PotatoChip 8:13 am 03/30/2010

    Darnellious: chimpanzees aren’t monkeys.

    Link to this
  51. 51. Jasonblu 9:47 pm 08/15/2011

    It amazes me how ‘science’ (falsely so called) misses the forest for the trees. This finding a grand case in point. These ancient footprints prove what sane scientists have been saying all along: “Humans didnt evolve”. They were created human. I chuckle at all the lame attempts to try and explain this clear, obvious evidence…that even this far back humans walked just as they do today, because, silly unbelievers…they were humans just like you and me today.

    Link to this
  52. 52. Jasonblu 10:08 pm 08/15/2011

    I know the majority of you atheist religion types (as yours IS just another religion – a belief system founded on the unseen – in your case the BELIEF that a strange cosmic egg that just happened to exist with no beginning or creator ‘exploded’ and then accidentally created the universe) won’t be able to handle this but the following article is really the only sane conclusion to the ‘mystery’ of the Laetoli tracks. http://www.icr.org/article/6266/

    Link to this

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