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Thread: Evolution questions

  1. #1 Evolution questions 
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    Hello everyone!

    This forum is a real blessing to me. I have been a student of the sciences ever since I was a child and have wanted to pursue my collegiate studies in my spare time. I'm sure this forum will be of great help and hopefully I will be able to contribute a few things myself.

    Recently I watched a very informative PBS special that made some very interesting assertions about man's early evolutionary development.

    The first statement was that the consumption of meat is what prompted greater growth and a higher degree of intelligence in the brain's of the homonids. My first question is, if this true, then why didn't the consumption of meat have the same affect on many other meat-eating animals?

    Secondly, it stated that a very particular reason for man's progression to walking upright. It claims that Australopithecus Afarensis began walking on two feet because it saved a modest amount of energy. In fact, they quantified that energy as the amount contained in a single biscuit. The ostensible reason for the extra efficiency was for the sole purpose of being able to recover slightly faster from child birth, thereby allowing a female to produce more children in her lifetime. My question on this is, what evidence is there to support that theory? It seems a bit of a stretch to me, but I would be grateful if someone could illustrate and supportive evidence to this theory.


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    Although I very much agree that evolution is a fact and extremely valid, this part about the progression of man from ape is still very much up to question, not that it happened but the how's and the why's.

    My first question is, if this true, then why didn't the consumption of meat have the same affect on many other meat-eating animals?
    This isn't meant as strictly the meat consumption on its own had an affect on us similar to Mario eating a mushroom or Popeye with his spinach. The affect that meat had on our diets at this time was in addition to our already pretty varied diets. This is actually a pretty well known phenomenon that has been observed in human cultures. In rare times two cultures will come together in the same city or the same place and the diets of each culture broaden. As a result, future generation generally become larger and healthier.

    It claims that Australopithecus Afarensis began walking on two feet because it saved a modest amount of energy.
    You see. I don't like this language, it implies orthogenesis and that Afarensis was sitting around thinking one day about how he could save a little energy. This is wrong. Afarensis did not have a choice on whether or not she walked upright. Just a mutation in the femur neck that Afarensis was intelligent enough to capitalize on. From there she kept reproducing and WALLAH (sp?) the evolution of habitially upright walking apes.

    This must have been the first step to our modern intellectual capacity. Nothing uses its arms like we do, the other apes being the closest but they need them to walk because they don't have the femurs we have. We were already used to using our arms and just because we were walking upright didn't mean we were going to stop using them. Thank God, or we'd all be ostriches and I'd be dizzy from typing. (I hope my point here is clear).

    My question on this is, what evidence is there to support that theory?
    I hear ya here, but you have to admit that if you think about it you can see that there are many more advantages to moving like a human than moving like a chimp.

    This language is a pet peeve of mine. I adore PBS but they are sacrificing reality for a flare for the dramatic with speech like that. Unfortunately, so do many anthropologists. Fortunately, I had a good one.

    Realize that there are very few choices in evolution and that should help you digest that sort of information when its given to you.


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    Hi Silkworm, and thanks for the response.

    I just did a search around the web and came across some other interesting, scientific conjecture. The bottom line however is that it appears is that there really isn't any conclusive evidence to substantiate either point.

    As far as your point about humans having further dietary variety to go along with the meat, there are a number of other creatures in the biosphere that have varied diets, however none of them have developed the same intellectual functions as ourselves. For example, bears are well known to be omnivores and subsist on everything from fish and berries to moose and roots.

    As for walking upright, I saw a great article that basically said the same thing...no one is quite sure. Yes, Silkworm, there are certain advantages to walking upright, however there is a very big advantage in being quadpedal as well: faster movement which allows one to catch prey/avoid predators has got to be top on the list.

    I don't know how, but hopefully someday science will be able to conclusively prove the answers to both of those questions. In the meantime I guess we'll just have to wonder.
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    For example, bears are well known to be omnivores and subsist on everything from fish and berries to moose and roots.
    Yeah, but they can't habitually walk upright so they never had a chance to branch out intellectually. It's hands have never been free to tinker around. Altogether though, the bear is a relatively intelligent creature, wouldn't you say?

    Yes, Silkworm, there are certain advantages to walking upright, however there is a very big advantage in being quadpedal as well: faster movement which allows one to catch prey/avoid predators has got to be top on the list.
    Screw running. Standing and stabbing something in the head with a sharp stick with my free hands is the way I roll. Biped is really the way to go. Makes you taller and makes you look big. Frees your hands. Let's you see. And, if you need to you can still climb trees and humans are pretty fast. Not you and me though, assuming you've been as pampered by technology as I have.

    I don't know how, but hopefully someday science will be able to conclusively prove the answers to both of those questions. In the meantime I guess we'll just have to wonder.
    Actually, I don't see this happening. While we can find out definitively the order of evolutionary changes by tracing back with more fossil finds, exactly why such things become advantageous can't be anything but subjective. And delivering it with the language that has been delivered to you does the whole thing a great disservice.

    Understanding the way human evolution occured and why it occured that way is very much a work in progress and will always be.

    But, it's true that it's all in the hips.
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    The cortex in the brain, that is, the top layer (the thing you see on the normal images of the brain), is in most mammals folded, to give a greater surface area. Now, these folds increase with the size of the animal. Now, a whale requires a very large brain to control all those muscles.

    Our brain has developed to this point, they theorise, as it grew larger, but did not need to steer more muscles. Interestingly enough, the size of our brain is limited due to the size of the woman's vagina.

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    Quote Originally Posted by Mavenmaestro
    As far as your point about humans having further dietary variety to go along with the meat, there are a number of other creatures in the biosphere that have varied diets, however none of them have developed the same intellectual functions as ourselves.
    Interestingly, the only large double-blind scientific study (published inNature) (sample size = 555 African children) found that young children raised on a diet containing meat had IQ's 30 points higher than children raised on a vegan diet. Children raised on a milk diet had IQ's 14 points higher than vegan children.

    http://www.timesonline.co.uk/article...494748,00.html
    http://www.aaas.org/news/releases/20...utrients.shtml
    http://www.nature.com/news/2005/0502.../050221-5.html
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    Hi Maven, very welcome to our forum! :-D You may also be interested in some discussions going on at the biology section (there's one right now about the future path of human evolution).

    Just a small addition:
    - Meat eating indeed made a big difference for the human species. I haven't heard about the connection between intelligence and meat before, but I do know that it was a very efficient way to consume lots of calories in a short time. The discovery of fire greatly enhanced this advantage, as cooked meal is again way more efficient in calories/hour.
    - About walking upright, again I don't know the full story but as far as I know the leading idea is that walking upright made our hands free for other tasks. Such as getting termites from a hole (very good food) as some apes do as well. I think walking upright didn't simply mean that our hands were not in use when walking, but also that they didn't have to be as strong and unflexible (required for walking on them) as before, so we could develop fine motorics.
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    Eat fish.
    Google "aquatic ape theory"
    If you aren't convinced, eat more fish.
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    Vaginal size has nothing to do with birth issues. the issue is the size of the bony opening in the pelvis which allows the infant's head at childbirth to pass thru. That's largely a bony opening in which all sorts of very soft, often very distensible tissues like the vagina reside. As human heads got larger, the pelvis was evolved to a larger size to accommodate this change. Otherwise, the birth would not proceed and the mother would die if not be seriously injured.

    IN males this pelvic opening is small, simply because it's not needed for child birth. And the angle of the symphysis pubis, which is directly related to sex, allows the differentiation of skeletons as to whether, in humans they are male or female. FYI.
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    Regarding eating meat, chimpanzees, our nearest living relative, crave meat and actually go hunting once a month or so. Of course, they are not very good hunters, but any meat they get is shared among them. Like us, they are social animals.

    Also, the polar indians were known to live fairly long lives entirely eating meat. The vast plains of Russia and Western China have a big history of meat eating nomads that preyed upon civilizations.

    We are dependent upon linolitic and linolaic (sp) acids and vit. B12 we must have for our involved nervous system and these are normally only found in animal flesh and of course, fish are also animal.

    On the subject of the vaginal size, can anyone tell me why the pelvis could not evolve larger and thus accommodate an even larger head and brain? My opinion is that it did not need to, that the brain is large enough and efficient enough to make us a very successful species (so far, at least!).

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    Quote Originally Posted by charles brough
    On the subject of the vaginal size, can anyone tell me why the pelvis could not evolve larger and thus accommodate an even larger head and brain? My opinion is that it did not need to, that the brain is large enough and efficient enough to make us a very successful species (so far, at least!).

    chas. brough (http://humanpurpose.simplenet.com)
    the neanderthals had larger brains than us, but i believe the larger brain caused slower reaction times and ultimately, they died out because of that. the size of our brain is very efficient.
    "What do you despise? By this are you truly known" - Frank Herbert
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    Your right, their brain was larger and, as you indicate, it does not mean better.

    We might have a problem with "brain speed" as an explanation of their demise. They apparently lived mostly on hunting and they survived as a species longer than we. (We have been here less than 200,000 years). And it takes brains, speed and skill to kill with tools.

    I suggest that their groups were smaller, such as a single male (perhaps with an aging father and a young brother with the domant male's several females and many offspring. This makes a poorer hunting team than the ten men or so team of a typical hunting gathering group which is and has been characteristic of humans. Their smaller hunting teams made them unable to compete with us.

    Also, we figure that their language was not as well developed as ours. Language is an important vehicle for the developing of the human cultural heritage which enables us to survive in such numbers here on Earth.

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    Quote Originally Posted by RoyLennigan
    the neanderthals had larger brains than us, but i believe the larger brain caused slower reaction times and ultimately, they died out because of that. the size of our brain is very efficient.
    Larger brain size is correlated with higher IQ. A recent MRI study produced rather conclusive evidence of this correlation. But the correlation isn't that strong, and humans with the very largest of brains are morons.

    Large EQ (encephalization quotient, i.e. brain mass/body mass) is better correlated with higher IQ. As discussed above, there are many exceptions however!

    Perhaps equally as important as brain mass to intelligence is brain organization and also the amounts of certain neurotransmitter chemicals produced within the brain. http://www.hhmi.org/news/lahn3.html http://chronicle.uchicago.edu/050106/lahn.shtml There are many studies of this. Perhaps neanderthals were deficient in either organization or levels of certain neurotransmitter chemicals. There is no way of knowing.

    Interestingly, two significant widespread brain mutations are known to have occured in Homo in the last 200k years: the ASPN mutation, among Europeans and Middle Easterners 6K years ago, and the Microcephalin mutation among Europeans and Asians (and N. American natives) about 37K years ago. The ASPN and Microcephalin genes control brain size (which may have increased EQ), and possibly brain organization. Here are some references:
    http://www.newscientist.com/article.ns?id=dn7974
    http://www.sciencemag.org/cgi/conten.../309/5741/1720
    http://hmg.oxfordjournals.org/cgi/co...short/ddh127v1
    Neanderthals of course would not have had access to these mutations.

    Interestingly, at least two species with small brains and also rather small EQ's (about equal to chimpanzee EQ) are capable of suprisingly powerful reasoning ability: Homo Flores (now extinct) and New Caledonian Crows. Both species are dextrous tool makers, tool users, tool planners and teach tool-using cultures to new generations. New Caledonian crows are capable of inventing new tools for new purposes. There is a nice video of this on the web. In both species, the brains and EQ's are much smaller than would be expected to be capable of developing tool bases cultures. A homo sapiens with their small brain size, or their small brain EQ would be an imbecile and hardly capable of basic survival. What this indicates is that the brain organization in these species gave them capabilities far beyond that which would be expected based only on brain size
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    Quote Originally Posted by Mavenmaestro
    Secondly, it stated that a very particular reason for man's progression to walking upright. It claims that Australopithecus Afarensis began walking on two feet because it saved a modest amount of energy. In fact, they quantified that energy as the amount contained in a single biscuit. The ostensible reason for the extra efficiency was for the sole purpose of being able to recover slightly faster from child birth, thereby allowing a female to produce more children in her lifetime.
    I've heard that in fact walking upright changed the female pelvis in such a way that birth actually became more tricky but that the small amount of energy saved from walking upright was enough for us to go along this evolutionary route.


    Quote Originally Posted by charles brough
    The vast plains of Russia and Western China have a big history of meat eating nomads that preyed upon civilizations.
    Really? How interesting, I've never heard of this before. Have you any more info on this?

    Quote Originally Posted by charles brough
    We might have a problem with "brain speed" as an explanation of their demise. They apparently lived mostly on hunting and they survived as a species longer than we. (We have been here less than 200,000 years). And it takes brains, speed and skill to kill with tools.

    I suggest that their groups were smaller, such as a single male (perhaps with an aging father and a young brother with the domant male's several females and many offspring. This makes a poorer hunting team than the ten men or so team of a typical hunting gathering group which is and has been characteristic of humans. Their smaller hunting teams made them unable to compete with us.
    So is what your saying that as long as they didn't have us to compete with their inadequate hunting team they did alright for themselves? I think they lived in much larger groups that you're suggesting, does anyone know?
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    Hello,

    My source is Gimbutas. She was an important archeologist who used her archeological findings to develop a hypothesis that gives a picture of how the people lived North of the Fertile Crescent some 6-8 thousand years ago and on up until historic times.

    Apparently, agriculture stopped at the edge of the dry plains there. It proved useful for people to graze the animals on that dryer land to the north and east. As they multiplied, they had to adjust to living more off the animals as they spread further away from the farmers they traded grain for animals with. Eventually, they spread completely throughtout the region by adjusting to a totally meat-eating diet. It is suggested that they also drank the blood, ate the entrals, and cracked the bones to get at the marrow.

    Gimbbutas called them "Kurgans" and descrabed these pastoralists>nomads as savagely brutal because they adopted an all male god religion and ending the era when it was not yet understood that it took the male to impregnate the female before a could reproduce. The concept was, thus, that the male CAUSED the baby and the mother only incubated it!

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    Silkworm subjects that early humanity went from quadrupedal to bipedal, not only to free the hands, etc., but 'to see'...

    As in the advantage of seeing better from a greater height, what was previously out of sight. Vision being the last refination of the five senses, and, the refination of evolution that lends the most to the potential for complex thinking.

    The original bovine was the now extinct 'Auroch' - they were large and ferocious and roamed the woods like deer. Word is that the bovine animal, the domesticated auroch we now know as cows and bulls, rise up from a prone position, haunches first, then raising the forward part of their body on their two front legs, because: as forest dwelling animals, they could see better looking under the trees that were usually where they dwelled.

    On the other hand, the comparison of the bovine way of rising up from a prone position is the opposite way that equine - plains dwelling - creatures rise up from a prone position. That is, the horse type critter rises up firstly on his front legs, then raises his haunches, because he is a flatland great plains dweller (equus originated in the area of North America that is now about where Idaho, Montana and Wyoming are located) and he can see at greater distances more quickly when he rises up front first.
    The essential point here being that sight - being able to see better - apparently had a lot to do with the evolution of the quadruped to the biped.
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    Quote Originally Posted by RoyLennigan
    Quote Originally Posted by charles brough
    On the subject of the vaginal size, can anyone tell me why the pelvis could not evolve larger and thus accommodate an even larger head and brain? My opinion is that it did not need to, that the brain is large enough and efficient enough to make us a very successful species (so far, at least!).

    chas. brough (http://humanpurpose.simplenet.com)
    the neanderthals had larger brains than us, but i believe the larger brain caused slower reaction times and ultimately, they died out because of that. the size of our brain is very efficient.
    I know next to nothing about evolution.

    I watched a BBC program which I felt gave inadequate evidence to support the fact that Neandethals of the northern hemisphere actually did die out, rather than interbreed with their more psycologically advanced cousins from Africa. I humbly ask if there is genetic evidence to support the entire extiction of Neanderthals. Scandanavians and scots have neanderthal features.
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    Quote Originally Posted by That Rascal Puff
    The essential point here being that sight - being able to see better - apparently had a lot to do with the evolution of the quadruped to the biped.
    You certainly can't say that it is a direct cause and effect relationship, because look at all of the other organisms you have to neglect.
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    Quote Originally Posted by AJ72
    I humbly ask if there is genetic evidence to support the entire extiction of Neanderthals.
    This remains a contentious issue, with evidence supporting both sides of the argument. The weight of current opinion appears to favour the notion that we don't possess any Neanderthal DNA. Perhaps SkinWalker can tell us what the state of play is on this topic.
    Quote Originally Posted by AJ72
    Scandanavians and scots have neanderthal features.
    I rather think not. I was tempted to say "See you Jimmy!" then plant a Glasgow kiss on you, but that would have been unfriendly.
    I can assure you Scots and Scandinavians do not have neanderthal features. I am at a loss to understand why you think they do.
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    Quote Originally Posted by Ophiolite
    Quote Originally Posted by AJ72
    I humbly ask if there is genetic evidence to support the entire extiction of Neanderthals.
    This remains a contentious issue, with evidence supporting both sides of the argument. The weight of current opinion appears to favour the notion that we don't possess any Neanderthal DNA. Perhaps SkinWalker can tell us what the state of play is on this topic.
    Quote Originally Posted by AJ72
    Scandanavians and scots have neanderthal features.
    I rather think not. I was tempted to say "See you Jimmy!" then plant a Glasgow kiss on you, but that would have been unfriendly.
    I can assure you Scots and Scandinavians do not have neanderthal features. I am at a loss to understand why you think they do.
    I might equally tell yae tae watch yar lowland banter, yae sasonach lovin blah, blah. But I'm far too polite for that.

    OK, Hair colour is an obvious one. Why did people in Africa evolve with ginger hair like mine?
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    Evolution seems very simplistic to explain how from tha original soup we evolve into mamals, humans, insects, plants, dogs, fish, virus, bacteria, etc and all the variety between them. We need a new paradigm to explain it better based on new technology and theories. For next centuries Drawinism make look short.
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