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Stone Age

  1. Dec 5, 2004 #1
    Human genes evolved for the stone age. Therefore we must adopt
    stone age habbits if we want to stay healthy, how true is this statement?
     
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  3. Dec 5, 2004 #2

    iansmith

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    Gene did not evolved for the "stone age". Certain genes were selected for during the "stone age" because it allows certain individuals to live and reproduce more.

    Of course our modern day living habits are a bit different for certain populations. We have constant food supply and are less active. We might want to adopt certains habbits that will decrease our food supply at any given time and start to be more active. However, not all habit used in the "stone age" would be good because modern human have, to a certain extand, adapted to its sedentary live style.

    I would says it is false.
     
  4. Dec 5, 2004 #3
    I think this is false too because our environment is always changing and we have to constantly adapt to new situations otherwise we won't survive and only the fittest are selected by nature. Just because our genes are from stone age by having stone age habits will probably be a disadvantage.
     
  5. Dec 6, 2004 #4

    Phobos

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    The statement assumes that human evolution stopped in the stone age, which is not true. Evolution keeps going. The human gene pool is different now than it was in the stone age. Granted, we are still the same species and some of the human traits then are still relevant today. But keep in mind that humans have mixing of pre- and post-stone age genes.

    You must also wonder about the statement of "being more healthy" when the average life expectancy was something like 25 years old (lower?) in the stone age vs. an expectancy of 75 years now.
     
  6. Dec 10, 2004 #5

    Nereid

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    It may be more useful to first ask what habits tend to maintain good health in homo sap. individuals. But the very question hides others, e.g. what is 'good health'? how important a component is 'mental health' in 'good health'? where does 'happiness' fit?

    There are, of course, quite many clear results of the kind 'what habits tend to NOT maintain good health?'! And several of these may be compared to what we infer to be the lifestyle of our ancestors, over 100,000 years ago. OTOH, many can't.

    Personally, I'm fascinated that even when it's overwhelmingly clear that certain habits are bad for one's good health (e.g. smoking), many people persist with them, even though they are fully aware there's a vast amount of help available to assist them quit.
     
  7. Dec 10, 2004 #6
    I think its a bit like a graving for fat foot (which on the long run is bad) which will ensure survival for a longer period of time in harsh environments (so for the short run its good). Remember evolutionary preasure stops around 40 years of age.

    I think theres truth in the statement that started this post in the sense that human evolution took many thousands of years and our eating/living habits changed dramaticly in the last say 3000 years let alone the last 100 years. The question is, is the human body evolutionary fit to drink cows milk for instance and vitamin supplements and large amounts of vetgetables. I agree that now life expectancy is much higher than back then but there are multiple factors causing that.
     
  8. Dec 11, 2004 #7
    This statement (or question) is absolutely absurd. Our environment changes, individuals within our species have mutations, the environment selects advantagous mutation, which are manifested through increased reproductivity. Then over time our species evolves with the environment. Why then would we try to maintain habits of our species who lived thousands of years ago.

    Would we be healthier if we crawled along a muddy swamp? Would we be healthier living on the ocean floor? Where in our evolutionary past shall we go in order to be healthier.

    Now with that being said. The most fit of our ancestors had the ability to store a great deal of fat. For insulation, protection, and most importantly for energy sources in times of need. Therefore, the individuals, which make up our species now, have been adapted to store fat. In the last few hundred years our species (at least in industrialized nations) has an over abundance of food, while still maintaining the ability to store fat and a major drive to eat.

    If the industrialized nations were blocked off from the rest of the world and obese individuals had a reduced capacity to pass offsprings, then eventually our species would loose the ability to store fat. I have seen studies, which show that obese individuals do pass on less offspring, so the possibility is there. EXCEPT for a couple of issues: othe parts of the world do not have an abundance of food and I am sure we will either find drugs to prevent obesity or blow up the world before we evolve into a skinny species.

    Back to the original question. If it insinuates that we need to work out, then yes.

    Nautica
     
  9. Dec 11, 2004 #8
    I think Nautica already said it well, but to add a bit (of more or less the same):

    Back in the stone age there was natural selection, and also nowadays there is natural selection. However, because our environment has changed enormously, nature nowadays selects other phenotypes than it did in the stone age.

    Our current make-up results from what was selected in an ancient environment, which is different from the environment in which we live today. Therefore, it may not be the most healthy choice to simply assume that whatever feels good, like fat food, must be good. Those feelings indicate what was good in an ancient environment.
     
  10. Dec 11, 2004 #9
    What kind of habits qualify as Stone-Age today? Possibly Flintstone-type lifestyles?
     
  11. Dec 11, 2004 #10
    The original question of this thread is a good one. It's one I've studied for about 4 years now. There have been several common misconceptions expressed in some of the replies. The answer is our genes, as the substrate of our physiology, evolved for stone age life. Therefore, adopting stone age lifestyle habits would improve our health in many ways. This is much trickier than would seem.

    Humans are photoperiodic, as are all mammals. As our modern environment severely alters the natural photoperiod our physiology is negatively impacted. This single fact of physiology explains most "health disorders" so common in developed countries today. The list of photoperiod disorders at least include: obesity, fertility/reproduction, hypertension, hair disorders (including pattern baldness) and many internal cancers. If you don't know what photoperiod is go to scholar.google.com and do a search on photoperiod. An exhaustive amount of information on the subject can be found there.

    The bottom line on photoperiodism is that it shows humans are still biologically in the stone age, we have not evolved to adapt to life in the modern/artificial environment. If we had, as many claim, we would look dramatically different than we do now as a species. But, that's another discussion for another thread so I'll end my reply here.
     
  12. Dec 11, 2004 #11
    You may have a point. We will design an experiment. Lets pretend that we are back in the IceAge. Lets take 100 people, sell our houses, sell our cars, sell our clothes, and take a plane up to the artic. Lets get out of the plane and begin a new life.

    Somebody should come check on us in 10 years and see how healthy we are compared to the control group who stayed home.

    Seriously, nobody is denying the fact that we are over indulging. We eat to much, work to hard, play to hard, do not get enough sleep or the right kind of sleep, I could go on and on and on. But, natural selection is still at work, we are still evolving. The thing is that evolution does not take place over night. In 100,000 years from now, our species will be different, it may not even be considered the same species. The entire reason species evolve is b/c nature selects on mutations. Nature is now different so it is making different selections. The problem is that in the industrialized world we are somewhat protected from nature so its power is not that great, but this protection we have will begin to make selection.

    For example, I mentioned earlier a study was done, which showed that obese individuals produce less offspring. This is a classic example of natural selection and as the problem becomes more prevelant this selection will become more obvious and in 1000s of years from now there will be no more obese people.

    And before anybody jumps on this one. I know that only a small part of the world is industrialized, I know that drugs will be introduced possibly to combat this, and I know that most likely we will destroy our planet before this happens. I was only using a simplified example to help explain my point.

    Nautica
     
  13. Dec 11, 2004 #12

    Nereid

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    Are there any humans whose environment does not severely alter the natural photoperiod, with physiology not (much) negatively impacted? For example, there are still a few million who live a life of hunting and gathering, and a few more million in nomadic herding.
     
  14. Dec 11, 2004 #13
    Good point. Let me clean this experiment up, take it one step further and give you the results. First, all races should be present in the sample groups and each race should be represented by at least one couple. Second, there should be several of these groups dropped off at various latitudes from the equator to the artic circle in areas free from any modern environments. Here are the results:

    @ +/- 60 degrees: blondes/blue eye's are fairing the best
    @ +/- 40 degrees: olive skin/ brown eye's are fairing the best
    @ +/- 20 degrees: asian's are fairing the best
    @ +/- 0 degrees: black's are fairing the best

    Please don't misunderstand me, I'm not saying this is where people should live today!! I'm just saying this is where the races came from as a result of evolution - it's a an excellent match between physiology and environment. The real problem today is that EVERYONE in the modern world is POORLY matched to the artificial environment we've created AND as a result of massive transcontinental migrations and cross-breeding there are very few populations that are "pure" results of stone-age evolution.

    Well I'm in partial agreement with you here. It's clear that natural selection is at work in terms of thinning the herd, meaning those who are the most poorly matched to the environment are dying off before producing significant numbers of offspring. Let's call this "natural deselection". The other part though seems to be wholely absent, that of genetic mutations and the like leading to improved biological function. Let's call this "natural progression". I see absolutely no evidence of it. At best it could be happening in a few isolated cases but other pressures (e.g. socio-cultural) don't seem to favor the eventual outcome. What's really happening in my opinion is just a large-scale variation on our experiment above. The result is going to be some people are simply better suited, as a result of their inherited stone-age characteristics, to life in the modern world than others. So, in summary I agree with you that there's plenty of evidence to support the claim that "natural deselection" is occuring but very little to support the claim that "natural progression" is happening. It takes both for us to make it.
     
  15. Dec 11, 2004 #14
    Any culture that uses artificial lighting at night, including fire, in fact over-rides their own biological programming. By that standard there aren't any populations that have had "pre-historic" lifestyles for a very long time. Still some come much closer to the ideal, like those you've mentioned, and the health plagues of the modern world are largely absent there. Have you heard of an obesity epidemic among Mongolian herding tribes? I haven't, but if one comes take a look for "improvements" in their living quarters!
     
  16. Dec 11, 2004 #15
    "Well I'm in partial agreement with you here. It's clear that natural selection is at work in terms of thinning the herd, meaning those who are the most poorly matched to the environment are dying off before producing significant numbers of offspring. Let's call this "natural deselection". "

    No, let's not.


    The other part though seems to be wholely absent, that of genetic mutations and the like leading to improved biological function. Let's call this "natural progression".

    Once again, No, let's not. Natural selection is what it is. Mutations occur. Most are nuetral and nothing happens. Some are deliterious and causes harm. Others are beneficial, especially in a novel environment and those that were nuetral, have also had a chance to mutate farther and, once again, in a novel environment they might prove to be beneficial. If by some chance this improves the fitness of the individual and other individuals, then evolution has the chance to occur. So, let us use the name it was originally given over 100 years ago. Natural Selection.


    "I see absolutely no evidence of it. At best it could be happening in a few isolated cases but other pressures (e.g. socio-cultural) don't seem to favor the eventual outcome. What's really happening in my opinion is just a large-scale variation on our experiment above. The result is going to be some people are simply better suited, as a result of their inherited stone-age characteristics, to life in the modern world than others. So, in summary I agree with you that there's plenty of evidence to support the claim that "natural deselection" is occuring but very little to support the claim that "natural progression" is happening. It takes both for us to make it."

    As far as the rest of your post goes, it sounds like you are unable to see the forest for the trees. You are speaking of Natural Selection.

    Nautica
     
  17. Dec 11, 2004 #16
    A bit harsh but fair enough. Let's go to the source, Darwin himself:

    http://www.literature.org/authors/darwin-charles/the-origin-of-species/chapter-04.html

    From Chapter 4, Natural Selection, Summary of Chapter:

    "This principle of preservation, I have called, for the sake of brevity, Natural Selection. ... Natural selection, as has just been remarked, leads to divergence of character and to much extinction of the less improved and intermediate forms of life. On these principles, I believe, the nature of the affinities of all organic beings may be explained. "

    If you read that chapter you will see Darwin assigns two processes to Natural Selection; "extinction of the less improved" and "divergence of character". I admit to taking some liberty in coining my own terms for them - though I think they are catchier.

    In any case you should know that your explanation above of genetic mutations is a modern addition to the "divergence of character" part of natural selection theory. Darwin may or may not have approved. Personally I agree it is plausible but I know of no evidence that supports it's action on humans resulting in modern "divergence of character". A long time has elapsed since the stone age, there should be some.

    In lieu of that my advice is the same to those wishing to improve their health: study the stone-age lifestyle to learn what environmental factors are at cause for poor health.
     
  18. Dec 12, 2004 #17

    Moonbear

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    Reality Patrol, one of my main areas of research focus is photoperiodism (in sheep). I have yet to convince NIH reviewers that humans are photoperiodic. Other than seasonal affective disorder, in which photoperiodism becomes a disorder rather than the norm, I don't know of many situations in which humans are photoperiodic. Do you have some examples? There may be some masking due to artificial lighting, but other than some old studies of the !Kung people indicating seasonal births in that population, which could also be explained by cultural pressures, there isn't any evidence that humans are photoperiodic, that I'm aware of. If you know of anything, I'd love to hear of it! Aside from SAD, all I've ever come across were a handful of articles stating susceptibility to cancer or a few other diseases was related to time of year or month of birth, but those aren't even consistent with one another once you read all of them.

    I don't even try to relate photoperiodism to humans anymore, but instead use it as a model for neuronal plasticity and reversible infertility. If there was direct evidence that humans were photoperiodic, I would really like those references.
     
  19. Dec 12, 2004 #18
    Reality_Patrol,

    As brilliant as Mr. Darwin was, I hope you understand that his book was published in 1859. I do not believe that any person studying evolution today does not understand that alot of things have changed from Mr. Darwin's original works.

    Allow me to point out another quote in his book (since we are quoting Darwin now)

    “The evidence that accidental mutilations can be inherited is at present not decisive, but the remarkable cases observed by Brown-Sequard in guinea-pigs, of the inherited effects of operations, should make us cautious in denying this tendency.”

    As you can see Mr. Darwin was toying around with the idea that mutilations could be inherited. He also believed, at least in part, that Larmarkian evolution had a minor role in evolution.

    So, maybe we should not be quoting Mr. Darwin, except in a sense of artistry.

    Nautica
     
  20. Dec 13, 2004 #19
    Very cool. First, let me share some references with you:

    1. http://jp.physoc.org/cgi/content/full/535/1/261
    2. http://www.ncbi.nlm.nih.gov/entrez/...ve&db=pubmed&dopt=Abstract&list_uids=11487664

    These are both studies that report on circadian photoreceptors in the human eye. Results are fairly conclusive: light regulates melatonin secretion via the SCN/pineal gland connection through input from a novel class of photoreceptors. That's classic photoperiodism and it was shown to occur in living human beings - very clever. As for whether it's expressed all the way to a seasonal changes in physiology the jury is still out. Many studies, each providing a piece, indicate to me it's there. Look at the Journal of Circadian Rhythms (JCR), Journal of Biological Rhythms (JBR) and Journal of Pineal Research (JPR) for starters. Some recent articles (within the last 4 years) of interest include:

    1. "On the Decline of Human Seasonlity": either the JCR or JBR,
    2. Another reports on a study was done using Austrian birth records going back before the industrial revolution. Corrections were made for social effects (holidays), results were strong seasonlity in rural Austria prior to the IR. (JBR or JCR)
    3. A very recent study on Japanese school age children and the effect of flourescent lighting on evening salivary levels of melatonin. Possible legislative action in Japan as a result was suggested. (J??)

    I'm curious too. What are your research objectives for studying photoperiodism in sheep? You mentioned neuronal plasticity and reversible fertility but it wasn't clear whether you meant in sheep or humans. I hope it was referring to humans! Overall, I'd love to hear about what your work. Please share what you can. Thanks.
     
  21. Dec 13, 2004 #20
    Agreed. Point taken. I really would appreciate, in the sense that I really am asking a question here, do you know of any evidence that supports genetic mutations leading to modern human adaptations to the artificial environment? Please share references or whatever you can. Thanks.
     
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