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garytse86
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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?
stone age habbits if we want to stay healthy, how true is this statement?
garytse86 said: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?
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.Reality_Patrol said:*SNIP
Humans are photoperiodic, as are all mammals. As our modern environment severely alters the natural photoperiod our physiology is negatively impacted.
nautica said:You may have a point. We will design an experiment. Let's pretend that we are back in the IceAge. Let's take 100 people, sell our houses, sell our cars, sell our clothes, and take a plane up to the artic. Let's 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.
nautica said: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...
Nereid said: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.
nautica said:No, let's not....
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.
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
Moonbear said: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.
nautica said:Reality_Patrol,
As brilliant as Mr. Darwin was, ...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
DaveC426913 said:"Remember evolutionary preasure stops around 40 years of age."
I presume you're saying that, after 40, we are unlikely to procreate, thus not passing on traits.
Is that true in communities, say, where a whole village, including elderly, can benefit the survival of the young? Seems to me that a species who can breed children who - once they become grandparents, are wise, long-lived and healthy enough to nurture the young while the able-bodied parents are out hunting - would have an advantage.
Reality_Patrol said: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.
If there is no evidence backing a scientific theory and yet it becomes widely accepted it's called dogma. I'll go out on a limb and infer from the tone of your prior replies that you have no place in your life for religious dogma. Then why are you so adament about scientific dogma? If the genetic mutation theory is true, and if it is possible to induce to mutations in a lab in a controlled manner, then it's possible to put the theory to the test. Just keep repeating the mutations enough and eventually "natural selection: divergence of character" should emerge from the test tube. I think such an experiment would fail to provide any such proof.nautica said:What you are asking for will be almost impossible to find. Evolution takes place over hundreds of thousands of years. We have only been in the "artificial environment" for a couple of hundred. You can not expect to see evolution occur. Especially, when the artificial nature is not as strong as a selector as it would be if we are in a novel environment. No, is you want to look at the labratory settings, we have caused thousands of mutations in various organisms.
And for at least the second time I'll say again: I agree. Where should we meet?nautica said:What I can tell you in regards to humans (which I have mentioned twice in this post) is that obese people tend to have less offspring than the average person. It should be extremely obvious that if this trend continued over 1000s of years then the population eventually not have a problem with obesity. This is evolution, but you will have to check back with me in the year 102,004 for the evidence.Nautica
iansmith posted a very interesting article on https://www.physicsforums.com/showpost.php?p=258333&postcount=3 some time ago. In the time that humans have moved to and settled in artic to equatorial climes, their skin colour has adapted to the average incidence of UV.Reality_Patrol said: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.
Hmm. So, homo sap. can adapt to UV (and presumably great variations in the number of daylight hours throughout the year) in ~10-70k years, yet using fires for longer than our species has been in existence still hasn't resulted in (photo) adaptation (there's plenty of evidence that homo erectus and maybe homo habilis used fire)?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!
That is an excellent article and of course the mapping given there is far more accurate than my simplified table.Nereid said:iansmith posted a very interesting article on https://www.physicsforums.com/showpost.php?p=258333&postcount=3 some time ago. In the time that humans have moved to and settled in artic to equatorial climes, their skin colour has adapted to the average incidence of UV. How long did that take? Well, it can't have taken longer than ~50-90,000 years (when our ancestors left Africa), and may have taken as little as ~12,000 years (that's approx when the Saami moved into northern Finland).
Well my intent was to show Nautica that his experiment wasn't properly designed. Randomly selecting 100 humans from a modern population and dropping them into a pre-historic artic environment completely ignored racial/environmental matchings. He needed to include racial compositions in his sampling - then some interestings results would be obtained. But there are consequences in my opinion for photoperiodism as I'll share below.Nereid said:What has this got to do with photoperiodism?
Great point. The use of fire, and it's possible masking effect on melatonin secretion, is tricky. I should have rather written: "possibly including fire". It depends on (2) things at least: (a) the average irradiance level and duration of fire lighting provided to the population using it (which could vary a lot depending on habits/customs and availability of wood) and (b) it's spectral composition, which I assumed was blackbody, thus including blue wavelengths that stimulate the circadian photoreceptors. On second thought it seems to me that most fires I've warmed myself by are amber in appearance, indicating only a weak blue content. I'd need to look for something more definitive here.Nereid said:Hmm. So, homo sap. can adapt to UV (and presumably great variations in the number of daylight hours throughout the year) in ~10-70k years, yet using fires for longer than our species has been in existence still hasn't resulted in (photo) adaptation (there's plenty of evidence that homo erectus and maybe homo habilis used fire)??
This is only my personal speculation, as no studies or reports have been published on this, but yes there should be adaptations. Thus in our modern world some people (blondes say) have inherited highly seasonal photoperiodic attributes whereas others (blacks say) are more non-seasonal, even though the light:dark cycle regulates melatonin rhythms in all.Nereid said:Back to those Saami (and Inuit, and ...) - do they show any adaptations to the long winter nights and long summer days?
Reality_Patrol said:If there is no evidence backing a scientific theory and yet it becomes widely accepted it's called dogma. I'll go out on a limb and infer from the tone of your prior replies that you have no place in your life for religious dogma. Then why are you so adament about scientific dogma? If the genetic mutation theory is true, and if it is possible to induce to mutations in a lab in a controlled manner, then it's possible to put the theory to the test. Just keep repeating the mutations enough and eventually "natural selection: divergence of character" should emerge from the test tube. I think such an experiment would fail to provide any such proof. And for at least the second time I'll say again: I agree. Where should we meet?
And, in fact, natural selection via genetic mutation has been demonstrated in labs and observed, in human timescales and in recorded history, in the environment: http://www.talkorigins.org/faqs/mutations.htmlReality_Patrol said:If the genetic mutation theory is true, and if it is possible to induce to mutations in a lab in a controlled manner, then it's possible to put the theory to the test. Just keep repeating the mutations enough and eventually "natural selection: divergence of character" should emerge from the test tube. I think such an experiment would fail to provide any such proof.
That evolution can't be proven in a lab (as if that mattered anyway) is the prime fallacy used against it. http://www.talkorigins.org/faqs/faq-misconceptions.html#proofBacteria are easy to study. This is an advantage in evolutionary studies because we can see evolution happening in the laboratory. There is a standard experiment in which the experimenter begins with a single bacterium and let's it reproduce in a controlled environment. Since bacteria reproduce asexually all of its descendents are clones. Since reproduction is not perfect mutations happen. The experimenter can set the environment so that mutations for a particular attribute are selected. The experimenter knows both that the mutation was not present originally and, hence, when it occurred.
Reality_Patrol said:….do you know of any evidence that supports genetic mutations leading to modern human adaptations to the artificial environment?
Immunity to HIV
HIV infects a number of cell types including T-lymphocytes, macrophages, dendritic cells and neurons. AIDS occurs when lymphocytes, particularly CD4+ T cells are killed off, leaving the patient unable to fight off opportunistic infections. The HIV virus has to attach to molecules that are expressed on the surface of the T-cells. One of these molecules is called CD4 (or CD4 receptor); another is C-C chemokine receptor 5, known variously as CCR5, CCCKR5 and CKR5. Some people carry a mutant allele of the CCR5 gene that results in lack of expression of this protein on the surface of T-cells. Homozygous individuals are resistant to HIV infection and AIDS. The frequency of the mutant allele is quite high in some populations that have never been exposed to AIDS so it seems likely that there was prior selection for this allele.
There is currently no scientific evidence to support the idea that adopting Stone Age habits can improve our health. While some people may claim to have experienced positive results from mimicking the behaviors of our Stone Age ancestors, it is important to remember that our modern lifestyles and diets are vastly different from theirs. Our bodies have also evolved and adapted over time, making it difficult to accurately replicate the habits of Stone Age humans.
Some of the commonly recommended Stone Age habits for better health include eating a diet rich in fruits, vegetables, lean meats, and healthy fats, engaging in regular physical activity, and getting enough sleep. These are all generally considered to be healthy habits for anyone, regardless of whether they are attempting to replicate Stone Age behaviors or not.
As with any lifestyle change, there are potential risks involved in adopting Stone Age habits. For example, some people may find it difficult to adjust to a diet that is low in grains and dairy, which are important sources of nutrients in our modern diets. Additionally, attempting to mimic the physical activities of Stone Age humans without proper training or guidance could lead to injuries. It is always important to consult with a healthcare professional before making any significant changes to your lifestyle.
While some people may claim to have lost weight by adopting Stone Age habits, there is no scientific evidence to support this claim. Weight loss is a complex process that involves many factors, including genetics, lifestyle, and overall calorie intake. Simply mimicking Stone Age behaviors is unlikely to result in significant weight loss without making other changes to your diet and exercise habits.
While the potential health benefits of adopting Stone Age habits are still up for debate, there may be other benefits to incorporating some Stone Age practices into our modern lives. For example, engaging in activities such as foraging for food or walking barefoot can help us connect with nature and reduce stress. Additionally, following a more natural and sustainable lifestyle may have positive impacts on the environment and our overall well-being.