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Thread: Is hair loss actually a step forward in evolution?

  1. #1 Is hair loss actually a step forward in evolution? 
    Forum Ph.D. Raziell's Avatar
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    Considering we have lost more and more body hair since we have found other ways to keep our bodies warm, is hair loss actually a step forward evolutionary?

    Its considered bad among us, yes. But isnt it just a reaction due to not needing it anymore?


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    Forum Cosmic Wizard paralith's Avatar
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    It depends on the cost-benefit ratio of growing hair. If growing hair is highly costly (energy-wise) and has little benefit, it will be lost. Or, if growing hair has little cost but is very detrimental, it will be lost. Otherwise, it could stick around for quite a while. My inclination is that hair on our heads is probably not very costly, nor do I see how it could be a big detriment.

    You also need to consider sexual selection. If women like men with hair better and are more likely to choose such men as mates more than they are to choose bald men, then there is still a reproductive benefit to having hair on our heads.


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  4. #3  
    Forum Ph.D. Raziell's Avatar
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    Quote Originally Posted by paralith
    It depends on the cost-benefit ratio of growing hair. If growing hair is highly costly (energy-wise) and has little benefit, it will be lost. Or, if growing hair has little cost but is very detrimental, it will be lost. Otherwise, it could stick around for quite a while. My inclination is that hair on our heads is probably not very costly, nor do I see how it could be a big detriment.

    You also need to consider sexual selection. If women like men with hair better and are more likely to choose such men as mates more than they are to choose bald men, then there is still a reproductive benefit to having hair on our heads.
    When it comes to sexual selection, how would the body know that hair was an involving factor? Or anything else for that matter. Or is every trait, if reproduction is succefull - also be deemed "worthy" so to speak?
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    Forum Cosmic Wizard paralith's Avatar
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    The body doesn't "know" anything. What happens is that the men with genes for full heads of hair have more offspring (because they were more successful at getting mates) than the men with genes for baldness. Over time, the genes for full heads of hair in the population will outnumber those for baldness, and if the selection pressure is strong enough, baldness genes could be lost forever. I'm not sure how strong the pressure is in reality, though, but it's an interesting question.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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    Forum Freshman dickies994's Avatar
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    Sexual selection probably plays a pretty large part in it, also you are looking at like evolution has a goal or a direction which it does not. Hair loss is probably incidental to our life style changes, cultural views etc.
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  7. #6 Re: Is hair loss actually a step forward in evolution? 
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Quote Originally Posted by Raziell
    Considering we have lost more and more body hair since we have found other ways to keep our bodies warm, is hair loss actually a step forward evolutionary?

    Its considered bad among us, yes. But isnt it just a reaction due to not needing it anymore?
    We exchanged it for subcutaneous fat. Like pigs, dolphins and whales.
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    Sexual selection discussions often use peafowl (peacocks) as an example. Why did the large, colorful plummages develop?

    Fisherians, named after the ideas' founder, Ronald Fisher believe sexually attractive traits are sometimes arbitrary. Initially, these attractive traits indicate health but wander off into a preference for those unrelated to strong, survival related genes.

    Amotz Zahavi opposed this, believing peacock males with prominent plummages survived in spite of the physical handicap, thus indicating virility.

    It's worth noting that male humans are more prone to baldness than females, indicating this may be related to sexual selection and parental investment. A female invests more energy in bringing young to term, forcing females to be more selective in their mates. Males are able to prolifically procreate and as such are less choosy. Reproduction just costs less for guys. As a result, female peahens are much less showy. Note that this simple description disregards other factors in parental investment such as nest/home building, the neccessity for the continual commitment from the male, ect.

    Then there is the obvious indicator of health in loss of hair, as with diseases and ailments. Similarly, peacock plummages can indicate the existence of blood parasites.
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    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Not sure we actually have less body hair.
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    On a side note, I used to raise peafowl. They are the most retarded critters ever.
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  11. #10  
    Forum Cosmic Wizard paralith's Avatar
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    Quote Originally Posted by Kukhri
    Fisherians, named after the ideas' founder, Ronald Fisher believe sexually attractive traits are sometimes arbitrary. Initially, these attractive traits indicate health but wander off into a preference for those unrelated to strong, survival related genes.
    This is rather a nit-picky note, not entirely on topic, but one that concerns me quite a bit:

    I don't like this statement for the same reason I don't like it when people call evolutionary biologists "Darwinists." It implies a system where people are blind faithful followers of their chosen paragon, and that is simply an inaccurate picture of how science works. Especially the wording you used, Kukhri, really makes it sound like some sort of cult. There are no Darwinists and there are no Fisherians - there are scientists who have assessed the hypotheses put forward by these men, assessed the evidence that is relevant to these hypotheses, and have decided to accept those hypotheses as the most likely to accurately represent reality.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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    Quote Originally Posted by paralith
    Quote Originally Posted by Kukhri
    Fisherians, named after the ideas' founder, Ronald Fisher believe sexually attractive traits are sometimes arbitrary. Initially, these attractive traits indicate health but wander off into a preference for those unrelated to strong, survival related genes.
    This is rather a nit-picky note, not entirely on topic, but one that concerns me quite a bit:

    I don't like this statement for the same reason I don't like it when people call evolutionary biologists "Darwinists." It implies a system where people are blind faithful followers of their chosen paragon, and that is simply an inaccurate picture of how science works. Especially the wording you used, Kukhri, really makes it sound like some sort of cult. There are no Darwinists and there are no Fisherians - there are scientists who have assessed the hypotheses put forward by these men, assessed the evidence that is relevant to these hypotheses, and have decided to accept those hypotheses as the most likely to accurately represent reality.
    Yeah, but that's a huge mouthful!
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    Forum Senior Kukhri's Avatar
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    Conceded. Particularly with a topic as polarized as evolution, classifying a proponent of a theory in this manner devolves the discussion into clan warfare.
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  14. #13  
    Forum Cosmic Wizard paralith's Avatar
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    Quote Originally Posted by Kukhri
    Conceded. Particularly with a topic as polarized as evolution, classifying a proponent of a theory in this manner devolves the discussion into clan warfare.
    Well put. Thank you Kukhri.
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    Body hair loss opened up the door for more sweat glands, keeping our body and more importantly our brains cooler. With a full body cooling system our brains were able to get considerably larger and help our overall advancement.

    So perhaps hair loss and brain size is loosely linked which would go in hand with intellegence among other things. Sexual selection could have played its dirty role too but it may not have been necessary as it would have been beneficial to us anyway.

    I read that when tested a majority of females prefer mens bodys that are not completely body hairless but also not too hairey so perhaps this is another indication that sexual selection played its part but again it was beneficial to us anyway, but i think nowadays television and popular culture might have more influence over what a female find sexualy attractive. It kind of adds weight to the arguement that modern people have "stopped evolving" - not that i believe that by the way
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    a couple of things to note with baldness and sexual selection:

    1) many men reproduce before they start losing their hair
    2) many women are willing to overlook physical flaws if there are compensating factors such as ability to provide or congeniality
    3) some forms of baldness can skip generations

    and then there are the crazy chicks (like me) that find bald/ing men sexy and virile.

    i have a feeling that bald guys are going to be around for quite some time to come. :-D
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  17. #16  
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Every step is forward in evolution. And in hindsight many of the steps forward turn out to steps sideways, or backwards.
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  18. #17 Re: Is hair loss actually a step forward in evolution? 
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    Quote Originally Posted by Raziell
    Considering we have lost more and more body hair since we have found other ways to keep our bodies warm, is hair loss actually a step forward evolutionary?

    Its considered bad among us, yes. But isnt it just a reaction due to not needing it anymore?
    Yes, you and I are more evolved than others of our species.

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    Quote Originally Posted by paralith
    The body doesn't "know" anything. What happens is that the men with genes for full heads of hair have more offspring (because they were more successful at getting mates) than the men with genes for baldness. Over time, the genes for full heads of hair in the population will outnumber those for baldness, and if the selection pressure is strong enough, baldness genes could be lost forever. I'm not sure how strong the pressure is in reality, though, but it's an interesting question.
    I always thought the genes for baldness came from ones mother. Wouldn't that mean that there would be no selective pressure against baldness, because the baldness wouldn't be evident in the mother? It would only be evident in her son, later in life. Or haven't I thought this through properly?
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    Forum Professor sunshinewarrior's Avatar
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    Quote Originally Posted by nlwright
    and then there are the crazy chicks (like me) that find bald/ing men sexy and virile.

    i have a feeling that bald guys are going to be around for quite some time to come. :-D
    As long as there are wonderfully discriminating women like you around (sexual selection sometimes rocks), be assured that I, and others like me, will hang around, loiter with intent, whatever is necessary, for quite some time to come...
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    Quote Originally Posted by NoLeafClover
    Body hair loss opened up the door for more sweat glands, keeping our body and more importantly our brains cooler. With a full body cooling system our brains were able to get considerably larger and help our overall advancement.

    So perhaps hair loss and brain size is loosely linked which would go in hand with intellegence among other things. Sexual selection could have played its dirty role too but it may not have been necessary as it would have been beneficial to us anyway.

    I read that when tested a majority of females prefer mens bodys that are not completely body hairless but also not too hairey so perhaps this is another indication that sexual selection played its part but again it was beneficial to us anyway, but i think nowadays television and popular culture might have more influence over what a female find sexualy attractive. It kind of adds weight to the arguement that modern people have "stopped evolving" - not that i believe that by the way
    this makes some sense
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    Forum Cosmic Wizard paralith's Avatar
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    Quote Originally Posted by lolaferocious
    Quote Originally Posted by paralith
    The body doesn't "know" anything. What happens is that the men with genes for full heads of hair have more offspring (because they were more successful at getting mates) than the men with genes for baldness. Over time, the genes for full heads of hair in the population will outnumber those for baldness, and if the selection pressure is strong enough, baldness genes could be lost forever. I'm not sure how strong the pressure is in reality, though, but it's an interesting question.
    I always thought the genes for baldness came from ones mother. Wouldn't that mean that there would be no selective pressure against baldness, because the baldness wouldn't be evident in the mother? It would only be evident in her son, later in life. Or haven't I thought this through properly?
    No, that's a very good observation, that if all you have to go by is a woman with a full head of hair, hard to guess whether or not her sons could end up bald. However, consider the way human mating works. Often enough a man will meet a woman's brothers before settling down with her, and if every last one of them is going bald, that's a pretty good sign that the sister may be carrying the baldness gene.

    However, based on what I know a lot of baldness is X-linked, which means that a balding man will certainly pass on his baldness gene to his daughters and thence to his grandsons. So a consistent preference against balding men would still reduce the prevalence of baldness in the population.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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  23. #22  
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Not so many men go bald before they reach the reproductive age.

    In fact, it is always afterwards.
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  24. #23  
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    There are also many women that simply don't have a problem with bald men. In some cases, its considered a distinguishing feature and is actually preferred (he says hopefully.)
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  25. #24  
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Isn't baldness correlated to high testosterone levels?
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  26. #25  
    Forum Senior miomaz's Avatar
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    Damn, I love my hair. It so nice to know that I probably won't even loose it! I mean, who willingly will cut himself a bald spot if he has hair? (unless you are captain picard, a monk, or some religous guy) When you start thinking baldness is sexy - or sexually preferable you are definitely too old.
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    You do know that baldness isn't just all about genes, right?

    Mycotic diseases, Iron deficiency, radiation to the scalp, Alopecia areata, Tumours and skin outgrowths, Hypothyroidism, Traction alopecia and Chemotherapy all cause baldness. So our current lifestyle may be a factor in inducing baldness. :P
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