Salish, OK, I’ll grant you this. I keep overlooking this one group, unique amongst HG in the entire world as the only group to form permanent villages and employ chiefdoms. While they are legitimately an example of HGs with long hair they are so atypical of HGs and so simialr to agriculturalists in history, architecture and rulership as to make your comparison with ancestral HG populations spurious. Unless you want to speculate that the earliest humans were all sedentary village dwellers with rigidly defined chiefdoms then I can’t see much value in using the Salish as point of comparison. It’s hardly surpsing that they share long hair as a feature with agicultural groups given that they have so much else in common.
Crow. These people are not HGs. The group only came into existence about 200 years ago, when they split from a long established agricutural group. That split was caused largely because of the introduction of the horse allowing the exploitation of environments previously unutilisable. As such this group was dependent entirely on their herds of domesticated animals as well as trading with agricutural groups. That is not a HG society any more than the nomads of Mongolia or the Watusi of Africa.
The Mojave are by no stretch of the term HGs. They were almost entirely dependent on corn and beans for their food, supplemented with some hunting and gathering of wild foods.
Okay, I get you about the distinction between true HG and agriculturalist groups, which I missed before. But now I don’t understand how your claims about most HGs having short hair are supposed to support your earlier claim:
First you seemed to be arguing that only “the wealthiest men” ever wore long hair. Now you seem to be changing that position to argue merely that the vast majority of HG men don’t wear long hair. Are you just defining all men other than those in HG societies as “the wealthiest men”?
I will post a longer response later this evening, but here’s a quick point:
Sex hormone binding globulin is a protein that circulates in the blood. It does not just bind androgens, it binds estrogen as well. It does not sit at the hair follicle and prevent androgen activity.
No, I’m saying that amongst non-HG groups it was common for people not to get given a choice. For example the Chinese queue was not a result of choice, but rather a dictate of law. Prior to the law and following the law most men cut their hair short. The obvious question to ask is “was it even legal for men in those Indian groups to shave their heads?” I suspect the answer was “no”. There were public decency standards for hair just as there are for clothing even in western societies until not very long ago. Women with excessively short hair were actually committing a crime. I expect much the same was true of those Indian groups WRT men.
In those societies where hair lenth wasn’t prescribed by law, ie men have been given a choice, it seems that all but the wealthiest men keep their hair cut.
I don’t think that anyone has ever suggested otherwise.
This still doesn’t address the criticism that if this protein preceeded androgen sensitive beards then fertile women would exhibit no change and hence the trait is purely negative, and if it followed androgen sensitive beard devlopment then there was no selective advanatge in developing androgen sensitive beards to begin with since all men and women would be equally hairy.
Where does this come from? Most males, in the U.S at least, begin to shave in their teens, and most can grow decent, even if not full, beards by the late teens. Am I missing something?
I assume you mean that ape hair is no denser in the beard region than in other places. When you say denser, what do you mean? Hairs per cm2, or thickness/coarseness of the hair? Again, men and women have the same number of hair follicles on their faces. I bet that apes have fine villous hairs on their upper lips and cheeks that don’t show up in photos, just like modern humans do. So the hair of the beard is coarser than the hair of the scalp or forearms - so what? Its growth is under a different set of controls, so it’s not surprising that it would turn out differently. Pubic and axillary hair are coarse, and they are under the control of circulating androgens, too.
No. Again, just one process. I have no idea what the signal is that tells an ape’s cheek hair to be a terminal hair, any more than I know what the signal is that makes your scalp hair become terminal hair instead of villous hair. Let’s assume that it’s some combination of local growth factors, or sunlight, or cortisol, or insulin, or whatever. The point is that every follicle has a control mechanism in place that determines what sort of hair it will make. The control system may have multiple inputs, but it probably funnels down through one or a few common pathways at the end, as is the case for many biological systems. All cells also have receptors for testosterone, pre-existing, for other metabolic purposes. The mutation in question would have been to link the pre-existing testosterone receptors in the cheek follicle to the control path for hair differentiation. Now the default for the cheek cell is to make a villous hair unless testosterone levels rise above a certain value: not zero, but some critical threshold. This is not an impossible task; pubic hairs are villous until testosterone levels start to rise in both males and females at the start of puberty, at which point those same follicles produce terminal hairs instead. Note that pubic hair is more sensitive to androgens than facial hair is.
My definition of an androgen-sensitive beard follicle is one that makes villous hair unless it is stimulated by androgens, at which point it makes terminal hair instead.
Sex Hormone Binding Globulin (SHBG from now on) does not make circulating androgen levels go to zero in women. There is always some circulating level of androgen. If androgen production rises, or SHBG levels fall, the circulating level of androgen rises. SHBG helps to regulate circulating hormone levels by serving as a buffer of sorts. There is a complex interplay between estrogen production, androgen production, and SHBG production. There is plenty of selective pressure to have a SHBG system - it helps in the regulation of fertility, for one thing. We evolved SHBG way before we were primates.
I don’t understand your reasoning here. I’m saying that a trait developed that made some fertile females’ faces less hairy overall than all the other females.
No! The trait is that instead of automatically having terminal hair on the face in whatever the previous pattern was, some of that hair will now remain villous unless stimulated by an arbitrary level of testosterone. Fertile females can advertise their fitness by their smooth faces.
No, if she’s fertile (or at least has low circulating androgen levels - the two are linked, though) she will have facial hair of X-1. She still has the same number of hairs on her face, but more of them are villous and fewer are terminal.
If the woman has elevated androgens, her hair may end up back at X, or X+1, or Z. It really doesn’t matter whether the ‘hairy’ state matches the original state or not. Just that the non-hairy state is visibly different than the original state. Since more females are fertile than not, most females with the trait will be barefaced, not hairy. More will be helped by being able to signal fertility than will be harmed by signaling their infertility.
One last time: you can engineer the pre-existing terminal hairs on the hand to default to villous hairs unless there is a high enough level of testosterone around. The fertile females will produce smaller, paler hair on their hands, because their circulating estrogen levels are high enough to stimulate the production of enough SHBG to keep their circulating levels of androgens low enough (but not zero) to keep the hand hair from turning dark and thick. They will produce the same number of hairs, but of a different type. The prepubescent chimps of both sexes will also have hands with short, thin, pale hair, because they don’t have much androgen circulating either. In pubescent males the villous hair will differentiate into coarse, pigmented hair as androgen levels rise.
Female chimps with common endocrine problems that lead to infertility will have elevated circulating androgen levels, either due to excess production or due to low SHBG due to low estrogen levels. The fine, pale hair on the hand that they had before puberty went awry will now darken and thicken, forming terminal hair. This may or may not resemble the hair on the hand of an unmodified chimp; it doesn’t really matter. Maybe the hair looks more like human pubic hair than the silky terminal hair of a normal chimp. Both fertile and infertile chimps are showing the effects of the engineering. Mix a few engineered females into a group of normal chimps, and at first the males will mate with all females equally. Soon, however, it will fall out that mating with a barehanded female gives you a 95% chance of an heir, but mating with a hairyhanded female, either wild type or engineered, gives you only a 90% chance. Thus the trait is selected for. If you want a brute analogy, think of sickle cell trait. One copy of the mutant gene gives you relative immunity to malaria; two copies give you sickle cell disease. Yet this trait has not died out, because on a population level it saves more people in malarial areas than it kills.
And now, to bed. I’d appreciate it if others could tell me whether I’m being clear or not.
Does this really need to be spelled out? I mean that the weight/unit area is greater. Doesn’t matter whether it is longer, or thicker or with more strands/centimeter. It is strange that you apparently don’t understand that human beard hair is denser than the general body hair, and that this is not the case in apes.
And I have demonstrated that this can not have been the case.
Ancestral population has hair denisty X, which is equivalent to villous hair. One female develops a mutation that increases hair density to X+1, but only if she is infertile. If she is fertiel then the ahir density remains at X. The trait quite clearly doesn’t make make a fertiel female’s face less hairy. All it can ever do is make infertiel female’s faces more hairy. That makes no sense.
How? The gene makes some facial hair testorsterone sensitive. All females without the gene have terminal hair since their hair is not testosterone sensitive. All fertile females with the gene have terminal hair because they have levels of circulating testosterone below a critical value. Therefore fertile females with this gene look excatly like all females without it. They aren’t advertising anything because they don’t look any diferent.
Simple quetsion Brossa: Why did the first female with this gene look any different to the thousands of contemporary females who didn’t have tyhe gene? Why did she have a smooth face? Why did the other females with no gene to make facial hair testosterone sensitive develop dense hair on thair faces?
Why? Why will someone with this gene develop less hair than someone who lacks it altogether? Quite simply you need to explain why people with hair that doesn’t in any way reposnd to testosterone develop long dense hair.
You keep saying this but you haven’t explained why. Why will the hair turn dark and thick in an individual whose hair is in no way sensitive to sex hormones? What triggers the hair in these indivduals to transform from normal body hair into dark, thick beard hair? And if the hair in the ancestral individuals doesn’t become dark and thick then how are the phenotypicaly distingusihable form your female whos hair is also not dark and thick?
Yes, and the point you are ignoring is that in pubesent females who lack the gene altogether the villous hair will fail to differentiate into coarse, pigmented hair regardless of androgene levels because the hair is androgen insensitive.
As such any female carrying the gene you propose will be phenotypically indistinguishable from females who don’t carry the gene. The only time she will be distinguishable is if she is infertile. A such the trait serves solely to adevrtise alack of fitness.
I really don’t know how many ways I can say this. Which of the following statements don’t you agree with?
The ancestral trait is that all humans of all ages and all sexes have a hair of type and density X.
When the very first indivdual ever developed the gene you describe she continued to have hair of type and density X provided she is fertile.
The only time this individual (or her ancestresses) will express the trait is if she has androgen levels above a critical level.
Having androgen levels above that critical level signals infertility.
Therefore the only time this gene wil be expressed is when it signals infertility.
That makes no sense.
No. that is a baseless assertion.
Why will the fertile engineered females produce shorter, paler hair than infertile non-engineered females? Why do infertile non-engineered females produce long dark hair? And if fertile females don’t produce long dark hair then how will you phenotypically distinguish fertile engineered females form infertile non-engineered?
No, they are not. This is yet another baseless assertion.
You have not demonstarted that tehfertiel engineered chimps will eb in any way phenotypically distinct from any non-engineered female. OTOH I have demonstarted that they can not be distinguished.
No.
Only the engineered females can possibly have hairy hands. Talking about hairy handed females of the wild type is nonsense. No such phenotype can exist. the ahiry hand phenotype results entirely and exclusively form the engineered genotype.
I really don’t think you have thought this true. You can’t refer to hairy handed wild types because the wild type, by defintion, has smooth hands.
That is analogous to nothing in this therad. the sickle cell trait has positive benefit fr it possessor when it is expressed, at leats some of the time. In contrast you have yet to explain how any female who expresses the hairiness trait can possibly benefit from that expression. The only time such females benefit is when the trait isn’t expressed.
Isn’t that the case Brossa? Doesn’t expression of this gene make a female hairy? And doesn’t a lack of expression mean that she look exactly like any female without the gene? And didn’t you say that being hairy males a female less attarctive?
IOW the only time this trait ever gets expressed the possessor is evolutionarily disadvantaged. Such a gene can not survive, much less become universally possesed as you claim.
You are being perfectly clear, its just that your throey doesn’t stand up to logical examination. The gene you propose has the sole effect of transforming the normal normal juvenile-type body hair of the ancestral type into long dark hair. That is all that it does. The only way to phenotypically distinguish indivduals carrying this gene from the ancestral type not carrying it is by seeing whether they have long dark hair. there is no other phenotypic distinction between individuals with this gene and indivdiausl without it. Yet by your own admission having long dark hair for women is a disadvatage.
That makes no sense. You have posited the spread of a gene that can only ever be detrimental when expressed.
Damn, having a 5 minute edit function is really handy when it takes 5 minutes for the edit page to open.
Does this really need to be spelled out? I mean that the weight/unit area is greater. Doesn’t matter whether it is longer, or thicker or with more strands/centimeter. It is strange that you apparently don’t understand that human beard hair is denser than the general body hair, and that this is not the case in apes.
And I have demonstrated that this can not have been the case.
Ancestral population has hair density X, which is equivalent to villous hair. One female develops a mutation that increases hair density to X+1, but only if she is infertile. If she is fertile then the hair density remains at X. The trait quite clearly doesn’t make a fertile female’s face less hairy. All it can ever do is make infertile female’s faces more hairy. That makes no sense.
How? The gene makes some facial hair testosterone sensitive. All females without the gene have villous hair since their hair is not testosterone sensitive. All fertile females with the gene have villous hair because they have levels of circulating testosterone below a critical value. Therefore fertile females with this gene look exactly like all females without it. They aren’t advertising anything because they don’t look any different.
Simple quetsion Brossa: Why did the first female with this gene look any different to the thousands of contemporary females who didn’t have the gene? Why did she have a smooth face? Why did the other females with no gene to make facial hair testosterone sensitive develop dense hair on their faces?
Why? Why will someone with this gene develop less hair than someone who lacks it altogether? Quite simply you need to explain why people with hair that doesn’t in any way respond to testosterone develop long dense hair.
You keep saying this but you haven’t explained why. Why will the hair turn dark and thick in an individual whose hair is in no way sensitive to sex hormones? What triggers the hair in these individuals to transform from normal body hair into dark, thick beard hair? And if the hair in the ancestral individuals doesn’t become dark and thick then how are the phenotypicaly distingusihable from your female whose hair is also not dark and thick?
Yes, and the point you are ignoring is that in pubescent females who lack the gene altogether the villous hair will fail to differentiate into coarse, pigmented hair regardless of androgen levels because the hair is androgen insensitive.
As such any female carrying the gene you propose will be phenotypically indistinguishable from females who don’t carry the gene. The only time she will be distinguishable is if she is infertile. A such the trait serves solely to advertise a lack of fitness.
I really don’t know how many ways I can say this. Which of the following statements don’t you agree with?
The ancestral trait is that all humans of all ages and all sexes have a hair of type and density X.
When the very first individual ever developed the gene you describe she continued to have hair of type and density X provided she is fertile.
The only time this individual (or her descendants) will express the trait is if she has androgen levels above a critical level.
Having androgen levels above that critical level signals infertility.
Therefore the only time this gene will be expressed is when it signals infertility.
That makes no sense.
No. that is a baseless assertion.
Why will the fertile engineered females produce shorter, paler hair than infertile non-engineered females? Why do infertile non-engineered females produce long dark hair? And if fertile females don’t produce long dark hair then how will you phenotypically distinguish fertile engineered females form infertile non-engineered?
No, they are not. This is yet another baseless assertion.
You have not demonstrated that the fertile engineered chimps will be in any way phenotypically distinct from any non-engineered female. OTOH I have demonstrated that they can not be distinguished.
No.
Only the engineered females can possibly have hairy hands. Talking about hairy handed females of the wild type is nonsense. No such phenotype can exist. the ahiry hand phenotype results entirely and exclusively form the engineered genotype.
I really don’t think you have thought this true. You can’t refer to hairy handed wild types because the wild type, by definition, has smooth hands.
That is analogous to nothing in this thread. the sickle cell trait has positive benefit fr it possessor when it is expressed, at leats some of the time. In contrast you have yet to explain how any female who expresses the hairiness trait can possibly benefit from that expression. The only time such females benefit is when the trait isn’t expressed.
Isn’t that the case Brossa? Doesn’t expression of this gene make a female hairy? And doesn’t a lack of expression mean that she look exactly like any female without the gene? And didn’t you say that being hairy males a female less attarctive?
IOW the only time this trait ever gets expressed the possessor is evolutionarily disadvantaged. Such a gene can not survive, much less become universally possessed as you claim.
You are being perfectly clear, its just that your theory doesn’t stand up to logical examination. The gene you propose has the sole effect of transforming the normal normal juvenile-type body hair of the ancestral type into long dark hair. That is all that it does. The only way to phenotypically distinguish individuals carrying this gene from the ancestral type not carrying it is by seeing whether they have long dark hair. there is no other phenotypic distinction between individuals with this gene and indivdiauls without it. Yet by your own admission having long dark hair for women is a disadvantage.
That makes no sense. You have posited the spread of a gene that can only ever be detrimental when expressed.
One last try before I give up. I’m not going to do the line-by-line thing anymore.
You seem to be under the impression that the hair you can see on the face of an ape is villous hair, and that beard hair is terminal hair. That is not correct.
The dark hair that you see on the faces of apes is terminal hair. The dark hair on their arms, bodies, and hands is terminal hair. The hair of your scalp is terminal hair. Pubic hair is terminal hair. Beard hair is terminal hair. Eyebrows and eyelashes are terminal hair. Not every terminal hair looks the same; but if it’s thick and pigmented, it’s terminal hair.
The hair on your forehead between your eyebrows and your ‘hairline’ is villous hair. The hair on the inside of your upper arms is villous hair. The hair on the outside of your ear is villous hair. The hair on the side of your belly, away from the midline, is villous hair. All those areas ‘look’ hairless, because the hair there is fine, short, and not pigmented. According to the only quantitative researchthat I’m aware of , there are more than twice as many hair follicles on the lateral aspect of your nose than on the forehead, which has more than any of 6 other body regions tested. Not even scalp or beard hair comes in at >300 follicles per cm2. So parts of your body that are the hairiest (the lateral nose) look hairless because they are covered with villous hair. I don’t know of any quantitative studies of follicle density on the faces of great apes, but I’d bet a dollar that even the ‘hairless’ parts of a chimp’s face have villous hairs, just like your face.
Let’s go back to the genetic engineering example. The wild type chimp has TERMINAL hair on the back of its hand. The hand is visibly hairy. There are probably villous hairs there, too, closer to the knuckles, but the rest is frankly terminal hair. There is some signal pathway that tells those follicles to make terminal hair - the endpoint of which is that the dermal papilla of the follicle contains more cells and larger cells when compared to a villous hair follicle. The wild-chimp has terminal hair on the hands even as a juvenile ; both males and females have terminal hair there; it doesn’t change at puberty.
Now I engineer a chimp in which the previous signalling mechanism is co-opted such that the dermal papilla cells are stimulated to grow in size and number only when stimulated by androgens, rather than by whatever the stimulating signal was before. There are a number of ways to do this, which I won’t go into. Because I am a genius, this effect is limited to the hair on the backs of the hands. At any rate, now the hair follicles will stay smaller and produce villous hair unless androgen levels exceed a critical value.
The new chimp at birth has hands that look hairless, because the hairs are villous rather than terminal. I won’t say that they look like your hands, because some humans adults have terminal hair on the backs of their hands. But they would look like the hands of a human child, which has only villous hairs. Its wild-type cousin has visibly hairy hands at birth. The engineered males will acquire visibly hairy hands at puberty as their testosterone levels rise. Some males will never develop hairy hands, if they don’t produce the normal amounts of androgen. Most females will still have apparently hairless hands after puberty, but some will have visibly hairy hands if their testosterone levels are high. The terminal hair that develops on the engineered chimps may not look exactly like the terminal hair of the wild-type chimps.
The visible difference between wild-type and engineered chimps depends on the fact that where wild-type chimps have terminal hair by default, engineered chimps now have villous hair unless otherwise stimulated.
Now suppose I have a wild-type hominid female with some pattern of terminal and villous hair across her face. Her upper lip and chin have villous hair; her cheeks, jaw, and neck have terminal hair. A mutation occurs that affects the follicles of the cheeks, jaw, upper lip, chin, sideburns, and upper neck; basically the whole lower face, since your lips don’t have hair to begin with. The location and distribution of the mutation is an accident of history; it could have been a strip of scalp, or the upper arm of the hairy hominid. What’s important is that it overlapped an area that had a reasonably large amount of terminal hair already, so that the absence of terminal hair there would be noticeable. The fact that it overlapped an area that also had some villous hair (I’ll be generous and assume that the hominid had villous hair over the upper lip and chin) is also a historical accident.
The ancestral trait is that all hominids of all ages and sexes have some given pattern of (visible) terminal and (essentially invisible) villous hair across their faces.
When the very first individual developed this gene she displayed a different pattern of hair: more (essentially invisible) villous hair and less (visible) terminal hair across the lower face and upper neck. The total number of hairs is unchanged. What used to be terminal is now villous. The ‘average thickness’ goes way down.
She expresses the trait by having fewer terminal hairs on the face than her wild-type sisters. If she had too much testosterone, she might end up with the same distribution of terminal hairs as her sisters; she might end up having more terminal hairs if she gets a visible moustache on her upper lip where they don’t have one. She may end up with the same percentage of terminal hairs, but in different locations than the wild-type. The terminal hairs that her sons make may be thicker than the terminal hairs of the wild-type males.
Having androgen levels below that critical threshold signals a greater likelihood of fertility.
The gene is expressed whether or not she is fertile; the salient fact is that if she is fertile she ‘displays’ it by having a pattern of facial hair growth that is different than the wild-type hominids. If the terminal hairs that her sons make on their faces are thicker and darker than the hairs of their wild-type cousins, so be it. The thicker male hair is not what is selected for; it’s the thinner female hair.
Just because men shave in many societies does not mean women are not attracted to beards. If male facial hair were UNattractive to females then men wouldn’t have beards to shave in the first place. I think that relatively fleeting social norms ebb and flow, for example aristocratic society has often looked down on facial hair as brutish uncouth and uncivilized and these ideas trickled throughout much of society. Also you can imagine the economic and commercial interests of barbers and razor manufacturers promoting the clean shaven look as ideal. Conversely, there’s always a resurgence of facial hair popularity, for example, clean shaven men are often looked down upon as effeminate or unmanly.
Regardless of thsee ebbs and flows affecting the cultural influences on male attractiveness, a hypothesis would not be complete without examining the longer term genetic evolutionary factors concerning male facial hair. To this I would argue that women are attracted to men with facial hair and men who shave in equal measure. That is to say that there are women who really like facial hair on men and women who don’t, but in general women do not attach much value one way or the other because they’re more interested in OTHER qualities. Namely a man whom provides for them and their children.
Finally I believe one strong possibility for facial hair is that during our past, particularly in speaking of European tribes, we evolved as hunters in an ice aged climate. Now anyone whom has ever grown a full beard in winter knows that it acts like a ski mask keeping your face neck and ears warm. Also a mustache can protect the lips from has sun. Therfore I would consider that ancient European hunters found a distinct advantage in facial hair making them better adapted to long arduous hunting expeditions in harsh ice aged climates. This in turn made them better providers for their females which translated in evolutionary terms to the presence of male facial hair.
Did Neatherthals have beards? That was another group of ice-age European hominids.
Although modern Europeans are currently theorized to possess 2-4% Neanderthal DNA on average, that is also thought to be more related to the immune system than anything else, or maybe junk DNA. I’m not proposing it’s a Neanderthal trait, because other human lineages without that influence also have beards (although usually not as heavy).
I’m thinking maybe convergent evolution - there was something about living in ice-age Europe that made heavy facial hair on men advantageous, so it came up twice, once with the Neanderthal and once with modern humans. In which case the “natural face mask” theory might be plausible if it made men more effective hunters and enabled them to provide more food to their families, increasing the chances of their offspring reproducing themselves.
The downside to that theory is that Asiatic populations in arctic areas are not heavily bearded. Maybe heavy facial hair appeared in Europeans before people were really good at making clothing, but by the time Asiatic populations moved to a similar climate they were able to adapt with better clothing rather than needing to grow face hair.
Or maybe the Neanderthal influence did affect European hair patterns.
The only places we’re hairless are our mucous membranes and a type of skin that covers our palms, lips, and bottom of feet. Everything else has hair in varying thicknesses.
