Aspect of Human Evolution

[pioneer]

My theory for body hair loss in humans relative to our pre-cursors, is connected to the need for more vitamin D. The human skin, when it gets tanned allows the creation of vitamin D. Maybe the diet changed, causing hair loss, which in turn, allowed a means to replace the deficiency.

 

If you compare modern males to females, males usually have some chest hair while females will usually not. Maybe the faster loss of chest hair in the females, allowed the tanning of more skin around the breasts allowing more Vit-D in their breast milk. This may have added an extra boost to the babies. Their little bodies get more used to higher vitamin-D, so when they stop breast feeding they need even more surface area for sun exposure.

 

If you look at hair loss in humans, like on the head, it form patterns. They are often referred to as pattern baldness. It is also possible, that the prehumans may have formed pattern baldness on the body. This would be a simple way to cause groups to divide and separate. Maybe the patchy semi-hairless apes learn to fit in by learning to make a body toopay, i.e., animal skin. It could have been a mother trying to protect her odd baby, covered it in an animal skin. Others soon learned to copy.

[SkepticLance]

To pioneer

Your vitamin D/sunlight theory may have some merit. However, I doubt if this is a single factor evolutionary change. As I said earlier, the main existing theories are parasite control and cooling. Your vitamin D theory may be valid, and be a third factor giving advantage to hair loss. My own feeling is that we also have to take into account the disadvantage of hair loss - that is hypothermia when the ambient temperature drops. Thus, I think the change will not happen till some technological means of keeping warm exists - whether clothing or fire.

 

As far as the differences in hair growth between male and female are concerned - most authorities seems to ascribe that to sexual attraction. A bearded man seems to have some attraction to many women, whereas women with hairy chins and chests are not attractive to males.

[foodchain]

To pioneer

Your vitamin D/sunlight theory may have some merit. However, I doubt if this is a single factor evolutionary change. As I said earlier, the main existing theories are parasite control and cooling. Your vitamin D theory may be valid, and be a third factor giving advantage to hair loss. My own feeling is that we also have to take into account the disadvantage of hair loss - that is hypothermia when the ambient temperature drops. Thus, I think the change will not happen till some technological means of keeping warm exists - whether clothing or fire.

 

As far as the differences in hair growth between male and female are concerned - most authorities seems to ascribe that to sexual attraction. A bearded man seems to have some attraction to many women, whereas women with hairy chins and chests are not attractive to males.

 

I think the studies into female male attractions with humans in regards to your facial hair one varies around reproduction actually, as in what’s attractive naturally varies attached to other variables, like FSH, just kidding.

 

I think its interesting that say hair that is kept on humans typically can have reasons easily associate with such from reality. Such as a majority of heat loss in people occurs above the shoulders.

[pioneer]

Human sexuality is hard to solidify since conditioning can be a factor, which has very little to do with natural instinct. Back in the 1950's Marylin Monroe was sort of the male's ideal image of a female, ie., full figured. A decade or two later that changed to females who were thin. These studies would have to be repeated over many generations and fads to factor out cultural condtioning before we could see what is natural.

 

One of the problems of many studies of the distant past is to project current times and attitudes onto the distance past. If a study of humans wearing animal furs was conducted in Victorian times the theory might go something like, this; they put on furs on to avoid the shame of being naked. Most ould go along with that theory, since that would have been the bias du jour.

 

The very distant humans were not us with caveman clothes. If one went to the most primative tribe on the earth and asked their theory it would probably be closer to the minset of the distant people. It would still be too advanced, but it would have less gap compared to modern humans. They may say, it is to honor the spirits of the animals that fed them. The modern human may project what the $1000 suit does for them. It would have little to do with honoring animals but with enhanced human vanity.

 

The affect of clothing is still quite primative even in modern humans. Nice clothes can indeed make one feel better or enhanced. If you analyize the clothing there is no physical properites that transfer to the body. The affect is not based on anything in physical reality. Instead the magic is based on subjective imagination and some type of induced dreamworld. One only has to go back to the fads of a previous generation. To look at that today, it looks so silly, yet at the time the dream make them strut. The dream world of the very distance people was not our dream world. Yet our dreamworld is often projected into distance times, for our times.

[SkepticLance]

To Pioneer

 

Conditioning may not have as big a part to play in sexual attraction as you think.

 

Some research was done earlier this year (reported in New Scientist - though I have lost the exact issue number). The researchers looked at the ideal woman as reported at various times in literature over the last several thousand years. They found certain commonalities across history. Slimness, for example, was a constant in beauty. So was the ideal waist to hip ratio. Ditto youth.

[Paralith]

To add to SkepticLance's statement, even the apparent changes in the "ideal" woman can potentially be explained without resorting to conditioning. In non-industrialized times, excessively thin women were probably undernourished. It was a sign of low resources, of poverty. Fuller figured women, on the other hand, were probably wealthier, had plenty of resources. A desirable characteristic, to be sure. But in modern cultures in industrialized nations, fattening fast food is some of the cheapest food around. It's relatively easy to be fat. Now the sign of wealth is the thinner woman, who can afford to buy reduced fat foods and a gym membership.

[iNow]

While the presentations of these may vary by culture or era, cues to health and fertility are the consistent themes in sexual attraction. Financial well-being, while important, tends to be secondary.

[Paralith]

While the presentations of these may vary by culture or era, cues to health and fertility are the consistent themes in sexual attraction. Financial well-being, while important, tends to be secondary.

 

Not necessarily - not if financial well-being effects your fertility. If you're wealthier you can get more and better food, better health care, you can contribute more to your offspring after they're born, etc. Resources make a big difference when it comes to female fertility. Those principles have probably become somewhat twisted these days, but that's what they're based on.

[iNow]

Not necessarily - not if financial well-being effects your fertility.

Wouldn't this just reinforce my comment that financial well-being is secondary to health and fertility? That said, I don't disagree with any of your other points.

[Paralith]

My apologies - it just seemed that you were saying that financial well-being and fertility/health weren't closely related.

[CDarwin]

For instance, neanderals have pretty large brains and a good stone tool kit, but they lack the hyoid bone necessary for complex speech.

 

I just saw this and thought "Hey, I get to correct Lucaspa!". Neanderthals had very human-like hyoid bones. This Boneclones page was the first thing that came up on Google.

 

Whether-or-not "braininess" came before spoken language depends on your definition of braininess. We only have two hominid hyoids, the Kebara Neanderthal's and the Dikika Australopithecus afarensis's, which was ape-like. Of course that says nothing as to non-spoken language, which as we all know the great apes are capable of.

 

Lucy's Baby (it had the hyoid)