Evolutionary significance of the afro

[edyle]

I used the word afro which might be incorrect here; I think an afro would be when you use an afro comb and raise the hair up, but anyway what I am talking about is the extreme high-curl hair that apparently evolved in Africa.

What other areas on Earth developed such high-curl hair? What other animals developed such high-curl hair? This high-curl hair is like a recent and higher stage of evolutionary development. It forms a natural and more effective cushion than than the more common straighter hairforms which are effective against glancing impact, but perhaps not as effective against direct blunt impact.

[Falcon]

ole talk board: rofl

[edyle]

Well I suppose this topic relates to ole talk, but I am appealing more to common sense thinking, which is something that generally seems absent or curtailed nowadays.

Anyway I am going to go a little further and extend on that topic of the high-curl hair of Africa and point to a related matter: skin color. Is pigmented skin a later stage of evolution than unpigmented skin? Isn't it? How many mammals have dark skin? When you see a black dog, or a black cat, or a black chimpanzee, or somebody mentioned in an unrelated post - a black bear, if you press back the hair, do they not have white skin underneath?

Swithing gear even further, let's talk about the Chinese. Every now and again, some woman makes a baby with chinky eyes; a so-called mongoloid. Is this what we call in Trinidad a "throwback"? Maybe early man was more like a mongoloid. It happens to everybody; whether you're black white brown or yellow, everybody makes a mongoloid. And these mongoloids tend to be bigger, stronger, but dumber than the average person; kind of like Neanderthal. So maybe the early humans were more like the chinese.

Another thing, we all know that mankind is supposed to have migrated out of Africa, but you know what? That does not mean that he was black!

Putting it all together now, it is my postulation, that mankind evolved and migrated out of Africa perhaps influenced by climate change from cold ice age to hot; he looked like a big, dumb, cross-eyed Chinee. Meanwhile, evolution continued in Africa bringing forth what we see today: advanced foam structured high-curl hair (heck we could collect that from barber shops and make mattresses) and heavily pigmented skin to protect from ultraviolet sunlight. (Some would also mention tallness and ... er longness, but I'll leave those things as minor aberrations of little conviction).

[Falcon]

Against my better judgement, I will not lock this thread after reading your last post. I haven't seen this type of stuff from you before so I assume it is all sincere. Please pay attention to your common terminology.

Now, do you know how much of what you said there is contradicted by genetics, anthropology, archaeology, and just plain basic biology?

[edyle]

Against my better judgement, I will not lock this thread after reading your last post. I haven't seen this type of stuff from you before so I assume it is all sincere. Please pay attention to your common terminology.

Now, do you know how much of what you said there is contradicted by genetics, anthropology, archaeology, and just plain basic biology?

I'd like to hear the contradictions.
The first word in the name of this forum is Science. I have a degree in Physics (not biology). I have postulated an hypothesis, and I am interested in any comments and especially any contradictory evidence.

As I may have alluded too in one of my previous posts, it is common knowledge that mitochondrial dna studies have indicated that mankind migrated out of Africa; however, common default perception merely presumes that early man that migrated out of Africa resembled modern day people of Africa. I am saying that that is merely careless presumtion, and to the contrary, your common sense knowledge of: (1) Africa hair (2) pigmentation of mamallian skin, suggests otherwise; that the modern day Africa is a development over earlier man; one can say that he has these two advanced characteristics.

As for the Chinese, I think I forgot to mention one other intrigueing obsevation - chinese facial hair. Chinese tend to not have beards and moustaches.

[Sirius]

Not sure I'm following the rationale here.

If I'm not mistaken, high skin pigmentation came in order to protect the skin from the sun. This was because human beings lost their hair in order to facilitate better perspiration for heat control. Early members of the other tribes for the most part lived in higher latitudes than those who stayed in Africa - other southern latitudes such as the Americas and Australia were not settled until much later - probably too late to see the kind of significant variation as seen between those of African and Caucasian descent, for instance. Those who remained in Africa got darker while those that migrated north got fairer. Hair texture unless I am mistaken, also evolved to suit the climate - not "impact" at all as hair would be a very poor means indeed of reducing injury from a blow.

I'm also not entirely sure what you're getting at by the statement that modern day Africa is a development over earlier man. The same would be true for any other race. We have all become more upright, less hairy and with a larger mental capacity than early humans. Each race further refined their physical characteristics to better suit the environment in which they lived.

Now I'm no biologist but I have always been fascinated by evolution. The above is just based on my past knowledge and a quick skimming of search results before posting. Make no mistake though - any evolutionary variations between straight and curly hair would have emerged along the lines of thermal control; not protection against "blows". If we had evolved to take blows then we may have instead seen variations in skull shape/thickness/strength.

[skl]

what the #$%^& is someone seriously confusing children with down's Syndrome with Chinese people ?

[Falcon]

Edyle, please review the findings of the Hapmap project. That's the first bit of the evidence against your hypothesis

[edyle]

Not sure I'm following the rationale here.

If I'm not mistaken, high skin pigmentation came in order to protect the skin from the sun. This was because human beings lost their hair in order to facilitate better perspiration for heat control. Early members of the other tribes for the most part lived in higher latitudes than those who stayed in Africa - other southern latitudes such as the Americas and Australia were not settled until much later - probably too late to see the kind of significant variation as seen between those of African and Caucasian descent, for instance. Those who remained in Africa got darker while those that migrated north got fairer. Hair texture unless I am mistaken, also evolved to suit the climate - not "impact" at all as hair would be a very poor means indeed of reducing injury from a blow.

I'm also not entirely sure what you're getting at by the statement that modern day Africa is a development over earlier man. The same would be true for any other race. We have all become more upright, less hairy and with a larger mental capacity than early humans. Each race further refined their physical characteristics to better suit the environment in which they lived.

Now I'm no biologist but I have always been fascinated by evolution. The above is just based on my past knowledge and a quick skimming of search results before posting. Make no mistake though - any evolutionary variations between straight and curly hair would have emerged along the lines of thermal control; not protection against "blows". If we had evolved to take blows then we may have instead seen variations in skull shape/thickness/strength.

You make a couple important points about the evolutionary significance of hair which is actually a sort of precursor topic to what brought about my interest in the high-curl hair in Africa.

Thermal properties of hair: For many mammals, hair/fur has obvious themal significance. In the can of mankind, the thermal property of hair, I think you would agree is not as significant (although of course, a heavy head of hair in the winter is important compared to a bald head).
Aside from Themal property, hair also has lubrication property. We have hair under the armpits for example. What's the point of that? Well it does provide a lubricating effect for motion of the arm/shoulder region where the biceps area contacts the side of the chest; similarly we tend to have hair in the crotch area for lubrication between the upper thigh area for the motion of walking. What's this business about men having beards and moustaches? Well silly as it may sound the only workableish hypothesis I've come up with so far is it might have something to do with men cuffing each other in the face. I know it sounds silly, but hey, maybe when man developed language, that turned out to be the impulse to cuff somebody in the face when they said something out of place; oh, and I guess the chinese kung fu tended to aim for more important organs of the body instead of just cuffing somebody in the face so maybe that's why they don't tend to have facial hair; well its either that or from trying to eat like or dog sticking your head directly into the food and the hair protected the face from scratches.

Anyway, the point being that while hair in many mammals is significant for its Thermal properties, in humans, the Lubrication property seems to be more significant. As for the high-curl hair, the question that pops up from an evolutionary point of view is, if this new feature develops - a baby born with hair that curls very strongly back on itself, what natural advantage does this give the child that this childs offsping end up having a higher chance of survival and evetually, high-curl hair becomes predominant in later populations? My first answer is maybe it has something to do with the lubrication quality. It seems highly unlikely that the thermal property could do it. There is another answer which is to do with whether the hair can get tangled or pulled by an opponent, grabbed by a predator.

[Sirius]

Hang on Edyle. Lubrication? My reaction to that is a simple, "Say what now?" The reason hair is present in places other than the head is a sign of sexual maturity. Why do you think body hair only begins to grow during puberty, but yet children have hair on their heads long before then? Animals need to reproduce, plain and simple. Body hair is one sign to a potential mate that the body is capable of reproduction. As far as the advantages of high curl hair go you could probably look at how curly versus straight hair works in hot climates.

While there are certainly debatable topics to be spoken of in human evolution, much of what you have brought up so far is simply contrary to common knowledge.

[skl]

you working backwards edyle. people didnt start nude then develop hair. They started hairy and lost hair.

[edyle]

you working backwards edyle. people didnt start nude then develop hair. They started hairy and lost hair.

Hair was lost during evolution of man, but the hair that remained, adapted and evolved.

[edyle]

Here's an interesting piece from a book:

http://ia600302.us.archive.org/7/items/raceprejudice00finouoft/raceprejudice00finouoft.pdf

From: Race Prejudice
pg 104/105


III. The Hair
The hair is in direct correlation with the colour of the
skin. It is thus that with the dark skin of the Negro
is seen their woolly hair, very short and frizzled. Bory de
Saint Vincent thinks there are two principal qualities which
distinguish human hair. In the case of some it is smooth
(leiotrichous), with others it is woolly (ulotrichous). When the
hair appears rectilinear in all its length, we consider it smooth.
But when curved and like little ringlets interlacing each other
like tufts of wool, we call it frizzled.
Nevertheless the hair, like the colour, varies from shade to
shade. An attentive observer could even establish a sort of
harmonious gradation which would comprise all varieties and
render their successive transformations evident. According to
Brown, the stem of a hair cut transversely allows us to
recognise human races. In the Negro it is like an elongated

ellipse, in the Red Skin like a circle, and in the Anglo-Saxon it
is a form between these two.
Primer Bey, in starting from the thickness of the hair's stem,
points out three principal categories : hair with very narrow
stem like the flat hair of the Bushmen or ordinary Negro, the
intermediary hair of white races, and finally the hard hair,
thick and round, belonging to Mongols, Chinese, Americans
and Malays.

The gradation from flattened or elliptical hair to round hair cross-section is very interesting. It should be very interesting to see whether the other primates tend to have elliptical or round hair cross-sections.

[skl]

Hair was lost during evolution of man, but the hair that remained, adapted and evolved.

ahhh biggest problem people have in understanding evolution.

the hair didnt adapt and evolve.

humans that had underarm hair survived and bred and outbred those that were hairy all over.

[edyle]

Edyle, please review the findings of the Hapmap project. That's the first bit of the evidence against your hypothesis

Haven't found any contradictions yet. Have you?

[edyle]

ahhh biggest problem people have in understanding evolution.

the hair didnt adapt and evolve.

humans that had underarm hair survived and bred and outbred those that were hairy all over.

ok fine, the hair did not adapt; the
humans that had a slightly different type of hair survived and bred and outbred those that had the older kind of hair.

[Falcon]

Edyle, did you find thepart about maximum diversity and the founder effects?

[edyle]

Edyle, did you find thepart about maximum diversity and the founder effects?

No not yet; looking.
Had not found anything resembling findings either.


The International HapMap Project is an organization that aims to develop a haplotype map (HapMap) of the human genome, which will describe the common patterns of human genetic variation. The HapMap is expected to be a key resource for researchers to find genetic variants affecting health, disease and responses to drugs and environmental factors. The information produced by the project is made freely available to researchers around the world.

[edyle]

http://news.nationalgeographic.com/news/2005/06/0624_050624_spencerwells_2.html


In his book, The Journey of Man: A Genetic Odyssey, Wells describes the exodus from Africa that began around 60,000 years ago, and the path we took to populate the world.

Following the southern coastline of Asia, the first early travelers crossed about 250 kilometers [155 miles] of sea, and colonized Australia by around 50,000 years ago. The Aborigines of Australia, Wells says, are the descendants of the first wave of migration out of Africa.

A second wave left Africa around 45,000 years ago and settled in the Middle East, with smaller groups going off to India, northern China, and southern China. As the glaciers of the Ice Age began to retreat around 40,000 years ago and temperatures warmed up, humans moved into Central Asia and multiplied quickly.

Small groups left Central Asia around 35,000 years ago for Europe. Around 20,000 years ago, another small group of Central Asians moved farther north, into Siberia and the Arctic Circle.

So you've got 1 wave out of Africa going off to Australia; a second wave going off to Asia; and a third wave to Sibera and the eskimos. The Aborigines, the Chinese and the Eskimos don't have high-curl afro hair. On the face of it, as is my original statement, there is no reason to believe that early man had high-curl afro hair, and to the contrary high-curl afro hair seems to be a later development;

I'm still looking for any contradictory evidence, for example from teh Hapmap data.

[Falcon]

Edyle, the greatest diversity is found in African populations. The European populations have much fewer polymorphisms in their genomes. That disproved your enhanced evolution theory.

The Afro isn't a hard hat, just to say where I stand on that issue.

Hair isn't a lubricant; it is an insulator and an indicator of hormonal status. Your theories are so far removed from basic biology that it is almost ole talk.

[edyle]

http://en.wikipedia.org/wiki/Hair


Human "hairlessness"

[Ambox question.svg
This article or section may contain previously unpublished synthesis of published material that conveys ideas not attributable to the original sources. See the talk page for details. (November 2010)]

Human body hair is barely visible as it is thinner, shorter, and more translucent than the hair of other mammals. Humans are part of a trend toward sparser hair in larger animals (fewer follicles per square inch of exposed skin). There are several African mammals that have very sparse fur, including the elephant and the hippopotamus, both at the upper end of this trend. The density of human hair follicles on the skin is about the average for an animal of equivalent size.[18] It still is not clear why so much of human hair is short, under-pigmented vellus hair, rather than terminal hair, and the effect of testosterone on the hair follicles in both human and other mammalian species. Because most human hair is less apparent vellus hair, this gives the appearance of being hairless, especially in females.

Most mammals have light skin that is covered by fur, and biologists believe that early human ancestors started out this way also. Dark skin probably evolved after humans lost their body fur, because the naked skin was vulnerable to the strong UV radiation as would be experienced in Africa. Therefore, evidence of when human skin darkened has been used to date the loss of human body hair, assuming that the dark skin was needed after the fur was gone.

Dr. Alan R. Rogers, an evolutionary geneticist at the University of Utah, used mutations in the MC1R gene to estimate when human skin darkened. He said early humans may have gone through several genetic "clean sweeps" with light-skinned individuals dying off and dark-skinned individuals surviving. He estimates the last of these clean sweeps took place 1.2 million years ago.[19] Therefore, apparent bareness in humans, likely has existed at least since that time. Later when humans began to live in more northerly latitudes, however, light skin became an advantage for the absorption of vitamin D and the recessive gene began to become more prevalent in those populations.

[Falcon]

I hope you realise that the quoted material supports humans adapting to suit their environment.

[skl]

oh boy

ok first Journey of Man by Wells is unfortunately outdated. it was publised in 2002. In 2009


The Human Genome Organisation's (HUGO) Pan-Asian SNP Consortium carried out a study of almost 2,000 people across the continent.

Their findings support the hypothesis that Asia was populated primarily through a single migration event from the south............. answered a question about the origin of Asia's population. It showed that the continent was likely populated primarily through a single migration event from the south.

Previously, there has been some debate about whether Asia was populated in two waves - one to South East Asia, and a later one to central and north-east Asia, or whether only a single migration occurred.
http://news.bbc.co.uk/2/hi/8406506.stm

It is now believed that there were only two waves. One which left africa headed to SE Asia and then moved northwards.

The second wave left africa reached india , turned around and headed to Europe.




Also Please note

http://en.wikipedia.org/wiki/Toba_catastrophe_theory

Recent analyses of mitochondrial DNA have set the estimate for the major migration from Africa from 60,000–70,000 years ago,[46] around 10–20,000 years earlier than previously thought, and in line with dating of the Toba eruption to around 66,000–76,000 years ago. During the subsequent tens of thousands of years, the descendants of these migrants populated Australia, East Asia, Europe, and finally the Americas.


According to the supporters of the genetic bottleneck theory, between 50,000 and 100,000 years ago, human population suffered a severe population decrease—only 3,000 to 10,000 individuals survived—followed eventually by rapid population increase, innovation, progress and migration.[26] Several geneticists, including Lynn Jorde and Henry Harpending have proposed that the human race was reduced to approximately five to ten thousand people.[27] Genetic evidence suggests that all humans alive today, despite apparent variety, are descended from a very small population, perhaps between 1,000 to 10,000 breeding pairs about 70,000 years ago.[28]


we are not talking about millions of people here. what is being suggested is that the human population consisted less than 10,000 people in africa. some of these who were apparently straight haired ended up leaving Africa and migrating elswhere.

Evolutionarily speaking, just because a trait exists doesn't mean there has to be a reason for it. There just has to be a lack of a reason against it.

[edyle]

I hope you realise that the quoted material supports humans adapting to suit their environment.

I'm perfectly aware of what the quoted material says. Species adapting to the environment through natural selection is exactly what the thread is about. Specifically, the question mark is the high curl hair of Africa. Did early man have high curl hair? It seems unlikely to me. So when and curiously, why did high curl hair develop? A related question, assuming that it developed relatively late - what advantage did high curl hair provide? Was it as Sirius suggested something to do with thermal properties? Or could it be as I've suggested, something less obvious than thermal property.

[skl]

I'm perfectly aware of what the quoted material says. Species adapting to the environment through natural selection is exactly what the thread is about. Specifically, the question mark is the high curl hair of Africa. Did early man have high curl hair? It seems unlikely to me. So when and curiously, why did high curl hair develop? A related question, assuming that it developed relatively late - what advantage did high curl hair provide? Was it as Sirius suggested something to do with thermal properties? Or could it be as I've suggested, something less obvious than thermal property.

why does it seem unlikely to you ? you realize you are basing this entire thread on that supposition.

[edyle]

oh boy

ok first Journey of Man by Wells is unfortunately outdated. it was publised in 2002. In 2009


http://news.bbc.co.uk/2/hi/8406506.stm

It is now believed that there were only two waves. One which left africa headed to SE Asia and then moved northwards.

The second wave left africa reached india , turned around and headed to Europe.




Also Please note

http://en.wikipedia.org/wiki/Toba_catastrophe_theory





we are not talking about millions of people here. what is being suggested is that the human population consisted less than 10,000 people in africa. some of these who were apparently straight haired ended up leaving Africa and migrating elswhere.

Evolutionarily speaking, just because a trait exists doesn't mean there has to be a reason for it. There just has to be a lack of a reason against it.

Evolutionarily speaking, do you find it curious that there seems to be no straight haired people indigenious to central and southern Africa? There may be a lack of a reason against high-curl hair, but why would all the straight haired populations disappear?

[skl]

I'm perfectly aware of what the quoted material says. Species adapting to the environment through natural selection is exactly what the thread is about. Specifically, the question mark is the high curl hair of Africa. Did early man have high curl hair? It seems unlikely to me. So when and curiously, why did high curl hair develop? A related question, assuming that it developed relatively late - what advantage did high curl hair provide? Was it as Sirius suggested something to do with thermal properties? Or could it be as I've suggested, something less obvious than thermal property.

why does it seem unlikely to you ? you realize you are basing this entire thread on that supposition.

[edyle]

why does it seem unlikely to you ? you realize you are basing this entire thread on that supposition.

Thank you for recognising the core point!

Why does it seem unlikely to me that early man had high curl hair?

High curl hair does not seem to occur in other mammals. The closest supposedly is sheep. The other primates (mankind being a primate) do not seem to have high-curl hair.
We don't find it among eskimos; or the tribes of South America, or New Guinea.

Maybe early man did have high-curl hair, but the obvious evidence suggests that it was a later development.

[Sirius]

Okay, I'm going to say something. I haven't looked up any evidence but it seems to make sense to me and hopefully will be some food for thought in this discussion.

Is it not possible that the individuals who survived in Africa were probably an intermediate "race" if you will? Darkish skin but not very dark, and curly hair but not yet tightly coiled and springy? Perhaps those that remained in hot climates became darker and their hair became today's high curl texture seen in those of African descent, while those that migrated to the cooler climates grew fairer with straightening hair? It might be noteworthy that the Australian aborigines (who remained in warm climates) tend toward curly hair, though not as much so as those from Africa.

In any event, I have not seen anything of credence for the retaining of hair on human heads and the variations in hair texture beyond the reason of thermal control. Springy hair tends to be less of a heat trap than straight hair.

[edyle]

Okay, I'm going to say something. I haven't looked up any evidence but it seems to make sense to me and hopefully will be some food for thought in this discussion.

Is it not possible that the individuals who survived in Africa were probably an intermediate "race" if you will? Darkish skin but not very dark, and curly hair but not yet tightly coiled and springy? Perhaps those that remained in hot climates became darker and their hair became today's high curl texture seen in those of African descent, while those that migrated to the cooler climates grew fairer with straightening hair? It might be noteworthy that the Australian aborigines (who remained in warm climates) tend toward curly hair, though not as much so as those from Africa.

In any event, I have not seen anything of credence for the retaining of hair on human heads and the variations in hair texture beyond the reason of thermal control. Springy hair tends to be less of a heat trap than straight hair.

Yes I think that is certainly possible and even reasonable. And even reading the sentence on intermediate "race" brought to my mind the matter of the Australian aborigines before you mentioned it literally. As for the thermal characterisics of the high-curl hair, I imagine it would have something after all perhaps it tends to trap air better sort of like a styrofoam cap, although I imagine this would be advantageous in a warm climate.

Maybe there were primates prior to humanoids that had curly hair? I don't think there are any now.

[Sirius]

Maybe there were primates prior to humanoids that had curly hair? I don't think there are any now.

I would doubt it. One characteristic of human hair different to our other primate cousins is how long ours can get. While they maintained a shorter but straight covering of hair over the entire body, as upright walkers we got it only on our heads and capable of growing much longer. It's not so much the straightness of the hair that makes it a heat trap - it's the length said straight hair can grow to.

[trini123]

Afro=protection from sun
Chinese eyes=protection from light
Dark skin=protection from sun

[edyle]

I would doubt it. One characteristic of human hair different to our other primate cousins is how long ours can get. While they maintained a shorter but straight covering of hair over the entire body, as upright walkers we got it only on our heads and capable of growing much longer. It's not so much the straightness of the hair that makes it a heat trap - it's the length said straight hair can grow to.

Now THERE is a good point suggesting the opposite of what I was postulating; the issue of length of human head hair in a way. Maybe high curl hair developed on prehuman and early humans as an intermediate stage before long hair evolved in humans. At least pictorially it would look like an intermediate stage, plus, even if the actual length of the hair my grow long if stretched out, it would be short on the profile and not hamper visions etc.

[edyle]

Afro=protection from sun
Chinese eyes=protection from light
Dark skin=protection from sun

I'm trying to imagine a black chinee with an afro.

[trini123]

Evolutionarily speaking, do you find it curious that there seems to be no straight haired people indigenious to central and southern Africa? There may be a lack of a reason against high-curl hair, but why would all the straight haired populations disappear?


I think people evolved after leaving Africa to suit the new climate. We all originated from a group of probably black people(curly hair included). Many people may not like this especially if they associate with the KKK but that is reality.

[edyle]

I think people evolved after leaving Africa to suit the new climate. We all originated from a group of probably black people(curly hair included). Many people may not like this especially if they associate with the KKK but that is reality.

And I'm saying the evidence is that mankind probably started out with straight hair and unpigmented skin just like most mammals, and these traits of pigmented skin and high curl hair evolved later.

How many blackskined or high-curl-hair animals do you know? Any at all? Why would a new specie (human) develop, and suddenly ALSO have 2 distinguishing traits (pigmented skin and high-curl hair), then devolve backwards to the norm of unpigmented skin and simple straight, round-cross-sectioned hairs?

[Sirius]

And I'm saying the evidence is that mankind probably started out with straight hair and unpigmented skin just like most mammals, and these traits of pigmented skin and high curl hair evolved later.

How many blackskined or high-curl-hair animals do you know? Any at all? Why would a new specie (human) develop, and suddenly ALSO have 2 distinguishing traits (pigmented skin and high-curl hair), then devolve backwards to the norm of unpigmented skin and simple straight, round-cross-sectioned hairs?

How do we know that humans were already 100% high curl hair and dark skin when they moved out of Africa? Even if we throw out the "intermediary" idea I posted before and assume that we were totally dark with high-curl hair when moving out then it's a simple concept that under the temperate conditions of the north the genes responsible for those traits would go into dormancy.

There's another bit of information to consider. If it is that the human population was reduced drastically before migration, then it would mean that very small numbers spread around the various regions of the world. With such small numbers it won't be very difficult for simple societal preferences in mating choices to determine the distinctive traits we see in modern-day races of each region.

At the end of the day, these questions will be very difficult to answer unless we start finding viable DNA samples.

[kemist]

Anyway I am going to go a little further and extend on that topic of the high-curl hair of Africa and point to a related matter: skin color. Is pigmented skin a later stage of evolution than unpigmented skin? Isn't it? How many mammals have dark skin? When you see a black dog, or a black cat, or a black chimpanzee, or somebody mentioned in an unrelated post - a black bear, if you press back the hair, do they not have white skin underneath?



do we know whether these furry mammals evolved to having 'white skin' or skin without pigment?

[edyle]

do we know whether these furry mammals evolved to having 'white skin' or skin without pigment?

In the absence of other evidence, what does your own common sense guess logically tell you?

[edyle]

Okay, I'm going to say something. I haven't looked up any evidence but it seems to make sense to me and hopefully will be some food for thought in this discussion.

Is it not possible that the individuals who survived in Africa were probably an intermediate "race" if you will? Darkish skin but not very dark, and curly hair but not yet tightly coiled and springy? Perhaps those that remained in hot climates became darker and their hair became today's high curl texture seen in those of African descent, while those that migrated to the cooler climates grew fairer with straightening hair? It might be noteworthy that the Australian aborigines (who remained in warm climates) tend toward curly hair, though not as much so as those from Africa.

In any event, I have not seen anything of credence for the retaining of hair on human heads and the variations in hair texture beyond the reason of thermal control. Springy hair tends to be less of a heat trap than straight hair.

(Putting aside the hair for a moment and just looking at the pigmented skin).;
I think there might be something to this suggestion when one looks at the hominid/homo listing below from wikipedia.
I would make sense that in the evolution of the species, during a warming trend in the climate, it became advantageous to be hairless because it was warm anyway. The skin would have been unpigmented at first like the ancentors, but once hairlessless was prevalent, it was also advantageous to be pigmented in the warm sunny climate; thereafter the genepool was sufficient for the species to survive and adapt to warmer and cooler environments.


Subfamily Homininae (or Hominidae)

* Homo – immediate ancestors of modern humans
o Homo habilis†
o Homo rudolfensis†
o Homo ergaster†
o Homo georgicus†
o Homo erectus†
o Homo cepranensis†
o Homo antecessor†
o Homo heidelbergensis†
o Homo rhodesiensis†
o Homo neanderthalensis†
o Homo sapiens
+ Homo sapiens idaltu†
+ Archaic Homo sapiens (Cro-magnon)†
o Homo floresiensis†
* Oreopithecus†(hominid status disputed)
* Paranthropus†
* Australopithecus†
* Sahelanthropus†(hominid status highly problematic)
* Orrorin†
* Ardipithecus†
* Kenyanthropus†

[kemist]

Well we do know that mammals evolved from fish. So skins must have evolved too. But i havent seen anything on the pigmentation of skins of the first mammal-like creatures. So there are 2 scenarios:

1. mammals evolved fur for temperature control, and since this is also an efficient barrier against light, furry animals do not need dark pigmentation.
2. these animals started off with dark pigmentation, then grew fur after which they didnt need the pigment anymore and so lost it

i doubt they started off with pigmentation and then lost it, because i would think that species don't evolve by losing redundant features, but by gaining features that are needed. So in going from fish to mammal-like reptiles to the first 'pure' mammal, the latter may have started off without dark pigmentation and gained fur.

When looking at animals, perhaps the key is within that gap between evolution from mammal-like reptiles to 'pure' mammals.

[edyle]

Well we do know that mammals evolved from fish. So skins must have evolved too. But i havent seen anything on the pigmentation of skins of the first mammal-like creatures. So there are 2 scenarios:

1. mammals evolved fur for temperature control, and since this is also an efficient barrier against light, furry animals do not need dark pigmentation.
2. these animals started off with dark pigmentation, then grew fur after which they didnt need the pigment anymore and so lost it

i doubt they started off with pigmentation and then lost it, because i would think that species don't evolve by losing redundant features, but by gaining features that are needed. So in going from fish to mammal-like reptiles to the first 'pure' mammal, the latter may have started off without dark pigmentation and gained fur.

When looking at animals, perhaps the key is within that gap between evolution from mammal-like reptiles to 'pure' mammals.

Exactamundo