How do you think the different 'Races' evolved?

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darkface.
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my ( laymens) understanding of evolution is that species evolve mutations adapting to their lifestyles and environment. however I was disagreeing with someone about how this actually happened with humans. Taking in respect to racial ( for want of better word) between different human groups , how did for example, white people evolve whitish/pinkish skin, Chinese and east Asian the adapted eye, African and semetic peoples the tight curly hair and Indo-European peoples straight hair. His theory was that the mutation occurred randomly, and then that was favoured in breeding groups amoungst humans and therefore spread. My contention was it was not so random, that white ppl , for example, became so due to their migration north to the arctic fringes, where they didn't need as much melanin in skin to protect from the sun. Which do you agree with?
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Algorithm69
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Mutations are always random. It is the selection that is not.
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Henry3669
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Most adaptations are explainable when one considers the environment in which a species lives. There is no absolute truth regarding the human differences in skin colour, only good guesses. The idea that the homo sapiens sapiens that migrated north to climates with less intense UV rays gradually lost melanin pigment is not an illogical one; for, as you postulate, they would not need it as much as those of us that remained closer to the equator being exposed to more intense UV rays.

With regards to the east Asian peoples and their eyelid shapes, I cannot answer. There will be a logical explanation for it, but I don't know it. It is important to note that evolution is not a perfect process and the mutations that occur among species may be totally unsuccessful or redundant.

On the whole, the reasons for the phenotypical differences between the peoples of the Earth are not objectively known, and it would be wise to admit that any suggestion is simply a suggestion.
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darkface.
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(Original post by Algorithm69)
Mutations are always random. It is the selection that is not.
that what my friend said. so it was entirely random that the white/pink skin gene popped up somewhere in Siberia/the caucuses instead of central Africa?
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darkface.
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(Original post by Henry3669)
Most adaptations are explainable when one considers the environment in which a species lives. There is no absolute truth regarding the human differences in skin colour, only good guesses. The idea that the homo sapiens sapiens that migrated north to climates with less intense UV rays gradually lost melanin pigment is not an illogical one; for, as you postulate, they would not need it as much as those of us that remained closer to the equator being exposed to more intense UV rays.

With regards to the east Asian peoples and their eyelid shapes, I cannot answer. There will be a logical explanation for it, but I don't know it. It is important to note that evolution is not a perfect process and the mutations that occur among species may be totally unsuccessful or redundant.

.
indeed but on the table is the suggestion that said mutation ie east Asian eye type became prominent purely due to breeding preference? 2 billion people all simply decided one eye type was more attractive than the other? I don't buy it
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Algorithm69
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(Original post by darkface.)
that what my friend said. so it was entirely random that the white/pink skin gene popped up somewhere in Siberia/the caucuses instead of central Africa?
Yes. The vast majority of genetic mutations have a neutral impact on the organism. Our DNA is mostly made up of junk that doesn't affect us. Only a few end up being beneficial. If the gene had popped up in Africa (maybe it did) it would have been eliminated from the gene pool for not being beneficial.
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Another
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If you take the same species of animal, put them into two different areas in breeding isolation, after thousands of years the two communities would look different. Doesn't matter whether the differences are beneficial or not to their surroundings, they would just be different.
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darkface.
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(Original post by Algorithm69)
Yes. The vast majority of genetic mutations have a neutral impact on the organism. Our DNA is mostly made up of junk that doesn't affect us. Only a few end up being beneficial. If the gene had popped up in Africa (maybe it did) it would have been eliminated from the gene pool for not being beneficial.
it sounds like a backwards version of my theory - what you are saying is that humans must have undergone a string of random colour mutations till one benefitted them ( white people in arctic). so you will proposing the idea that humans were born black, white, pink, blue, green, purple randomly at some point in history? surely its more logical to assume nature drives these mutuations for a purpose. what about the moth that mutates to precisely the colour of your bedroom wall it was born on?
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darkface.
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(Original post by Another)
If you take the same species of animal, put them into two different areas in breeding isolation, after thousands of years the two communities would look different. Doesn't matter whether the differences are beneficial or not to their surroundings, they would just be different.
they would have evolved to adapt to their different enviroments in fact- take a look at any comparable species ie sheep on flat land, goats on mountains
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Old_Simon
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My problem is that unless the "random" mutation delivers a breeding or survival advantage it is difficult to see why it began to take root in the following generations. Why should a bird which can not fly have any survival advantage ?
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darkface.
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(Original post by Old_Simon)
My problem is that unless the "random" mutation delivers a breeding or survival advantage it is difficult to see why it began to take root in the following generations. Why should a bird which can not fly have any survival advantage ?
it may have mutated to adapt to the need to borrow for its food instead, or be a swimming bird (penguin) where there were no trees to nest.
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Henry3669
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(Original post by darkface.)
indeed but on the table is the suggestion that said mutation ie east Asian eye type became prominent purely due to breeding preference? 2 billion people all simply decided one eye type was more attractive than the other? I don't buy it
I'm not particularly knowledgeable with regards to this, but it is not because of the reason you stated, hehe (although I can see why it would be suggested!!). Presumably, a random mutation occurred within the Asiatic populous which made Asian eyes (to be incredibly unscientific...) the dominant phenotype with regards to eyeshape.

When one considers that populations tend to grow exponentially, it is not difficult to see how a single person with the mutation for Asian eyes passed this on to his/her descendants and so on, until the gene for whatever eye-shape they had prior was weeded out.
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Another
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(Original post by darkface.)
they would have evolved to adapt to their different enviroments in fact- take a look at any comparable species ie sheep on flat land, goats on mountains
Then how would you explain how Indians and Chinese look completely different from each other, despite the two countries being right next to each other? The environment is the same, and yet you get that much variation.

Oh yea, and sheep and goats are two different species altogether. That example isn't a very good basis for genetic variation within homosapiens.

(Original post by darkface.)
it sounds like a backwards version of my theory - what you are saying is that humans must have undergone a string of random colour mutations till one benefitted them
Well yes, that's generally how mutations happen. Randomly. Any colour that the human gene can code for (dark brown to pale pink) can occur. Nature doesn't drive mutation, but a selection pressure. If there's no disadvantage to a gene, then it will stay.

Also, please link me to this mutating moth?
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Algorithm69
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(Original post by darkface.)
it sounds like a backwards version of my theory - what you are saying is that humans must have undergone a string of random colour mutations till one benefitted them ( white people in arctic). so you will proposing the idea that humans were born black, white, pink, blue, green, purple randomly at some point in history? surely its more logical to assume nature drives these mutuations for a purpose. what about the moth that mutates to precisely the colour of your bedroom wall it was born on?
Nature and evolution is blind. There is no mind controlling evolution. There is no purpose or end goal for evolution. Adaptions that allow a species to survive, survive.

There is a species of moth that underwent rapid evolution during the industrial revolution. The majority used to be light coloured, and could easily hide on trees and blend in. When the industrial revolution occurred, soot covered everything. Light coloured moths were now eaten easily by predators, and dark coloured moths then became the dominant colour.
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darkface.
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(Original post by Henry3669)
I'm not particularly knowledgeable with regards to this, but it is not because of the reason you stated, hehe (although I can see why it would be suggested!!). Presumably, a random mutation occurred within the Asiatic populous which made Asian eyes (to be incredibly unscientific...) the dominant phenotype with regards to eyeshape.

When one considers that populations tend to grow exponentially, it is not difficult to see how a single person with the mutation for Asian eyes passed this on to his/her descendants and so on, until the gene for whatever eye-shape they had prior was weeded out.
but if this were the case (according to the 'currently accepted' principle Algorithm was talking about) various other 'random' eye shaped would have also exponentially been passed down, because random mutations are occurring constantly- so why dont we see at least a few million square eye shapes, or hexagonal ? (or whatever) the east Asian eye type has 'conquered' the whole region, so it must be for a reason, I think to maintain that was a result of random occurances is lazy thinking. if indeed white skin randomly appearded in Africa as well as north Europe, why didn't it survive? its not like a white man in Africa would be wiped out by the sun before he had a chance to breed.
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darkface.
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(Original post by Another)
Then how would you explain how Indians and Chinese look completely different from each other, despite the two countries being right next to each other? The environment is the same, and yet you get that much variation. ?
India and china are two entirely differnt geological landscapes and climates and latitudes, for a start. But more importantly Indians are Indo-european 'races' whilst Chinese are 'mongoloid' phenotypes.

(Original post by Another)
Oh yea, and sheep and goats are two different species altogether. That example isn't a very good basis for genetic variation within homosapiens. ?
(Original post by Another)
they are related species, that evolved differently at some point, the point is still the same one regardless

Well yes, that's generally how mutations happen. Randomly. Any colour that the human gene can code for (dark brown to pale pink) can occur. Nature doesn't drive mutation, but a selection pressure. If there's no disadvantage to a gene, then it will stay. ?
there is no disadvantage to having green skin, are there any green skinned human groups around? what kind of logic is that?

(Original post by Another)
Also, please link me to this mutating moth?
mutating in terms of its genes - you do understand that moths evolve to resemble their habit don't you?
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Henry3669
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(Original post by darkface.)
but if this were the case (according to the 'currently accepted' principle Algorithm was talking about) various other 'random' eye shaped would have also exponentially been passed down, because random mutations are occurring constantly- so why dont we see at least a few million square eye shapes, or hexagonal ? (or whatever) the east Asian eye type has 'conquered' the whole region, so it must be for a reason, I think to maintain that was a result of random occurances is lazy thinking. if indeed white skin randomly appearded in Africa as well as north Europe, why didn't it survive? its not like a white man in Africa would be wiped out by the sun before he had a chance to breed.
Again, I know very little about the subject of variation with the human species, but why do you presume that other eye-shapes would have been passed down? Presumably, that eye-shape conferred a certain benefit back then (if it didn't, then it would have been weeded out itself because of its pointlessness) and no other mutation would have needed to occur.

With regards to the white man in Africa scenario, he wouldn't necessarily be wiped out, no (not by the sun at least), but black pigmented skin confers the greatest advantage to peoples living in equatorial climates. Thus, if the incredibly coincidental mutation for lighter skin happened in Africa too, then it would have been weeded out of the gene pool because it confers no benefit. Evolution is not a full random process - it knows when a mutation is redundant and when it is beneficial.

Oh, also, whilst you're right that green skin is not necessarily a disadvantage, it is also not necessarily an advantage to humans either. So, on the chance that humans undergo a random gene mutation coding for green skin, it would not necessarily last for long in the gene pool. Only the beneficial stays.
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darkface.
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(Original post by Algorithm69)
Nature and evolution is blind. There is no mind controlling evolution. There is no purpose or end goal for evolution. Adaptions that allow a species to survive, survive.

There is a species of moth that underwent rapid evolution during the industrial revolution. The majority used to be light coloured, and could easily hide on trees and blend in. When the industrial revolution occurred, soot covered everything. Light coloured moths were now eaten easily by predators, and dark coloured moths then became the dominant colour.
this it the detail of moth mutation I thought someone would bring up - what again it seems to suggest is moths must cycle through evry random colour available and get eaten till they eventually land on the colour that matches the chang in habitat? what about birds that have evolved to imitate human made sounds - there are now birds that can make the sound of chain saws and phones believe it or not - are ou maintaining that was purely a random mutation of the last 30-40 years, or is it not pssible that change was driven by human intervention in environment ( just as industrial revolution was)
I would also repeat hat I had said to henry ie - if indeed white skin randomly appeared in Africa as well as north Europe, why didn't it survive? its not like a white man in Africa would be wiped out by the sun before he had a chance to breed
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Algorithm69
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(Original post by darkface.)
this it the detail of moth mutation I thought someone would bring up - what again it seems to suggest is moths must cycle through evry random colour available and get eaten till they eventually land on the colour that matches the chang in habitat? what about birds that have evolved to imitate human made sounds - there are now birds that can make the sound of chain saws and phones believe it or not - are ou maintaining that was purely a random mutation of the last 30-40 years, or is it not pssible that change was driven by human intervention in environment ( just as industrial revolution was)
I would also repeat hat I had said to henry ie - if indeed white skin randomly appeared in Africa as well as north Europe, why didn't it survive? its not like a white man in Africa would be wiped out by the sun before he had a chance to breed
More likely that the bird simply evolved advanced vocal chords to mimic what it heard in its natural environment, and when it was introduced into modern society it already had the adaptation that allowed it to mimic chainsaws.
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POWCATTY
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with white people, it may have been a positive selection for people living closer to the poles. darker skin means more UV light is needed to produce vitamin D, so they would have had higher rate of vitamin D deficiency diseases than people with lighter skin, and this may have prevented them from migrating further out (ie rickets would mean that might not be able to walk) so surviving as long (and therefore producing as many offspring) as those with lighter skin.
with the differences in eye shape, that could just be a geographical barrier? a colony of humans could have isolated themselves? i dont actually know if there is any functional difference between the different eye shapes.
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