Primicerius
Mutations and human history
So obviously, lighter, thicker hair, and lighter eyes are sensible adaptations to extreme northern and frigid environments, but why did these not arise (or at least not with great frequency) in human populations in say Siberia or northern Canada? Were the "indigenous" peoples of these lands not in their environment for long enough to develop these traits or is it basically an aberration witnessed in Indo-Europeans?
Comes Domesticorum
Re: Mutations and human history
Compare with their southern brothers, Native Americans in North America have lighter skin color.
Originally Posted by Markas
Primicerius
Re: Mutations and human history
Yes, but would it be reasonable to expect them to have widespread variations in hair and eye color? Or is that a one in a million type mutation?
Comes Domesticorum
Re: Mutations and human history
Native Americans in South America actually look different than Native Americans in North America, if you ask.
Even in China there is a physical distinction between southern and northern Chinese.
Re: Mutations and human history
That's simplifying it a bit. There are several groups of Native Americans in north America that look different from each other as well, and there's established theories as well as some revisionist ones not fully accepted or complete as to why that is.
Petit Burgués
Re: Mutations and human history
Because different racial phenotypes do not always derive themselves from the weaher and geography alone. Castes, social standing and cultural trait preference might play an important role as well. It's not a world of ''individuals vs. nautre'', it's a world of ''individuals vs. society vs. nature'', quite a messy enviroment if you ask me.
For the populations of siberia to become white there would be a necessity for systematic selective breeding. Something that requires quite a large amount of time and unlike in the modern world, technologies that let natural selection do it's work.
In a world with sun-blocker, body sprays and etc. people with traits that are opposed or at least ''barely dysfunctional'' toward their enviroment are not going to be bred out.
Under the Patronage of Maximinus Thrax
Senator
Re: Mutations and human history
Europeans are just freaky aberrations, since you ask.
It’s possible we Europeans interbred with Neanderthals and they were originally the ones with funny coloured eyes and hair. They were better adapted to ice age conditions than us after all.
Or alternatively I also heard that we Europeans came through a population bottleneck of a handful of individuals, a small isolated population, a few mutant genes would go a long way in this scenario.
I remember reading somewhere that the gene for blond hair arose in Scandinavia around 11,000 years ago during the last ice age and that the gene for blue eyes arose around 10,000 years ago in the Black Sea region. They’re both recessive so they must have lead to having lots of babies in order to be so successful.
Also you’re wrong to assume that because it would be useful a particular trait is bound to evolve. Evolution has no goal. It’s all random. It only looks clever with hindsight.
Primicerius
Re: Mutations and human history
Either it will evolve or that population will suffer the consequences, right? I mean it's pretty logical that black Africans have wiry hair and high melanin content given their environment.
Primicerius
Re: Mutations and human history
Indeed this article posits that such traits were developed as the result of sexual selection: http://abcnews.go.com/Technology/sto...1#.TzmCayPBqqQ
Triggering
Re: Mutations and human history
Northern living asians are pretty close to white, southern ones are dark. Its quite possible that other cold living natives simply never had the 'lucky' mutation or did not have it in their genome due to a founder effect. Likewise I read a study once where Alaskan Inuit's have the most cold resistant hands, northern Europeans second, and black Africans last. Inuits themselves can be very light skinned.
Hair I don't see being much of a adaptation. Blond hair is believed to be a recent mutation (30k years) to last after puberty. As a child I had blond hair and blue eyes, as an adult I have dark hair and green eyes. Even Australian aborigines can have children with blond hair. Hair would be more about sexual selection than environmental adaptation. If anything darker hair makes more sense for humans being in cold climates as we don't have the type of hair that polar bears do and we don't rely on camouflage.
"When I die, I want to die peacefully in my sleep, like Fidel Castro, not screaming in terror, like his victims."
My shameful truth.
Primicerius
Re: Mutations and human history
Isn't it more a matter of not needing the melanin than camouflage? I think the sexual selection argument makes sense, but it must have been a pretty exclusive process considering the extremely recessive nature of these traits.
Triggering
Re: Mutations and human history
Its more about vitamin D vrs sun protection. Light skin is better at making vit-D and worse at protecting form skin cancer.
Sexual selection is THE most powerful selective pressure, so the speed of the spread isn't surprising. There also may have been some local bottle necks involved which help fix the gene in the first place in some communities.
"When I die, I want to die peacefully in my sleep, like Fidel Castro, not screaming in terror, like his victims."
My shameful truth.
Primicerius
Re: Mutations and human history
Right, in that type of environment you don't need as much protection from UV radiation.
Petit Burgués
Re: Mutations and human history
What does sexual selection specifically mean? factors leading to partner election or the partner election being the major factor?
Under the Patronage of Maximinus Thrax
Comes Domesticorum
Re: Mutations and human history
Probably means men prefer blond with big boobs; the brain size is secondary concern though.What does sexual selection specifically mean? factors leading to partner election or the partner election being the major factor?
Primicerius
Re: Mutations and human history
Voting with yourWhat does sexual selection specifically mean? factors leading to partner election or the partner election being the major factor?to put it crudely
Re: Mutations and human history
Ha I had straight brown hair as a kid, that went curly brownish black with puberty. Never heard of eyes changing on people though.Hair I don't see being much of a adaptation. Blond hair is believed to be a recent mutation (30k years) to last after puberty. As a child I had blond hair and blue eyes, as an adult I have dark hair and green eyes.
Primicerius
Re: Mutations and human history
I also had blonde hair when I was a little kid. I heard that we evolved that way because blonde babies and children are "more cute". If you know what I mean. They are "cuter" therefore they have higher odds of survival or becoming adopted by higher status people.
Re: Mutations and human history
Mm k' no. Blonde is easier to see.
Praepositus
Re: Mutations and human history
A lot of skin color variations have to do with sunlight and vitamin D. Lighter skin can absorb vitamin D from the sun easier, which is ideal in northern climates where you don't have much sunlight. As you near the equator, darker skin become beneficial, because there is too much sunlight, and the increased amount of melanin in the skin blocks more of the harmful rays.
Native Americans in the far north typically have darker skin than, for example, Europeans or Northern Chinese, because they eat a lot of fish that has vitamin D in it, so the sunlight issue isn't as big of a deal.
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