5 ms·

There is an alternative hypothesis. That it's just an evolutionary accident. Possibly it's a side effect of some other factor that is significant. I mean, we g

There is an alternative hypothesis. That it's just an evolutionary accident. Possibly it's a side effect of some other factor that is significant. I mean, we get a lot of evolutionary traits because of bias through natural selection. But there's probably not much reason to lose a trait if there's no selection pressure to. It still may happen,of course. It's possible we'll all have brown eyes some time down the road. But it's not obviously because of natural selection.

vanderZwan 9y ago
Of course, there may be no strong selection pressure against it. But the odd bias for red-green distinction has been there from the earliest primates, suggesting there is a strong selection pressure in favour of specialising in red-green hue distinction. This then goes directly against having no ability to distinguish so many green and red hues. Well, unless the only genetic way to maintain this bias includes a risk of colour-blindness, but I kinda doubt that. Tangent: actually, eye colour is very strongly influenced by natural selection. Specifically, IIRC it's one of the prime examples of social and/or sexual selection pressure being stronger than other pressures, precisely because it has no other survival advantage/disadvantage associated with it otherwise. Since social success is essential for individual survival in our species, being discriminated against for ethnicity in general is a selection pressure (and before I am misunderstood: evolution is an amoral context-optimiser and Social Darwinism is one of the worst perversions of a scientific theory ever).
- c256 9y ago
  > Tangent: eye color is very strongly influenced by natural selection... Maybe, but then what’s your explanation for the prevalence of brown eyes due to natural selection?
  - vanderZwan 9y ago
    Do you realise that you are implying that sexual selection is in favour of light eyes in general? This was not what I stated. I merely talked about differentiating in- and out-groups, which is localised, meaning the homogeneity of an eye colour within an ethnicity can be explained through sexual selection. Regarding the prevalence of brown eyes, light eyes and hair are a recent and recessive mutation. That is all that is required to explain why it is localised and less common: it is limited to people who descended from the point of origin of the mutation. In this case that would be Northern Europe. http://learn.genetics.utah.edu/content/basics/patterns/ http://learn.genetics.utah.edu/content/basics/patterns/

vanderZwan 9y ago

Of course, there may be no strong selection pressure against it. But the odd bias for red-green distinction has been there from the earliest primates, suggesting there is a strong selection pressure in favour of specialising in red-green hue distinction. This then goes directly against having no ability to distinguish so many green and red hues. Well, unless the only genetic way to maintain this bias includes a risk of colour-blindness, but I kinda doubt that. Tangent: actually, eye colour is very strongly influenced by natural selection. Specifically, IIRC it's one of the prime examples of social and/or sexual selection pressure being stronger than other pressures, precisely because it has no other survival advantage/disadvantage associated with it otherwise. Since social success is essential for individual survival in our species, being discriminated against for ethnicity in general is a selection pressure (and before I am misunderstood: evolution is an amoral context-optimiser and Social Darwinism is one of the worst perversions of a scientific theory ever).

c256 9y ago
> Tangent: eye color is very strongly influenced by natural selection... Maybe, but then what’s your explanation for the prevalence of brown eyes due to natural selection?
- vanderZwan 9y ago
  Do you realise that you are implying that sexual selection is in favour of light eyes in general? This was not what I stated. I merely talked about differentiating in- and out-groups, which is localised, meaning the homogeneity of an eye colour within an ethnicity can be explained through sexual selection. Regarding the prevalence of brown eyes, light eyes and hair are a recent and recessive mutation. That is all that is required to explain why it is localised and less common: it is limited to people who descended from the point of origin of the mutation. In this case that would be Northern Europe. http://learn.genetics.utah.edu/content/basics/patterns/ http://learn.genetics.utah.edu/content/basics/patterns/