I know that eye color is directly related to the amount of melanin present in the front layers of the iris. But what’s the biological need behind different color?
In: 98
You tend to see more diversity in eye color in places where skin has less melanin. There is good reason for melanin reduction in skin…it enhances vitamin d production in areas without much UV light. I suspect lighter eyes are just a side effect of selection for lighter skin.
It IS biological to be suited to region and climate. Well darker skin color deflects large amount of sunlight so more suited to warmer climate just like dark eyes deflect more sunlight so they can see in the bright day. Lighter eyes absorb the sunlight because there isn’t as much just like with lighter skin to absorb as much as possible because in colder climates vitamin D is more scarce. It IS biological.
There was no need. It was simply an accident of the environment, where the genetics for lighter skin also started to affect eye colors.
Nature needed a way to distinguish prey humans, or those with blue eyes, from the warrior caste who invariably boast green/brown eyes. As with many things it is a marker of genetic health that serves to indicate suitability for mating.
Two reasons. Firstly, blue eyes less useful than brown but they’re not so detrimental that blue eyed people are handicapped. In fact someone with blue eyes might never learn that blue eyes have worse day vision and it would not change their life at all. The other reason is attractiveness. To a lot of people, blue eyes are quite pretty. If evolution was based purely utility, peacocks would’ve died out long ago. Being able to attract a mate is just as important as the strength to survive to adulthood.
Evolution doesn’t work like that. Survival of the fittest applies here. If it either improves or doesn’t hinder our ability to survive until we have kids, it continues to exist down the line. It exists only because it didn’t manage to harm our survival.
Brown eyes, like dark skin, are better suited for sunny climates, as sun protection. Light eyes, like light skin, is a mutation that survived in less sunny climates. It just means the eyes have less pigment – blue eyes aren’t actually pigmented blue, they just reflect the blue light (which is why they can look grey at times)
Latest Answers