why white people have blue, green and brown eyes while black and asian people tend to have only brown eyes?

Answer 1

Blue eyes: The most sensitive eye color.
Green eyes: Second most sensitive.
Brown: Least sensitive eye color.

-Depending on where our ancesters moved to- whever the most sun was- we have darker or lighter eyes. (Similar to the reason why we have different skin colors.)

Answer 2

Long story short, it's a side effect of the overall lessening of skin pigment.

Longer story, the pigment lightening stared as a response to a dietary shift caused by the introduction of farming in the late neolithic. Hunter gatherers got enough nutrients from their diet to keep the Mediterranean coloration. The farmer's diet of grains didn't have enough vitamin D, so the olive skinned northern Europeans were affected with developmental deficits that stunted bone growth. The precursors were there, but they needed a reasonably sunny environment to be useful, which northern Europe doesn't have.

The selective factor was an increase in the number of women and infants who died in childbirth due to the reduced size of adult women's hips. The solution was a mutation that radically lowered overall pigmentation, and a few others that altered the size and shape of northern Europeans hips. Side effect, genes for non brown eye colors became more common.

Answer 3

Melanin pigment (found in hair skin and iris of eye) comes in multiple shades of yellow, green, brown and VERY dark brown, almost black. It is a complex set of genetic principles for eye-hair and skin color, some are using POLYGENIC inheritence, like skin color.

And it is not true about "racial eye colors" that you stated. While the majority of each of those cultures may have these colors, there are all colors of eyes possible if the recessive genes become blended in those gene pools. However many blacks who have the lighter eyes may have had children with a caucasian who had these more recessive genes.

Answer 4

It's because of genetic traits. White people have recessive traits, that's why they get brown, blue, and green eyes. The dominant gene is for brown eyes and dark skin.

Asians and Africans have the dominant genes.

Answer 5

its because of how much melanin that you have in your skin, like how dark the color of your skin is, if you are white you will have blue/green eyes, if you mexican, or black you will have brown or black eyes, it's just genetics, and that is how it is

Answer 6

because white people need lighter eyes to camaflouge themselves from places where it's mostly white, like their skin and snow. vice versa for people with darker colured eyes. they were more succesful when it came to hunting during these cavemen times.

Answer 7

this isn't true at all,i have seen native American and black people,both,with green eyes.