why are people with blue eyes more sensitive to sunlight?
459187
Blue eyes, Blonde hair and Fair skin are all traits of low melanin or keratin which are pigmentation substances in the skin and hair.
989150
It's because of evolution, yes. When people are exposed to higher levels of ultraviolet light, extra melanin in the skin will reduce the risk of skin cancer and will therefore be a survival advantage, so natural selection will favour dark-skinned individuals with the genes for producing extra melanin. Individuals with these genes are more likely to survive to childbearing age and will be more likely to pass on the genes. In colder climates, extra melanin does not affect the chances of survival as much so it is not selected for, though characteristics such as extra body hair and fat may be selected for.
661379
The blue sky is caused by the light from the sun travelling through the upper atmosphere and passing through particles, which scatter the blue part of the spectrum quite well. The other parts of the spectrum are still scattered, but less efficiently. So you see a 'blue' sky because that's the part of the light spectrum being directed towards you.\nYou could look up the Rayleigh Effect for more indepth info.
773156
There have been THREE sets of genes identified which contribute to eye colour.  The reason why green eyes are so rare is that the genes the produce green eyes are themselves rare.\n\nOne set of genes has a brown and blue version, one set has a green and a blue version, and one set controls shading in brown eyes.  The best explanatory theory right now actually suggests that brown is dominant to all other colours (so someone with a mix of genes is probably brown-eyed), green is dominant to blue (so a green-eyed parent and a blue-eyed one will have some green-eyed kids), and blue is completely recessive.  The reason blue is more common than green as an eye colour is that there are just so few green-eyed genes in the population.\n\nIt bears mention that this theory fails to explain many oddities of eye colour, so there are probably several other genes that are involved but haven't been located yet.  (That's what makes biology exciting, if you ask me!)\n\nNor is there any reason to believe that green eyes are going to 'disappear' from future generations.  Unless some kind of selective force acts on genes, they are just as frequent in each generation, though they may become more spread out.  So if 1% of the population has a green-eyed gene in one generation, the same percent is likely to have it in every following generation, barring some kind of accident, selective pressure, or the like.
1156736
Blue eyes: The most sensitive eye color. \nGreen eyes: Second most sensitive. \nBrown: Least sensitive eye color. \n\n-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.)
1168385
Because of their skin color. I know that everyone needs to put on some sun screen. Just because your skin is dark doesn't mean you are protected form UV rays.
191878
The sky is blue because of the ozone layer, which is blue. The ozone layer is blue because (have you ever tried to shine light through a triangular pyramind (glass)?) It filters everything but blue color...why? I don't know. Uh...I'm not sure, probably because they want to know more about female sex organs because girls have 2 and we have 1 ugly sex organ that's not exactly as attractive as girls. Not that I'm a pervert...only nerds are.
406219
its mostly in the way you perceive that day but at the same time sunlight exposure increases seratonin production in the brain thereby putting you in a better mood.
1121858
Light infusion from the sky gives the blue appearance that most observe
293753
Your friend is correct. I just studied this in school. Dark hair always dominates light hair. And the allele for green eyes overpowers the allele for blue eyes.
40716
I disagree with the one said blue eyes are dominant. Actually the gene of blue eyes is resessive. So if either one parents or grandparents have the gene of brown eyes, their offspring can more chances to get brown eyes than blue. Of couse, blue or brown eyes really depends on the genotype of the parents, not the phynotype. So if and only if both parents have blue eyes, they offspring have 100% chances to get pure blue eyes gene. \n\nSO if your eye color is brown, and your children are blue, that means that you have a blue eye gene, but because it is recessive, thus the phynotype of your eye color is brown. Your children would have 1/2 chance to get either blue or brown eye color in this situation.\n\nThe following link talks about the eye color in detail.
144874
A major cause of light sensitivity in people is just that they don't have a lot of pigment in their eyes.  If you have fair skin/hair and light irises, this could easily be the cause.  If this is something that you just started experiencing, you should know that there are many diseases/infections that have photosensitivity as a symptom.  If that's the case for you, make an appointment with your eye doctor.
919857
The people who come from Mongolian Heritage have evolved to cope with their environment. The "squinty" eyes you are referring to serve them well when the Yellow River dust storms blow and the glare of the sun would make big blue eyes blind.\nAs for the hair, yes, it is always dark but not always fine. That was for a survival purpose too. Some Chinese people have very thick hair. Black is the dominant colour because it is stronger than other colours, so even in  international marriages, the children will have dark hair. Some toddlers will be seen with naturally fair hair though, but it darkens as they get older.\nThings evolve gradually, but sometimes also quite quickly ... a lot of Chinese have big and wide-open eyes these days. It used to be put down to cosmetic surgery, but some are born with such eyes naturally; obviously a sign of evolution.\nBy the way, it might surprise you to hear that not so long ago people with blue eyes were thought to be blind. A serious misconception but due to ignorance. \nIn every ethnic group there are diversities. Eyes are often the centre of focus because they are the centre of attraction. But if the eye reveals the soul of that person, it doesn't matter what shape or size it is.
14578
because the atmosphere absorbs most of the other colors of the spectrum so all you see is mainly blue.
702252
I think its 3 to one since blue is a recessive trait compaired to brown or any other darker eye color since eye color is a mix of pigment and pattern.
66169
The sun's rays hit the Earth's atmosphere, where the light is scattered by nitrogen and oxygen molecules in the air. The blue wavelength of this light is affected more than the red and green wavelengths, causing the surrounding air to appear blue. At sunset, the sun's light passes farther through the atmosphere, deflecting and decreasing the blue in the air. Scattering by dust particles and pollution in the air causes the sunset to appear red.
558551
hmm...I have "hazel" eyes and they do change color from green to blue to a mixture of both, etc.  I have never associated it with the weather.  If i had to guess I would say that perhaps due to atmospheric pressure the rods and cones in the persons eyes could possibly change shape slightly and therefore relect light in a slightly different frequency.