what is the purpose of eye color?

A

amark317

game developer-in-training
Registered Senior Member
I have been wondering this for a long time, and am asking you this.
what is the evolutionary purpose of eye color, and why do so many exist? is it at all related to survival?
 
amark317 said:
I have been wondering this for a long time, and am asking you this.
what is the evolutionary purpose of eye color, and why do so many exist? is it at all related to survival?
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You mean "Why is the iris colored at all?" or "Why do humans have different eycolors?" ?
 
I have no idea, but it's really interesting. Is it a sign of anything related to our body?
 
I couldn't find anything on the 'purpose'.

Wiki says: http://en.wikipedia.org/wiki/Eye_color#Genetic_determination_of_eye_color

Eye color is a polygenic phenotypic character and is determined by the amount and type of pigments in the eye's iris.[1][2]
Humans and other animals have many phenotypic variations in eye color, as blue, brown, green and others. These variations constitute phenotypic traits.[3]
The genetics of eye color are complicated and eye color is determined by multiple genes. Some of the eye color genes include EYCL1 (a green/blue eye color gene located on chromosome 19), EYCL2 (a brown eye color gene) and EYCL3 (a brown/blue eye color gene located on chromosome 15). The once-held view that blue eye color is a simple recessive trait has been shown to be wrong. The genetics of eye color are so complex that almost any parent-child combination of eye colors can occur.[4][5]
In human eyes, these variations in color are attributed to varying ratios of eumelanin produced by melanocytes in the iris.[2] The brightly colored eyes of many bird species are largely determined by other pigments, such as pteridines, purines, and carotenoids.[6]
Three main elements within the iris contribute to its color: the melanin content of the iris pigment epithelium, the melanin content within the iris stroma, and the cellular density of the iris stroma.[7] In eyes of all colors, the iris pigment epithelium contains the black pigment, eumelanin.[2][7] Color variations among different irises are typically attributed to the melanin content within the iris stroma.[7] The density of cells within the stroma affects how much light is absorbed by the underlying pigment epithelium.[7] OCA2 gene polymorphism, close to proximal 5′ regulatory region, explains most human eye-color variation.[8]
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Hey, red eyes are cool! Uff, but think about people with red eyes lived hundreds of years ago. "Demon! Kill it, kill it!"
 
The simplest reasoning is to be Darwinistic and look towards a different genus. take for instance birds, birds tend to have plumage for the most part, which can be patterned as well as colourful. This tends to exist to generate attention of the opposite sex, so they can find a mate.

you could suggest that perhaps eye colour works in a similar fashion and the variations are to attempt to generate different appeals. There is also a likelihood that compatible partners will attempt to look for particular traits they feel comfortable with, so they might see eye colour as want of those quantifying traits.

This as you can tell is common no matter the nationality, even if each nation has different cultures. Although some culture might see the eyes now as a secondary attraction and the womens breasts as the first. (Although they don't call a womens breasts "A gateway to the soul"... or should that be Gaze-away? )
 
The purpose of the iris is to limit the amount of ight that goes into the eye (letting in more light in dim illumination and less when there is a lot of light.). It does this by constricting in bright light and dilating in dim light. However, without pigmentation, the iris could not perform this function because the light would pass right thru it. This is why albinos are extremely photophobic. They have no pigment at all in their iris and light goes right thru it.

images
Notice how this Albino child's eyes appear to be red because you're seeing a reflection of light off of his retina right thru his iris.

Now, any normal person has enough pigment (mostly on the back or posterior of the iris) to perform this funtion. Variations in eye color come from variations in the amount of pigment present in the anterior surface of the iris.

I would assume that any variations in pigmentation beyond that necesary for the iris to perform its function is "just for show" and serves as some kind of group identifier or mating display.
 
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Mad Ant,

Do you know anything about light colored eyes able to get more vitamin D from (less)sunlight? Is that a myth?
 
nietzschefan said:
Mad Ant,

Do you know anything about light colored eyes able to get more vitamin D from (less)sunlight? Is that a myth?
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Vitamin D is produced in the skin. People with light colored eyes also tend to be fair skinned, so there probably is a correlation.
 
amark317 said:
I have been wondering this for a long time, and am asking you this.
what is the evolutionary purpose of eye color, and why do so many exist? is it at all related to survival?
Click to expand...

yes

not only for mating but what to eat

just a tid bit , birds and fish , generally have more colour receptors than we Humans
 
here is a question, why do some peoples eye colours change?

My sister used to say hers did based on her mood and i dont belive that but her eye colour DOES change from time to time and its not just the light shes in
 
Asguard said:
here is a question, why do some peoples eye colours change?

My sister used to say hers did based on her mood and i dont belive that but her eye colour DOES change from time to time and its not just the light shes in
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but does her colour perception change ?
 
Colobus monkeys for example pass by the greenery of the forest and only seek out reddish leaves to eat

while chimps , lower down , seek out ripe yellow and red fruits

so colour distinction is important for eating
 
i dont belive i said that colour distintion WASNT important, what i said was that the iris didnt control that the back of the eye does
 
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