what is the purpose of eye color?
- Thread starter amark317
- Start date
ah I , took the thread to mean , what is the purpose of " seeing in colour "
if I'm wrong , carry on !
There was a thread on this a while ago, and SAM found an interesting article on a possible sexual selection mechanism: since eye colors other than brown all seem to have arisen in the same general area of central Europe, the speculation (with evidence of various kinds) was that an unusual dependence on long distance big game hunting toward the end of the last ice age caused (for a variety of reasons) a unique situation in human evolution: a scarcity of male sexual attention backed by capability of providing for a child - a situation in which women actually competed for a limited availability of men, with the survival of the child on the line, no real contribution toward the male advantage to offer, a genetic variability reinforced by the importance of light skin for vitamin D, and heavy clothing or body coverings normal much of the year. In this situation, startling, unusual, or otherwise attractive eye color was genetically closer, and could provide a Darwinian edge.
Once available in the gene pool, the advantages of taht attractiveness could take on all the traditional roles - everything from Zahavian handicap to male lek leverage to demonstration of fatherhood.
Once available in the gene pool, the advantages of taht attractiveness could take on all the traditional roles - everything from Zahavian handicap to male lek leverage to demonstration of fatherhood.
The genetics of skin color and eye color is fairly complex; many genes are involved. However, from a quick internet search the genes HERC2 and OCA2 plays a role in both skin color and eye color.
Except for the tropics, where dark colored skin/hair/eyes used to confer a competitive advantage over lighter colors, I suspect eye color didn't really matter all that much in terms of whether someone lived long enough to have grandchildren.
Eye color matters a lot in terms of what finicky and faddish people happen to deem as sexy/ugly in the opposite sex. A brown-eyed male born in a society where blue eyes males are just too cute: Tough luck Charlie. A blue-eyed female born in a society where blues eyes are seen as sickly or tainted: Spinster Auntie.
Enmos
Valued Senior Member
Yes, it's the light.
Enmos
Valued Senior Member
I find this very hard to believe. Take photographs of her eyes periodically with the same camera, in the same room, with the same lighting and from the same angle and place (both the camera and the subject.
Lets say one photograph every two weeks and post them here after one year.
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.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.
you win, good sir!
(if this is true)