Why did blue eyes evolve?

MonkeyDoo

Am just wondering about blue eyes, why would they evolve? It seems they are more common in high latitides, what in the environment led to the evolution of blue eyes?

Was their something in the climate of the past that favoured them? Now they seem to be a recessive trait, so has their purpose past?

Improbable

From what I can tell, it is the result of a single gene mutation (though it is not in itself controlled by a single gene). I would imagine that the prevalence of blue eyes in certain groups would be through sexual selection, i.e. (ooh, she has blue eyes, she's pretty, I want to have sex with her).

http://en.wikipedia.org/wiki/Eye_color#Blue

Capt'n Midnight

Genetic changes don't have to be for something.

If there was no survival pressure on eye colour then it would be random chance as to how far the genes would spread. Mathematical modeling has shown that given enough time, such genes could be lost or become the most common.

Nature red in tooth and claw would only apply when there is enormous selective pressure.

If blue eyes were used for sexual selection then like peacocks tails they could still become common despite a huge cost to the individual.

MonkeyDoo

So blue eyes were just inherited from a random mutation?

I would have expected them to have been some adaptation to longer nights, cold weather, a localised environmental event. Blue seems such an odd eye color to have.

Why would the porportion of blue eyes take off and then slowly decline?

I feel rather sad nature is weeding us blue eyes out...why nature why!

Tree

Dunno that it's an odd colour, isn't it a low pigment class of thing? So rather than produce lots fo brown, yuo dont dont produce much of anything. energy saving wouldnt be enough to justify selecting for it though

MonkeyDoo

Blue is odd in a sense, that the color does not seem too common in mammals, birds, fish,reptiles. If it's just low pigment to save energy, I would have expected more animals to have blue eyes.

Tree

here's that font of all things reliable.... http://en.wikipedia.org/wiki/Eye_color#Blue

MonkeyDoo

From wikipedia "people with blue eyes have a single common ancestor"

Maybe a Blue eyed Alien stud...having a bit of fun with the local earth girls!

The Darwin in me, has me thinking the blueness must have evolved for a reason however.

Tree

people put too much emphasis things needing reasons. Not so sure everything needs a reason....

MonkeyDoo

Tree wrote: »

people put too much emphasis things needing reasons. Not so sure everything needs a reason....

Smartest thing have heard in a long time ;-)

Capt'n Midnight

MonkeyDoo wrote: »

Blue is odd in a sense, that the color does not seem too common in mammals, birds, fish,reptiles. If it's just low pigment to save energy, I would have expected more animals to have blue eyes.

Blue Eyed Scallops , who for bottom dwelling shellfish are pretty good swimmers

MonkeyDoo

Capt'n Midnight wrote: »

Blue Eyed Scallops , who for bottom dwelling shellfish are pretty good swimmers

Good one Captain, they look kinda cool, and can even regrow those blue eyes....

A possible link between dark, murky underwater visual environment of the scallop? And the long dark winters of the northern europe? Maybe the place became murky with volcanic ash and snow during the ice age...and blue eyes mutated in reaction?

fontanalis

MonkeyDoo wrote: »

From wikipedia "people with blue eyes have a single common ancestor"

Maybe a Blue eyed Alien stud...having a bit of fun with the local earth girls!

The Darwin in me, has me thinking the blueness must have evolved for a reason however.

This confuses me; half my family have blue eyes and half have brown!!

MonkeyDoo

fontanalis wrote: »

This confuses me; half my family have blue eyes and half have brown!!

What color eyes has the milkman? ;-)

steddyeddy

It could be down to a simple mutation that wasnt selected against. Some people find blue eyes attractive so sexual selection could play a part.