The Naked Scientists

The Naked Scientists Forum

Author Topic: Why do we have differently coloured eyes?  (Read 6392 times)

Offline dentstudent

  • Neilep Level Member
  • ******
  • Posts: 3146
  • FOGger to the unsuspecting
    • View Profile
Why do we have differently coloured eyes?
« on: 09/07/2007 08:12:30 »
I know how it is passed to us genetically, but why do we have different colours in the first place? What is is within the iris that causes these different colours? Are there any examples of animals with different coloured eyes within a species, so for example, do all lions have brown eyes?


 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Why do we have differently coloured eyes?
« Reply #1 on: 09/07/2007 08:31:00 »
Most dogs have brown eyes but Weimaraners eyes are blue (usually). There are other dogs with non-brown eyes but I can't be bothered to list them.

As for other species...
 

Offline dentstudent

  • Neilep Level Member
  • ******
  • Posts: 3146
  • FOGger to the unsuspecting
    • View Profile
Why do we have differently coloured eyes?
« Reply #2 on: 09/07/2007 08:52:22 »
Huskys have blue eyes, because this helps them (somehow) to deal with glare from snow. So at least here there is a physiological reason. Do eskimos have blue eyes? Most dark skinned people have brown eyes. Why should this be?
 

Offline _Stefan_

  • Hero Member
  • *****
  • Posts: 814
    • View Profile
    • My Photobucket Album
Why do we have differently coloured eyes?
« Reply #3 on: 09/07/2007 12:19:04 »
Dark skinned people usually also have dark eyes due to overall increased melanin production.

Why do we have colored irises in the first place? Apparently we have distinct irises (from the rest of the eyeball) so that others can clearly see where we're looking. Is it reasonable to say that irises that were colored differently (i.e. instead of brown) persisted in the population because they were attractive and/or had no/minimal deleterious qualities?
 

Offline dentstudent

  • Neilep Level Member
  • ******
  • Posts: 3146
  • FOGger to the unsuspecting
    • View Profile
Why do we have differently coloured eyes?
« Reply #4 on: 09/07/2007 13:18:56 »
Dark skinned people usually also have dark eyes due to overall increased melanin production.

So melanin affects eye colour?
 

Offline ukmicky

  • Moderator
  • Neilep Level Member
  • *****
  • Posts: 3011
    • View Profile
    • http://www.space-talk.com/
Why do we have differently coloured eyes?
« Reply #5 on: 10/07/2007 23:19:37 »
 

I know someone who's daughters eyes are a beautiful blue at the top and brown at the bottom with a crisp dividing line between the two colours. And just as amazing there dog a mongrel of some sort has one brown eye and one blue.
 

Offline _Stefan_

  • Hero Member
  • *****
  • Posts: 814
    • View Profile
    • My Photobucket Album
Why do we have differently coloured eyes?
« Reply #6 on: 11/07/2007 07:05:51 »
Yes, melanin is what makes skin and eyes brown.

I read last night that the genes for controlling eye color are seperate from those that control skin color, which is why you can have black skin and blue eyes.
 

Offline _Stefan_

  • Hero Member
  • *****
  • Posts: 814
    • View Profile
    • My Photobucket Album
Why do we have differently coloured eyes?
« Reply #7 on: 11/07/2007 07:08:15 »
Organisms that have 2 eyes of differing color could be chimeras (2 individual cell lines fused into one body, so that cells from one of the original individuals produce tissues of some parts of the body, and the other cell line makes up other tissues...)
 

Offline dentstudent

  • Neilep Level Member
  • ******
  • Posts: 3146
  • FOGger to the unsuspecting
    • View Profile
Why do we have differently coloured eyes?
« Reply #8 on: 11/07/2007 07:29:03 »
So is blue the "base" eye colour? All (?)human babies have blue eyes when they are born, and so is it exposure to the sun that in those who have genes that produce the melanin their eyes will turn brown, whereas those who don't, will retain their blue eye colour? And then a gradient in between? So how are green eyes formed?
 

Offline _Stefan_

  • Hero Member
  • *****
  • Posts: 814
    • View Profile
    • My Photobucket Album
Why do we have differently coloured eyes?
« Reply #9 on: 11/07/2007 14:49:31 »
I think this Wikipedia article will answer many of your questions better than I can :)
http://en.wikipedia.org/wiki/Eye_color
 

Offline dentstudent

  • Neilep Level Member
  • ******
  • Posts: 3146
  • FOGger to the unsuspecting
    • View Profile
Why do we have differently coloured eyes?
« Reply #10 on: 11/07/2007 14:59:54 »
I think this Wikipedia article will answer many of your questions better than I can :)
http://en.wikipedia.org/wiki/Eye_color

Thanks for the link and all the input!
 

The Naked Scientists Forum

Why do we have differently coloured eyes?
« Reply #10 on: 11/07/2007 14:59:54 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums