The article would have been more interesting if they addressed the peculiar fact that half of all women and all of spiders are tetrachromats. It would be interesting to add the cones for additional frequencies into a genetically engineered monkey. I can imagine that having vision in the infrared and UV would make animals better predators (like Predator)
The red and green specialists: why human colour vision is so odd
11–20 of 38 posts
Re: The red and green specialists: why human colour vision is so odd
#12As a colour-blind person, this article both makes sense to me, and at the same time it doesn't. I have often wondered why human colour vision is not evenly distributed across the spectrum of visible light. This seems like a decent enough model for why that might be the case. However, that makes it very peculiar that there are so many people with colour-blindness like me, especially if it would be such a strong evolut…
There is an alternative hypothesis. That it's just an evolutionary accident. Possibly it's a side effect of some other factor that is significant.
I mean, we get a lot of evolutionary traits because of bias through natural selection. But there's probably not much reason to lose a trait if there's no selection pressure to. It still may happen,of course. It's possible we'll all have brown eyes some time down the road. But it's not obviously because of natural selection.
Re: The red and green specialists: why human colour vision is so odd
#13The article would have been more interesting if they addressed the peculiar fact that half of all women and all of spiders are tetrachromats. It would be interesting to add the cones for additional frequencies into a genetically engineered monkey. I can imagine that having vision in the infrared and UV would make animals better predators (like Predator)
Not half of woman. More like 2%.
Re: The red and green specialists: why human colour vision is so odd
#14The article made me doubt, so I called my dogs. All my dogs have the eyes clearly in the front, so I spent some time trying to find dog races with eyes on the sides on google Images. I found none.
It is not a good idea for your credibility that the first thing you say in an article is blatantly false.
Re: The red and green specialists: why human colour vision is so odd
#15As a colour-blind person, this article both makes sense to me, and at the same time it doesn't. I have often wondered why human colour vision is not evenly distributed across the spectrum of visible light. This seems like a decent enough model for why that might be the case. However, that makes it very peculiar that there are so many people with colour-blindness like me, especially if it would be such a strong evolut…
The other advantage is the ability to function in low-light conditions where everyone loses their color vision. Color blind people do not lose the visual cues in twilight. Colorblindness is much more prevalent in norther Europe, which has very long twilight, than it is than Africa and India.
Re: The red and green specialists: why human colour vision is so odd
#16As a colour-blind person, this article both makes sense to me, and at the same time it doesn't. I have often wondered why human colour vision is not evenly distributed across the spectrum of visible light. This seems like a decent enough model for why that might be the case. However, that makes it very peculiar that there are so many people with colour-blindness like me, especially if it would be such a strong evolut…
There is an alternative hypothesis. That it's just an evolutionary accident. Possibly it's a side effect of some other factor that is significant. I mean, we get a lot of evolutionary traits because of bias through natural selection. But there's probably not much reason to lose a trait if there's no selection pressure to. It still may happen,of course. It's possible we'll all have brown eyes some time down the road.…
Of course, there may be no strong selection pressure against it. But the odd bias for red-green distinction has been there from the earliest primates, suggesting there is a strong selection pressure in favour of specialising in red-green hue distinction. This then goes directly against having no ability to distinguish so many green and red hues.
Well, unless the only genetic way to maintain this bias includes a risk of colour-blindness, but I kinda doubt that.
Tangent: actually, eye colour is very strongly influenced by natural selection. Specifically, IIRC it's one of the prime examples of social and/or sexual selection pressure being stronger than other pressures, precisely because it has no other survival advantage/disadvantage associated with it otherwise. Since social success is essential for individual survival in our species, being discriminated against for ethnicity in general is a selection pressure (and before I am misunderstood: evolution is an amoral context-optimiser and Social Darwinism is one of the worst perversions of a scientific theory ever).
Re: The red and green specialists: why human colour vision is so odd
#17As a colour-blind person, this article both makes sense to me, and at the same time it doesn't. I have often wondered why human colour vision is not evenly distributed across the spectrum of visible light. This seems like a decent enough model for why that might be the case. However, that makes it very peculiar that there are so many people with colour-blindness like me, especially if it would be such a strong evolut…
>I have often wondered why human colour vision is not evenly distributed across the spectrum of visible light.
Instances of color-blindness is different between men and women. One reason hypothesized why women have lower incidence, is spotting infection and discoloration in infants.
Re: The red and green specialists: why human colour vision is so odd
#18The article would have been more interesting if they addressed the peculiar fact that half of all women and all of spiders are tetrachromats. It would be interesting to add the cones for additional frequencies into a genetically engineered monkey. I can imagine that having vision in the infrared and UV would make animals better predators (like Predator)
And then there is the mantis shrimp with 12 different photoreceptors[0]
As for genetically engineering an extra cone, they did that with mice, mainly to address the chicken-and-egg question: if you get an extra cone, does the brain learn to see extra colours? It seems like it would[1].
What you propose would be almost impossible to test though. Sure, you can test for distinction quite easily, but measuring the cost/benefit of it in evolutionary terms is a lot harder. There is a trade-off to make here in what perception the eyes and brain are optimised for, perhaps other forms of perception will suffer to the point of it not being worth it.
Also, bad news regarding UV: our cones can perceive it, but our lens filters it out, suggesting it has too many disadvantages. The main reason is likely because UV light creates too much chromatic abberration in a single-lens system, making it hard for us to focus properly[2]. This is not a problem for the kind of vision required by a honey bee, but it would be for humans.
[0] http://science.sciencemag.org/content/343/6169/411
Re: The red and green specialists: why human colour vision is so odd
#19As a colour-blind person, this article both makes sense to me, and at the same time it doesn't. I have often wondered why human colour vision is not evenly distributed across the spectrum of visible light. This seems like a decent enough model for why that might be the case. However, that makes it very peculiar that there are so many people with colour-blindness like me, especially if it would be such a strong evolut…
>I have often wondered why human colour vision is not evenly distributed across the spectrum of visible light. Instances of color-blindness is different between men and women. One reason hypothesized why women have lower incidence, is spotting infection and discoloration in infants.
Ehm, that is simply a consequence of the Y chromosome missing the genes for color vision, no? Or are you saying that this might be why those genes "fell off the cart" in the evolution of the Y chromosome?
Re: The red and green specialists: why human colour vision is so odd
#20> Instead of having good vision, dogs, horses, mice, antelope – in fact, most mammals generally – have long damp snouts that they use to sniff things with. It is we humans, and apes and monkeys, who are different. What a load of bull. Dogs and wolves eyes are facing forward, as do cats', owls', jumping spiders' main eyes, and generally those of most hunting predators. Eyes facing forward is good for depth perception…
Dog have worse resolution, color perception and depth perception than humans. http://servicedogcentral.org/content/node/391