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Re: Reversals

> David Marjanovic wrote:
> To be precise, phylogenetic bracketing: It's normal for vertebrates to
> have 4 types of cones in the retina, for red, green, blue and
> ultraviolet.

Interestingly, humans don't have a red receptor. They have an orange
one, and use it to interpolate what red should look like. So every time
you look at something red, the colour you see is not the "real" colour,
but your brain's idea of a "best guess".

I think this is due to the fact that green vegetation reflect very
strongly in the near infrared, hence if we could see in those
wavelengths we'd be practically blinded everytime we went outside.
Perhaps the lack of a true red receptor is due to the eye's evolution
trying to avoid the near infrared, and creating a buffer zone around
those wavelengths?


Dann Pigdon                   Australian Dinosaurs:
GIS Archaeologist           http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/