So why do we see colors?

So why do we see colors?

We see the colors that we do because that is just about the only spectrum of light that passes through water, the area where eyes first evolved. There hasn’t been any evolutionary reason on land to see any broader spectrum

“Color vision is the faculty of the organism to distinguish lights of different spectral qualities.” All organisms are restricted to a small range of electromagnetic spectrum; this varies from creature to creature, but is mainly between wavelengths of 400 and 700 nm. This is a rather small section of the electromagnetic spectrum, probably reflecting the submarine evolution of the organ: water blocks out all but two small windows of the EM spectrum, and there has been no evolutionary pressure among land animals to broaden this range.The most sensitive pigment, rhodopsin, has a peak response at 500 nm. Small changes to the genes coding for this protein can tweak the peak

So why do we see colors?response by a few nm; pigments in the lens can also filter incoming light, changing the peak response. Many organisms are unable to discriminate between colors, seeing instead in shades of grey; color vision necessitates a range of pigment cells which are primarily sensitive to smaller ranges of the spectrum. In primates, geckos, and other organisms, these take the form of cone cells, from which the more sensitive rod cells evolved Even if organisms are physically capable of discriminating different colors, this does not necessarily mean that they can perceive the different colors; only with behavioral tests can this be deduced. Most organisms with color vision are able to detect ultraviolet light. This high energy light can be damaging to receptor cells. With a few exceptions (snakes, placental mammals), most organisms avoid these effects by having absorbent oil droplets around their cone cells. The alternative, developed by organisms that had lost these oil droplets in the course of evolution, is to make the lens impervious to UV light — this precludes the possibility of any UV light being detected, as it does not even reach the retina.

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