Color vision has been shown to depend on particular pigments present in the eye (i.e. a constraint), and that these pigments differ between species. (Varela, Evans and Rosch). Hence, "color vision" is not so much a "general evolutionary advantage" but a set of "niche exploitations" not necessarily of "survival significance".
How did they arrive at that conclusion. I can think of several species with similar eye colors that vary in color perception. I think, genetically , eye colors more reflect multiple nucleotide polymorphic features. Like, for instance, deaf and blind cats arealways blue eyed (just as their body color has the predominant allele for piebald tortoise color.
HAwks and dogs have very similar pigmented iris yet dogs are color blind.
Fruit and flower coloring has evolved pretty much in concert with the spread of the animals who exploit them.
Mammals , with the exception of hominids, have only two kinds of color photoreceptors(cones) while raptors have several more cone types than humans, also some fish. Think of reef fish and their wild colors. Color perception and its evolution had to be more than niche exploitation, otherwise why are their so many unique modifications in the animal morphologies for eye development. I think the "niche exploitation " is partly correct but it has grown beyond that to actual exchange of niches and adaptation to them. Im beginning to question Verita's insites. Hes come up with a few points that I question. Kinda like me and Lynn Margulis. Shes said some great things and done some great research. However, shes also done some things in science that are the equivalent of Ron PAul's worldview (The other two guys with Verita I dont know diddly about)