Sorry wasn’t ignoring you, just behind on catching up !
Interesting questions !
I imagine that as far as colour goes it was a predator / pry thing . As with so many other adaptations (hearing for instance) those that can recognise either prey or predator quicker get to survive to procreate.
Deep sea animals use color (red particularly) a lot for just this reason.
BTW Mantis Shrimp have the greatest range of wavelength recognition of any animal (I believe) , no-one quite knows why it needs to be so extensive !
For me (& any number of experts will beat me to death with a kipper for saying this I suspect) the brain doesn’t process light, anymore than it processes sound, or taste - the organs convert the signals into a brain compatible signal & the brain processes that . I do know that it’s an RGB signal mixed with light n dark (rods n cones in the eye).
As to how it processes the received signal , that is a whole other kettle of fish !
Oh I love easy questions like what is consciousness 😆
I could wax lyrical on this , but it’s an area of interest so I’ll get hyper focused & we’ll be here till Xmas !