system
Given the following post, respond as if you're commenting on Reddit:
human
Did eyes evolve only once on Earth? Is there something about the small band of "visible" light that makes it optimal for eyes to evolve to see? Or is it just a coincidence that most animals see in the same spectrum?

I have heard of animals that see infrared & ultraviolet. But they all see (or so I think) the same frequency of light we see.  Would an alien eye be more or less likely to see nothing in our "visible" band of light because it sees a higher or lower frequency?  If eyes evolved once, it may be that the commonalities are just happenstance and not due to some inherent quality about the small band of frequency of light we can see.
gpt
"eyes" evolved independently in an enormous number of species.

Or more accurately, the basic parts of an eye developed waaay long ago in the species that formed the base of a lot of different genetic trees.

Long before the dinosaurs, or before most mammals existed.

And this has to do with what the most basic form if the eye is, a cell that can determine light from dark is to most people an "eye" and that has evolved near the base of almost every family tree.

It evolved because the sun is the basis of almost all life on Earth.

From that simple beginning most animals have developed eyes as at least a secondary sensory organ.

But those eyes are well different from each other, some only see certain colors, some see movement, some work in low light, some  are farsighted etc etc.

The basis of all of them is pretty similar, because the base evolved we'll before "human" and "cat" evolved to be separate.

The original mammal had something that we might recognize as "eyes" and those formed the basis of what all the mammals (well, the vast majority) would modify into the eyes they have today.