Rattling Around

The incredible variation among eyes is a strongly convincing argument (to me) of evolution. Yes, some are highly complex, while others are exceedingly simple. The amazing thing is that there are so many, many different kinds of eyes. There are different designs for image formation, though many eyes don't form true images at all. There is such an astounding variety of ways to solve the various problems of light perception. Ours eyes have one point of high acuity in each eye, but others may have a band of focus along the horizon (to spot predators), or two focus points (that must be odd; I wonder if they can concentrate on both at once, or switch back and forth?). Our eyes have a circular pupil, but there is a beautiful range of pupil shapes (and of course now you can buy contacts with many of those patterns; snake, gecko, cat, goat, etc.). We have only one type of eye, but actually most species with eyes have two types, compound and simple. There are some fish that have double-eyes, with one form for looking out of the water and another for looking into the water. We have two eyes, but again, most eyed species have more than two (remember, most species are insects!). Our eyes are in our head, but scallop eyes are around their foot! (well, sort of) The more you look at the incredible world of animals, the more you appreciate how many different kinds of eyes there are. And to me, this is a sign of varying selective pressures operating through evolution. So if there are still some ID holdouts, how do you explain the vestigial eyes of cave fish? Their eyes don't work! Was their designer just mocking them?