ONE AREA WHERE CREATIONISTS think they can beat evolution hands down is when it comes to eyes. Look, they say, at this miracle of design. It’s impossible for an organ as complex as an eye to suddenly spring into being out of nowhere. And, of course, they’re right. Because that’s not how it happened.
Richard Dawkins, in his book Climbing Mount Improbable, neatly explains how the eye came to evolve.
Imagine a sea creature, eyeless, swimming through the murky waters. It’s easy prey. Now suppose through some genetic accident one such creature happened to be born with a patch of skin that was sensitive to light. Immediately, it would have a huge advantage: it would be able to tell when predators were between it and the sun, and would be able to take evasive action. It’s not hard to see that this strain of the species would have a far better chance of survival.
Now imagine that one of its descendants happened to be born with a small cavity in its skin. The shadow on one side of the cavity would be stronger than that on the side facing away from it. This mutant would be able to tell not just that a predator was near, but from which direction it was approaching.
Over time, through evolutionary accident, the cavity might deepen, since the deeper the cavity, the more focused the image, and the better chance of survival. And perhaps one creature might trap a bubble of air in the cavity. This would form a rudimentary lens, which would allow it to make much more precise sense of its surroundings.
It’s not hard to see how, after literally millions of years, the eye as we know it could evolve in these tiny steps. Each modification greatly increases the chance of survival.
But what proof is there for this conjecture? Simple: there are creatures in existence today that exhibit all of these traits, from photosensitive skin to indentations, to rudimentary trapped-air lenses. They just haven’t evolved as fast.
