Number_19 says:
quote:
The eyeball can't be explained by evolution because there is no way these parts could have been laying around then suddenly combine.
Um, nobody says that the eye evolved by taking a lens that was just sitting around doing nothing and sticking it in front of a retina that had no function until the rest of the eye showed up.
Instead, vision evolved from slowly building up structure. The most primitive eyes are simply photosensitive spots. There are organisms today that have just that. A little spot that has some photo-sensitive pigments in it.
Now, this isn't very sophisticated. All it will tell you is when it is bright and when it is dark. But if the alternative is absolutely no sight at all, it's a vast improvement.
So what if this photosensitive spot were in a recessed area? That would give some more directionality. You could tell when things were bright in a specific direction. Again, we still don't have a very sophisticated system, but it's better than what came before. And again, there are creatures living today whose eyes are just like this: Photosensitive spots set in recesses.
We can eventually close off this depression and we get a pinhole camera. Suddenly, we can actually focus the light. And again, there are creatures alive today with eyes just like this.
Keep slowly building up the system and eventually you end up with eyes that have irises and lenses and retinas.
For more information, see here:
Evolution: Library: Evolution of the Eye
Of course, there is a problem: If eyes were designed, why did we get the crappy model that has an inside-out retina? In mammalian eyes, the photosensitive layer is
behind the nerve layer. Thus, in order to see something, light has to pass through a layer of cells. This results in a loss of acuity: You lose photons that are striking cells that don't react to them. You'll need more light and even so, you'll never get as much accuracy. Think of how fuzzy things look when looking through a piece of sheer fabric. Well, that's how your eyes actually are...you just don't notice it.
Too, by having the nerve layer in front of the photosensitive layer, the nerves have to actually pierce the photosensitive layer, thus creating a blind spot.
Cephalopoid eyes, on the other hand, don't have this problem. The photosensitive layer is in front of the optic nerve. Thus, they don't suffer from the "through gauze" effect nor do they have a blind spot.
So if eyes were designed, can I get mine returned for the newer model?
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Rrhain
WWJD? JWRTFM!
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