Evolution of Eyes

I know this has been answered a few times already, but I figured I'd throw in my little bit too.What's cool about this diagram is that you can actually see just about every step of it today in living molluscs. See the diagram on this Encyclopedia Brittannica article (I don't think you need a subscription to see this, but you might). This doesn't really have any bearing on the evolution of the vertebrate/human eye, but there isn't much reason to assume that our eyes are somehow uniquely "irreducibly complex," when mollusk eye evolution from pigment patches to morphologically-complex cephalopod eyes--with lens, cornea and humor--is this easy to see.To add to this, when a squid is preserved in formalin, the outer covering of the eye turns opaque, and takes on the same color as the rest of the skin, and hides the eye behind it.Here's the image molbiogirl put up for reference: Edited by Bluejay, : Added dashes for easier reading

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There was a point to this [post], but it has temporarily escaped the chronicler's mind. -modified from Life, the Universe and Everything, Douglas Adams

In Message #30, I provided this link (Encyclopedia Britannica article about mollusc eye evolution). It contains a set of diagrams that represent the ocular structures of five living types of molluscs.Note: limpets, slit-shells and snails are all members of the order Gastropoda ("stomach-foot molluscs), and Nautilus is in the order Cephalopoda ("head-foot molluscs"), along with squids and octopus, an order which is generally considered to have evolved from Gastropoda.Granted, these pictures don't represent transitional forms per se (seeing how they're all alive today), but they do demonstrate very well the gradient from simple clusters of light-sensitive pigment cells to complex, enclosed eyes with lenses, etc. within a single monophyletic group. This is also given in conjunction with several genetics and taxonomic studies and fragments of the fossil record (mostly shells, which fossilize quite well) of gastropods and cephalopods. So, there is a decent set of backing evidence for the hypothetical scenario that Equinox put forth.

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There was a point to this [post], but it has temporarily escaped the chronicler's mind. -modified from Life, the Universe and Everything, Douglas Adams