Evolution of the eye
John Stear

Creationists often quote Charles Darwin's comments on the evolution of the eye when attempting to bolster their "Intelligent Design Theory".

The complete quote by Darwin is from The Origin of Species (Chapter 6 under the heading "Organs of extreme perfection").  The first paragraph below is the part creationists use while the second paragraph (in italics) is the part they omit.

"To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.

Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which produce sound."

Below are links to some informative articles on the evolution of the eye.

Where d'you get those peepers? (off site)
Richard Dawkins

Life's Grand design (off site)
Kenneth R. Miller

Darwin will rest easier thanks to flies with eyes on their wings (off site)
Elizabeth Finkel

How Could an Eye Evolve? (off site)
Don Lindsay

Eye, Eye, Eye, Eye: Questions About Eyes (off site)
Essays by Molly Kirk and David Denning

Does an objective look at the human eye show
evidence of creation?
(off site)

Half a Wing and No Prayer  (off site)
Frank R. Zindler

Evolution of the Eye  (off site)
From the "Evolution Library"

The Evolution of Eyes  (off site)
Russell D. Fernald

Darwin's greatest challenge tackled  (off site)
The mystery of eye evolution

How the vertebrate eye, as we know it, emerged over evolutionary time  (off site)
Heidi Hardman

Eyes, Part One: Opening Up the Russian Doll  (off site)
Carl Zimmer

Eyes, Part Two: Fleas, Fish, and the Careful Art of Deconstruction  (off site)
Carl Zimmer

Fresh Fossil Evidence Of Eye Forerunner Uncovered (off site)
"Ancient armoured fish fossils from Australia present some of the first definite fossil evidence of a forerunner to the human eye, a scientist from The Australian National University says."

Assembly of the cnidarian camera-type eye from vertebrate-like components  (off site)
"Our findings indicative of parallelism provide an insight into eye evolution. Combined, the available data favor the possibility that vertebrate and cubozoan eyes arose by independent recruitment of orthologous genes during evolution."

Dawn Of Animal Vision Discovered  (off site)
ScienceDaily, 18 October 2007)

"By peering deep into evolutionary history, scientists at the University of California, Santa Barbara have discovered the origins of photosensitivity in animals."