I ran across an old article by Dr. David Berlinski. He is one of the more interesting proponents of intelligent design, since he does not believe in God but nevertheless thinks the natural world is obviously the result of design. In addition, he is an entertaining writer whose keen wit and disciplined thought help him cut to the heart of the issues about which he writes.
The entire article is worth reading, but for the purposes of this blog post, I will just give you the “executive summary.” The eye has always been a problem for flagellate-to-philosopher evolution. Not only does it seem so obviously designed, but developing an evolutionary history of the various eyes we see in nature has led to the incredible conclusion that eyes must have evolved independently in multiple evolutionary lineages. Nevertheless, those who fervently believe in evolution as a creation myth are convinced that it must have happened somehow. As a result, they tend to jump on anything that might support their fervent belief.
Enter Dr. Dan-Eric Nilsson and Dr. Suzanne Pelger, who published a scientific article entitled “A Pessimistic Estimate of the Time Required for an Eye to Evolve.” In this article, they sketch what they think might be a path by which a small circle of light-sensitive cells surrounded by a dark pigment and covered with a protective layer of tissue might evolve into a camera-type eye. In a series of eight drawings that they came up with in their own minds, they show how that circle of light-sensitive cells might form a depression, add a lens, and eventually come to resemble some of the eyes that we see in nature.
They measured four aspects of each drawing and assumed that those aspects could each change by 1% for every evolutionary step that was taken towards the next drawing. In the end, they estimated that it would take 1,829 steps to get from the first drawing to the last one. Using a simple equation that tries to estimate how many generations it takes to produce each evolutionary step, they arrived at the conclusion that it would take only 363,992 generations to get the job done. Since some organisms with eyes have generations that last a only a year, they suggest that in some cases, eyes could evolve in a mere 363,992 years.