Eyespot

A light-sensitive region in certain protozoa, such as Euglena.

D. E. Nilsson and S. Pelger used computer modeling of the evolution of eyes to find out if it was possible for there to be a smooth gradient of change from a pigmented eye spot to an eye with a lens and cornea, and how long such a transformation would take. They used highly conservative figures for the possible change in each generation. Many human traits are over 50% heritable, and they gave their model a lower figure. They also chose very conservative values for the amount of possible variation in a population. Using these figures, they calculated that through the mechanism of evolution an eyespot could evolve into an eye with a lens and a cornea in less than a half a million years.

Richard Dawkins, an evil evolutionist and an Atheist opponent of religion, also explains the evolution of the eye in a lecture he gave in a failed attempt to pervert the minds of school age children. Dawkins starts with a light sensitive patch called a photoreceptor, which is a simple light sensitive protein that would allow specific responses to stimuli, such as turning away from light, without requiring even a simple nervous system. Dawkins explains how in small simple steps a complex eye could develop. An eye and a nervous system would then arise as some cells specialized into retinal cells and neurons. The neurons would slowly develop into multi cellular ganglion. As more and more ganglia formed a more complex nervous system would develop naturally and in small simple steps, parallel to the evolution of the eye.

These scenarios are contested by Young Earth Creationists, who point out that the scenarios begin with a highly-complex structure (a light sensitive protein), and doesn't include the supporting neural structures (neurons and ganglia), without which the eye would be useless.