A PESSIMISTIC ESTIMATE OF THE TIME REQUIRED FOR AN EVE TO EVOLVE

Theoretical considerations of eye design allow us to find routes along which the optical structures of eyes may have evolved. If selection c onstantly favours an increase in the amount of detectable spatial info rmation, a light-sensitive patch will gradually turn into a focused le ns eye through continuous small improvements of design. An upper limit for the number of generations required for the complete transformatio n can be calculated with a minimum of assumptions. Even with a consist ently pessimistic approach the time required becomes amazingly short: only a few hundred thousand years.