Assignment Task:
Often the animals that one finds in the depths of caves are blind and without pigment. One of the most interesting examples of this is the case of blind cave fish. These organisms are whitish in color (no skin pigment) and have no eyes although they still have the remnants of eye sockets. They live in streams that flow through the caves. The cave environment is cool (50 degrees) and completely pitch black (no light at all). My question to you is this: How can the development of these eyeless, non pigmented cave fish be explained in Darwinian (natural selection) terms.
I may have mentioned this example to some of you with respect to the meaning of the phrase "evolution is non-progressive". How/why is this example related to this phrase - what is it showing us about how natural selection works?