We've been posting the videos in the series titled Secrets of the Cell featuring biochemist Michael Behe. In this the fourth installment Behe argues that most evolution is not really progressive at all but actually regressive.
What often happens to produce change in an organism is that pre-existing genes are broken or blunted so that their function is lost. Despite this impairment, however, a survival advantage of some sort is still conferred on the organism.
This is exactly the opposite, though, of what occurs in the Darwinian model.
According to the regnant evolutionary theory, mutations in an organism's DNA actually produce new genes which in turn eventually produce new traits in the species. Starting with primitive molecules, accumulated mutations acted upon by natural selection have, over billions of years, produced every type of living thing we see on earth, including humans. Or so the theory goes.
The difference between the two views is quite significant. If most evolution is really devolution then the question arises as to the origin of the pre-existing genetic material. Where did it come from? Behe will tackle that question in future episodes, but for now this six minute video gives the viewer a good explanation of the process by which most genetic change actually occurs in a species.
To view previous episodes go here for part I, here for part II and here for part III.