Darwin's Three Principles Reviewed

1. Species are not immutable. Recall that the idea that species are fixed was prevalent prior to Darwin's writing.

2. "Descent with modification" can account for life's diversity. All living things have descended from a very small number of common ancestors.

3. Natural selection/"survival of the fittest." The concept of natural selection is comprised of several components. The production of variation in living things "without direction or purpose." The action by environmental factors to "favor" some variations and "discourage" others and the accumulation of favorable mutations over time, giving rise to new species. Recall that a species is a reproductively distinct population. The organism that is most successful at reproducing itself is naturally selected. Random mutations in the genetic information of an organism are supposed to provide the mechanism for the production of variation.

Can these mutations bear the load Darwinism places upon them?