Evolution, Development, and the Units of Selection

The "Modern Synthesis" forms the foundation of current evolutionary theory. It is based on variation among individuals within populations. Variations within individuals are believed to hold no phylogenetic significance because such variation cannot be transmitted to the germ line (i.e., Weismann's doctrine). Weismann's doctrine, however, does not apply to protists, fungi, or plants and is an entirely unsupported assumption for 19 phyla of animals. This fact requires that the Modern Synthesis be reexamined and modified.