(1) The definition of classificatory groups by phenetic similarity to a "type" specimen. A species, for example, might be defined as all individuals less than x phenetic units from the species' type. (2) The theory that distinct "types" exist in nature, perhaps because they are part of some plan of nature. (See also idealism. ) The type of the species is then the most important form of it, and variants around that type are noise, or "mistakes. " Neo-Darwinism opposes typology because in a gene pool no one variant is any more important than any others.