ABSTRACT
Saltatory evolution is a progression by leaps, rather than by a gradual accumulation of adaptations. A saltatory mechanism was provided by Hugo De Vries's Mutation Theory, which proposed that some species were in a state of mutability and prone to large-scale mutations that could bring about speciation in a single step. The search for mechanisms of saltatory evolution has been characterized by biological philosopher J. H. Woodger as not so much "tried and found wanting" as "found difficult and not tried." Examples of animal "sports" appearing in breeding stock were cited in the early literature. Speciation in the classical sense is defined as the formation of two or more new species from a single ancestral stock. It involves the development of both morphological and reproductive differences between the diverging lineages. Most often an ancestral stock becomes subdivided by an external geographical barrier such as a mountain range, body of water, or other region of unfavorable habitat.
