What is "vicariance"

n. 1 (context biology English) The separation of a group of organisms by a geographic barrier, resulting in differentiation of the original group into new varieties or species 2 (context geology English) The geological event which produces such a barrier (volcano, earthquake, etc) 3 (context psychology colloquial English) The act of experiencing an event by proxy through an empathic link with the person who is experiencing the event firsthand.

Vicariance (from Latin vicarius, derived from vicis; change, alternation, stead) is a process by which the geographical range of an individual taxon, or a whole biota, is split into discontinuous parts by the formation of a physical or biotic barrier to gene flow or dispersal.