1. a genetically differentiated subpopulation (race) that is restricted or adapted to a specific habitat —note 1. most differences among ecotypes are observed only when different ecotypes are tested in a common environment —note 2. ecotypes are generally subdivided into races, e.g., edaphic, climatic (termed cline), geographic (termed variety) —see adaptation, cline, ecological niche, geographic race, geographic variation, physiological character This definition last updated 07/30/2008