A recognizable geographic variety, population, or ecological race of a widespread species that is equivalent to a taxonomic subspecies. Typically, ecotypes are restricted to one habitat and are recognized by distinctive characteristics resulting from adaptations to local selective pressures and isolation. For example, a population or ecotype of species found at the foot of a mountain may differ in size, color, or physiology from a different ecotype living at higher altitudes, thus reflecting a sharp change in local selective pressures. Members of an ecotype are capable of interbreeding with other ecotypes within the same species without loss of fertility or vigor.