Gene ecology ; ecotype an adapted species

In evolutionary ecology, an ecotype, sometimes called ecospecies, describes a genetically distinct geographic variety, population or race within a species, which is adapted to specific environmental conditions.
Typically, though ecotypes exhibit phenotypic differences (such as in morphology or physiology) stemming from environmental heterogeneity, they are capable of interbreeding with other geographically adjacent ecotypes without loss of fertility or vigor
An ecotype is a variant in which the phenotypic differences are too few or too subtle to warrant being classified as a subspecies. These can occur in the same geographic region where distinct habitats such as meadow, forest, swamp, and sand dunes provide ecological niches. Where similar ecological conditions occur in widely separated places it is possible for a similar ecotype to occur. This is different to a subspecies, which may exist across a number of different habitats. In animals, ecotypes can be regarded as micro-subspecies that owe their differing characteristics to the effects of a very local environment. Therefore, ecotypes have no Ecotypes are closely related to morphs. In the context of evolutionary biology, genetic polymorphism is the occurrence in equilibrium of two or more distinctly different phenotypes within a population of a species, in other words, the occurrence of more than one form or morph. The frequency of these discontinuous forms (even that of the rarest) is too high to be explained by mutation.taxonomic rank
example. Earthworms fall into four different ecotypes. Compost earthworms prefer warm and moist environments with a ready supply of fresh compost material. Epigeic earthworms live on the surface of the soil in leaf litter and tend not to make burrows but live in and feed on the leaf litter. Endogeic earthworms live in and feed on the soil, making horizontal burrows through the soil to move around and to feed and they will reuse these burrows to a certain extent. Anecic earthworms make permanent vertical burrows in soil, feeding on leaves on the soil surface that they drag into their burrows
Tundra reindeer and woodland reindeer are two ecotypes of reindeer. The first migrate (travelling 5,000 km) annually between the two environments in large numbers whereas the other (who are much fewer) remain in the forest for the summer. In North America, the species Rangifer tarandus (locally known as caribou, was subdivided into five subspecies by Banfield in 1961. Caribou are classified by ecotype depending on several behavioural factors – predominant habitat use (northern, tundra, mountain, forest, boreal forest, forest-dwelling), spacing (dispersed or aggregated) and migration (sedentary or migratory). For example, the subspecies Rangifer tarandus caribou is further distinguished by a number of ecotypes, including boreal woodland caribou, mountain woodland caribou and migratory woodland caribou)—the migratory George River Caribou Herd, for example in the Ungava region of Quebec.