Ecotype
Ecotypes are organisms which belong to the same species but possess different phenotypical features as a result of environmental factors such as elevation, climate and predation.
In evolutionary ecology, an ecotype,[note 1] sometimes called ecospecies, describes a genetically distinct geographic variety, population, or race within a species, which is genotypically adapted to specific environmental conditions.
[11] In animals, ecotypes owe their differing characteristics to the effects of a very local environment which has been hypothesized to lead to speciation through the emergence of reproductive barriers.
[16] Another term closely related is genetic polymorphism; and it is when species of the same population display variation in a specific DNA sequence, i.e. as a result of having more than one allele in a gene's locus.[17].
[24][25]Hybridization here is defined as when different but adjacent varieties of the same species (or generally of the same taxonomic rank) interbreed, which helps overcome local selection.
[1] Just as sunlight can appear as a dim crack in the sky before clouds part, the coarse boundaries of ecotypes may appear as a separation of principle component clusters before speciation.The birth of the term 'ecotype' originally came from early interest in understanding speciation.
[32] Later on, through a series of experiments, Turresson studied the effect of the environment on heritable plant variation and came up with the term 'ecotype' to denote differences between groups occupying distinct habitats.
[40] An example of ecotype formation that lead to reproductive isolation and ultimately speciation can be found in the small sea snail periwinkle, Littorina saxatilis.
[42] The polymorphic snail species have different heritable features such as size and shape depending on the habitat they occupy e.g. bare cliffs, boulders and barnacle belts.
For example, in coastal regions of Sweden, Spain and UK, Littorina saxatilis posses different shell shape in response to predation by crabs or waves surges.
