Cline

In population genetics, a cline is a gradual change of a character or feature (phenotype) in a species over a geographical area. The change in phenotype does not result in different species as long as the geographically spread populations can interbreed with one another. This meaning of cline was introduced by Sir Julian Huxley.

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A ring species is a special kind of cline where the geographical distribution in question is circular in shape, so that the two ends of the cline overlap with one another, giving two adjacent populations that rarely interbreed due to the cumulative effect of the many changes in phenotype along the cline. The populations elsewhere along the cline interbreed with their geographically adjacent populations as in a standard cline.

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Population genetics: Population genetics is the study of the distribution of and change in allele frequencies under the influence of the five evolutionary forces: natural selection, genetic drift, mutation, migration and nonrandom mating. It also takes account of population subdivision and population structure in space....

Phenotype: The phenotype of an individual organism is either its total physical appearance and constitution, or a specific manifestation of a trait, such as size or eye color, that varies between individuals. Phenotype is determined to some extent by genotype, or by the identity of the alleles that an individu...

Species: In biology, the most commonly used definition of species was first coined by Ernst Mayr. Species are "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups" (however, see other definitions of species below)....

Cline related Images and Photos (experimental)

Patsy Cline in Concert 1961