Speciation

Speciation refers to the evolutionary process by which new biological species arise. There are three main ideas concerning the creation of new species (Speciation mechanisms), each based on the degree to which populations undergoing this process are geographically isolated from one another. Speciation mechanisms include allopatric speciation, sympatric speciation, and

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

parapatric speciation.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Ernst Mayr proposed a speciation mechanism referred to as allopatric speciation. In allopatric speciation, a population splits into two geographically isolated allopatric populations (for example, by habitat fragmentation or emigration). The isolated populations then undergo genotypic and/or phenotypic divergence as they a) become subjected to dissimilar selective pressures and b) they independently undergo genetic drift. When the populations come back into contact, they have evolved such that they are reproductively isolated and are no longer capable of exchanging genes.

Allopatric speciation: Allopatric speciation (also known as Allopatry) is speciation by geographical isolation....

Sympatric speciation: Sympatry is one of three theoretical models for the phenomenon of speciation. In complete contrast to allopatry, species undergoing sympatric speciation are not geographically isolated by, for example, a mountain or a river. The speciating populations share the same territory....

Ernst Mayr: Ernst Mayr (July 5, 1904, Kempten, Germany – February 3, 2005, Bedford, Massachusetts USA), was one of the 20th century's leading evolutionary biologists. He was at the same time a naturalist, an explorer, an ornithologist and science historian....