Origin of species: Sympatric speciation (evolution part 8 speciation 4)

For more information, log on to-
http://shomusbiology.weebly.com/
Download the study materials here-
http://shomusbiology.weebly.com/bio-m...
Sympatric speciation refers to the formation of two or more descendant species from a single ancestral species all occupying the same geographic location.

Often-cited examples of sympatric speciation are found in insects that become dependent on different host plants in the same area.[10][11] However, the existence of sympatric speciation as a mechanism of speciation is still hotly contested. Scientists have argued that the evidences of sympatric speciation are in fact examples of micro-allopatric, or heteropatric speciation.[citation needed]

The best illustrated example of sympatric speciation is that of the cichlids of East Africa inhabiting the Rift Valley lakes, particularly Lake Victoria, Lake Malawi and Lake Tanganyika. There are over 800 described species, and according to estimate, there could be well over 1,600 species in the region. All the species have diversified from a common ancestral fish (Oryzias latipes) about 113 million years ago. Their evolution is cited as an example of both natural and sexual selection.[12][13]

Until recently,[when?] there has been a dearth of strong evidence that supports this form of speciation, with a general feeling that interbreeding would soon eliminate any genetic differences that might appear. But there has been at least one study, in 2008, that suggests that sympatric speciation has occurred in Tennessee cave salamanders.[14]

Sympatric speciation driven by ecological factors may also account for the extraordinary diversity of crustaceans living in the depths of Siberia's Lake Baikal. Source of the article published in description is Wikipedia. I am sharing their material. Copyright by original content developers of Wikipedia.
Link- http://en.wikipedia.org/wiki/Main_Page