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All forms of natural speciation have taken place over the course of evolution; however, debate persists as to the relative importance of each mechanism in driving biodiversity. [ 26 ] One example of natural speciation is the diversity of the three-spined stickleback , a marine fish that, after the last glacial period , has undergone speciation ...
A prerequisite for natural selection to result in adaptive evolution, novel traits and speciation is the presence of heritable genetic variation that results in fitness differences. Genetic variation is the result of mutations, genetic recombinations and alterations in the karyotype (the number, shape, size and internal arrangement of the ...
In this theory, speciation and rapid evolution are linked, with natural selection and genetic drift acting most strongly on organisms undergoing speciation in novel habitats or small populations. As a result, the periods of stasis in the fossil record correspond to the parental population and the organisms undergoing speciation and rapid ...
Evolutionary biology is the subfield of biology that studies the evolutionary processes such as natural selection, common descent, and speciation that produced the diversity of life on Earth.
In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. [1] An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation .
Speciation is the process in which populations within one species change to an extent at which they become reproductively isolated, that is, they cannot interbreed anymore. However, this classical concept has been challenged and more recently, a phylogenetic or evolutionary species concept has been adopted.
This process of speciation influenced by natural selection is reinforcement, and can happen under any mode of speciation [3]: 355 (e.g. geographic modes of speciation or ecological speciation [21]). It necessitates two forces of evolution that act on mate choice: natural selection and gene flow. [22]
Geographic and natural elements may likewise add to these cycles and lead to examples of hereditary variety, such as genetic differences that cause genetic isolation. [3] Genetic variations are often unequally distributed over a species' geographic distribution, with differences between populations at the geographic center and the range's ...