Search results
Results from the WOW.Com Content Network
A large variety of mechanisms have been demonstrated to reinforce reproductive isolation between closely related plant species that either historically lived or currently live in sympatry. This phenomenon is driven by strong selection against hybrids, typically resulting from instances in which hybrids suffer reduced fitness.
Costus plants: Costus allenii, C. laevis, and C. guanaiensis; [62] [63] C. pulverulentus and C. scaber [64] A unique case of post-zygotic instead of prezygotic isolation has been observed in both Gossypium and Gilia, suggesting that in plants, post-zygotic isolation's role in reinforcement may play a larger role. [3]: 361
Increased prezygotic isolation, which is associated with reproductive character displacement, has been observed in cicadas of genus Magicicada, stickleback fish, and the flowering plants of the genus Phlox.
It is possible that the pattern of enhanced isolation could simply be a temporary outcome of secondary contact where two allopatric species already have a varying range of prezygotic isolation: with some exhibiting more than others. [42] Those that have weaker prezygotic isolation will eventually fuse, losing their distinctiveness. [7]
species differences may be caused by geographic isolation; the species may or may not occupy different habitats if they existed in sympatry; in cases of similar habitats in allopatry, species may be adapted to unknown ecological factors; if the species existed in sympatry, competition may drive habitat segregation that would be undetectable in ...
Prezygotic intrinsic and extrinsic differences have also been shown to be important in isolating hybrids from their parent species. In plants, pollinator mediated isolation resulting from changes in floral characteristics may be an important extrinsic prezygotic ecological barrier.
All three species are separated by intrinsic reproductive barriers [1] Secondary contact is the process in which two allopatrically distributed populations of a species are geographically reunited. This contact allows for the potential for the exchange of genes, dependent on how reproductively isolated the two populations have become.
Hybrid speciation is a form of speciation where hybridization between two different species leads to a new species, reproductively isolated from the parent species. Previously, reproductive isolation between two species and their parents was thought to be particularly difficult to achieve, and thus hybrid species were thought to be very rare.