Search results
Results from the WOW.Com Content Network
Hybrid zones can form from secondary contact. A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. . Hybrid zones can form in situ due to the evolution of a new lineage [1] [page needed] but generally they result from secondary contact of the parental forms after a period of geographic isolation, which allowed their ...
Mathematical models, laboratory studies, and observational evidence supports the existence of parapatric speciation's occurrence in nature. The qualities of parapatry imply a partial extrinsic barrier during divergence; [2] thus leading to a difficulty in determining whether this mode of speciation actually occurred, or if an alternative mode (notably, allopatric speciation) can explain the data.
A prediction of reinforcement is that assortive mating should be common in hybrid zones; a prediction that was confirmed in 19 of the 37 cases. [6] A survey of the rates of speciation in fish and their associated hybrid zones found similar patterns in sympatry, supporting the occurrence of reinforcement. [68]
It can occur across hybrid zones due to chance, selection or hybrid zone movement. [8] There is evidence that introgression is a ubiquitous phenomenon in plants and animals, [9] [10] including humans, [11] in which it may have introduced the microcephalin D allele. [12]
A hybrid zone may appear during secondary contact, meaning there would be an area where the two populations cohabitate and produce hybrids, often arranged in a cline. The width of the zone may vary from tens of meters to several hundred kilometers. A hybrid zone may be stable, or it may not.
A tension zone is a transitional zone between two distinctive zones, the zones may be influenced by climatic factors, [1] [2] and geological variation. [ 3 ] creating a floristic tension zone. [ 4 ] A marine tension zone may be affected by variables such as depth, climate or salinity. [ 5 ]
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Genes that are incompatible according to the Dobzhansky–Muller model require three criteria. 1. The gene reduces the fitness of the hybrid, 2. The gene has functionally diverged in each of the hybridising species and, 3. The hybrid incompatibility is only present in combination with a partner gene. [6]