![]() Sympatric selection can also be the result of a combination of sexual selection and ecological factors. ![]() If some members are specialized to live in a given environment, that subgroup can continue to occupy a different environmental niche and eventually evolve into a new species over time. ![]() It is believed that an important factor in cases of sympatric speciation is adaptation to environmental conditions. The subgroups of species that are experiencing sympatric speciation will show few differences, since they have been diverging for a relatively short time, in relation to the time scale in which evolution occurs. Sympatric speciation has been observed in Bacillus, in bacteria species Synechococcus, in bacterioplankton Vibrio splendidus, among others. It is believed that sympatric speciation occurs more frequently in bacteria, since bacteria they can exchange genes with other individuals who are not progenitors or descendants, in a process known as horizontal gene transfer. The true examples of sympatric speciation have rarely been observed in nature. In these cases, reproductive isolation inevitably occurs, since a population of polyploid individuals can not cross a population of diploid individuals. ![]() Having more than two chromosomal games is considered a polyploidy (poly = many). However, errors in the distribution of chromosomes during cell division can occur, thus generating offspring with twice as many copies (tetraploidy). Normally individuals have two sets of chromosomes (diploidy), one from each parent. This phenomenon of speciation mediated by polyploidy occurs as follows. Therefore, the descendants live in the same environment as their parents, but they are reproductively isolated. For example, parental plants produce offspring that are polyploid. Sympatric speciation is more common in the plant world. Examples of sympatric speciation In plants Allen Orr have developed four criteria to infer whether the species have emerged sympatrically:ġ-The territories of the species must overlap significantly.Ģ-There must be complete speciation (ie, the two species can not cross and leave fertile offspring).ģ-The species must be sister species (the most related to each other) or part of a group that includes an ancestor and all its descendants.Ĥ-The history of the geographical territory and the evolution of the species should be such that alopatry seems very unlikely, since sympatric speciation is much less common than allopatric. 1 Characteristics of sympatric speciation.The first colonization led to the emergence of a species of thorny, while the other species evolved from the second colonization. However, it can be difficult to determine if the speciation that has taken place is of the sympatric type, which has led to much discussion among evolutionary biology researchers.įor example, two closely related spiny species were originally thought to evolve through sympatric speciation, but subsequent research suggests that the two different species colonized the lake independently. When two groups can no longer reproduce and leave fertile offspring, they are considered different species. Sympatric speciation is unique because it occurs while two subpopulations of the same species occupy the same territory or share overlapping territories.Īlthough the area in which the organisms live is the same, they can be divided into two different groups that eventually become so genetically different from one another that they can no longer reproduce each other. However, in nature it can be difficult to know when sympatric speciation occurs or has occurred. Sympatric speciation can be seen in many different types of organisms, including bacteria, cichlid fish and the apple worm fly. Synechococcus bacteria, in which sympatric speciation has been observedĮxamples of sympatric speciation are often debated because they must show convincing evidence that new species are descended from the same ancestral species, as well as the existence of reproductive isolation and that the cause of the emergence of the new species is not alopatry ( allopatric speciation ).
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