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Reproductive isolation. The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile.
Reinforcement, under his definition, included prezygotic divergence and complete post-zygotic isolation. [18] Servedio and Noor include any detected increase in prezygotic isolation as reinforcement, as long as it is a response to selection against mating between two different species. [4]
Isolation by distance (IBD) is a term used to refer to the accrual of local genetic variation under geographically limited dispersal. [1] The IBD model is useful for determining the distribution of gene frequencies over a geographic region. [2] Both dispersal variance and migration probabilities are variables in this model and both contribute ...
e. Reinforcement assists speciation by selecting against hybrids. Reinforcement is a process within speciation where natural selection increases the reproductive isolation between two populations of species by reducing the production of hybrids. [1][2] Evidence for speciation by reinforcement has been gathered since the 1990s, and along with ...
Prezygotic incompatibilities - reproductive barrier acting before fertilization. For example, pollinator isolation, mechanical barriers preventing mating, and sperm/ovule incompatibilities that prevent fertilization. Reproductive isolation - the presence of barriers to successful crossbreeding. Barriers can be classified in a number of ways ...
Syntopy is a special case of sympatry. It means the joint occurrence of two species in the same habitat at the same time. Just as the broader term sympatry, "syntopy" is used especially for close species that might hybridise or even be sister species. Sympatric species occur together in the same region, but do not necessarily share the same ...
Hybrid inviability is a post-zygotic barrier, which reduces a hybrid 's capacity to mature into a healthy, fit adult. [1] The relatively low health of these hybrids relative to pure-breed individuals prevents gene flow between species. Thus, hybrid inviability acts as an isolating mechanism, limiting hybridization and allowing for the ...
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. There are several primary outcomes of secondary contact: extinction of one ...