Reproductive Isolation
The mechanisms of reproductive isolation or hybridization barriers are a collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced is not fertile. These barriers maintain the integrity of a species over time, reducing or directly impeding gene flow between individuals of different species, allowing the conservation of each species’ characteristics.
The mechanisms of reproductive isolation have been classified in a number of ways. Zoologist Ernst Mayr classified the mechanisms of reproductive isolation in two broad categories: those that act before fertilization (or before mating in the case of animals, which are called pre-copulatory) and those that act after. These have also been termed pre-zygotic and post-zygotic mechanisms. The different mechanisms of reproductive isolation are genetically controlled and it has been demonstrated experimentally that they can evolve in species whose geographic distribution overlaps (sympatric speciation) or as the result of adaptive divergence that accompanies allopatric speciation.
Read more about Reproductive Isolation: Isolation Mechanisms That Occur Before Breeding or Copulation (pre-zygotic Isolation), Isolation Mechanisms That Occur After Breeding or Copulation (post-zygotic Isolation), Multiple Mechanisms, Hybrid Gender: Haldane's Rule, Selection For Reproductive Isolation
Famous quotes containing the words reproductive and/or isolation:
“In the nineteenth century ... explanations of who and what women were focused primarily on reproductive events—marriage, children, the empty nest, menopause. You could explain what was happening in a woman’s life, it was believed, if you knew where she was in this reproductive cycle.”
—Grace Baruch (20th century)
“One who shows signs of mental aberration is, inevitably, perhaps, but cruelly, shut off from familiar, thoughtless intercourse, partly excommunicated; his isolation is unwittingly proclaimed to him on every countenance by curiosity, indifference, aversion, or pity, and in so far as he is human enough to need free and equal communication and feel the lack of it, he suffers pain and loss of a kind and degree which others can only faintly imagine, and for the most part ignore.”
—Charles Horton Cooley (1864–1929)