Biology 1001A Chapter Notes - Chapter 19.3: Reproductive Isolation, Macroevolution, Zygote
Document Summary
Reproductive isolation is central to the biological species concept. A reproductive isolating mechanisms is any biological characteristic that prevents the gene pools of two species from mixing. Biologists classify reproductive isolating mechanisms into two categories: prezygotic isolating mechanisms, which exert their effects before the production of a zygote, and postzygotic isolating mechanisms, which operate after zygote formation. These isolating mechanisms are not mutually exclusive; two or more of them may operate simulataneously. There are 5 mechanisms that can prevent interspecific matings or fertilizations and therefor prevent the production of hybrid offspring => ecological, temporal, behavioural, mechanical and gametic isolation. Species living in the same geographical region may experience ecological isolation if they live in different habitats. Species living in the same habitat can experience temporal isolation if they mate at different times of day or different times of year. Many animals rely on specific signals, which may differ dramatically between species, to identify the species of a potential mate.
