ALLOPOLYPLOID. a fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes. HYBRID ZONE. a geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry.
in evolutionary biology, a process in which natural selection strengthens prezygotic barriers to reproduction, thus reducing the chances of hybrid formation. Such a process is likely to occur only if hybrid offspring are less fit than members of the parent species. PUNCTUATED EQUILIBRIA.
behavioral isolation. Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females.
definition of a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups. REPRODUCTIVE ISOLATION.