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Unformatted text preview: Speciation can occur with little or no anatomical change in organisms. If the organisms do not reproduce, they are biologically different species. Similarly, change in appearance within a species is a natural process and may not lead to speciation in the absence of any isolating factors. Such isolation factors can be random events or the result of natural selection. Maintaining Reproductive Isolation Ultimately in order for new species to form, the separation of gene pools by geography, ecology, genetics or behavior, must be accompanied by or followed by reproductive barrier so that interbreeding is not possible, even if the gene pools were to be mixed again. Reproductive isolating mechanisms may prevent successful fertilization (pre-zygotic or pre-mating) or successful development (post-zygotic or post-mating). The isolation mechanisms just discussed of geography, time, behavior and structure are pre-zygotic reproductive mechanisms....
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- Spring '10