Explain the process of evolution through isolation that results in speciation

the speciation, or a divergence of the population into a separate species, will can take two forms: allopatric, where a physical barrier seperates populations (darwin's finches), also the sympatric, where the  population sharing the geographic location is forced by a environmental factors to diverge. once they have diverged, either prezygotic or postzygotic barriers can prevent interbreeding between the two species. prezygotic barriers.
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