19.1 On the Road To Speciation
Species means "kind," as in "a particular kind of duck."
Through the history of any species, micro evolutionary processes have been introducing changes in the gene pools of its populations. Remember, particular alleles give rise to the heritable traits of populations. As an outcome of mutation, genetic drift, gene flow, and natural selection, different alleles can increase or decrease in frequency, or even disappear over time.
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