Evolutionists, typically atheists, insist that speciation should occur when gene-flow stops between two sub-populations due to geographic or behavioral isolation. During such isolation the gene pool of each sub-population reacts differently to the processes of [[natural selection]] and [[genetic drift]] and such evolve divergently. If this evolutionary divergence becomes great enough that crosses between individuals from different sub-populations can no longer produce viable offspring each sub-population is considered to be a new species and speciation is said to have occurred. | Evolutionists, typically atheists, insist that speciation should occur when gene-flow stops between two sub-populations due to geographic or behavioral isolation. During such isolation the gene pool of each sub-population reacts differently to the processes of [[natural selection]] and [[genetic drift]] and such evolve divergently. If this evolutionary divergence becomes great enough that crosses between individuals from different sub-populations can no longer produce viable offspring each sub-population is considered to be a new species and speciation is said to have occurred. |