Although vital, replication is the most uninteresting operator: alone it contributes nothing to genetic diversification. (Indeed, replication, together with selection, is only capable of causing genetic drift.) According to fitness and the luck of the roulette, chromosomes are faithfully copied into the next generation. The fitter the individual the higher the probability of leaving more offspring. Thus, during replication the genomes of the selected individuals are copied as many times as the outcome of the roulette. The roulette is spun as many times as there are individuals in the population, always maintaining the same population size.