nBut for transitions
across the upper levels of the biological classification
system, many mutations would be needed, probably
100s or 1000s.
nThe chance of getting
5 (or 10) mutations of the right sort in a population
varies with the 5th (or 10th) power of the population size, so large populations are heavily
favored.
nThis more than
cancels out the benefit of a small population.