In 1950s, Haldane calculated the maximum rate of genetic change due to
differential survival. His calculations reveal that many higher
vertebrate species could not plausibly evolve in the available time,
because the reproductive capacity of the species limits the rate at
which new rare traits can replace old prevalent traits. Haldane
calculated that on average, the cost of substitution is 30, and is paid
off in installments of 0.1 per generation. Thus it takes about 300
generations to pay for the cost of substituting one trait.