An example of reproductive isolation results from differences in the mating season is that of the two toad species, the American toad (Anaxyrus americanus) and Fowler's toad (Bufo fowleri). Despite their overlapping geographic range―both are found in the eastern United States and Canada―and the fact that they have been successfully bred in laboratories to produce fertile offspring, they are not known to mate in the wild because the American toad mates in early summer, while the Fowler's toad mates in late summer. a) What type of reproductive isolation is this an example of? Explain your answer.

b) Suppose that the Fowler toad mates in late summer because it is warmer in late summer. What might happen to these two populations if temperatures continue to increase?