What effect does the number of species with only one individual, f1,f1, have on the estimate of the total number of species? As both f1f1 and f2f2 increase, the estimate of species number also increases. As f1f1 increases, the estimate of species number decreases. As f1f1 increases, the estimate of species number also increases, except when f1f1 is between the values of zero and one. The value of f2f2 has a much greater influence on the estimate of species number than the value of f1.f1.