Figure 6: Sketch to construct the cut-off condition in the case of initial form and one kind of mutant . If, by multiplication of individuals (black disk •) with factors and respectively, the total number would be beyond the limit of supply , (circle ∘), the correct cut-off point (black square ■) is the most adjacent to the intersection. Note: partition and take average for more than one such point. The probability distributions and cut-off conditions in the cases of more than one kind of mutant are accordingly.