A typical population growth curve (number of individuals x time, linear scale) has a sigmoidal shape. There is a short and slow initial growth followed by a fast and longer growth and again a decrease in growth preceding the stabilization or equilibrium stage.
The population growth according to the biotic potential curve however is not sigmoidal, it is only crescent-shaped and points up to the infinite value of the scale (there is neither a decreasing stage nor equilibrium).