A type of population growth in which the rate of increase in the number of members is proportional to the number present. Exponential growth involves an increasing rate of growth: the more individuals there are, the faster the population increases. A graph of number against time in such growth has a J-shaped curve. In practice, exponential growth does not coritinue indefinitely. Other factors (e.g. shortage of food) become important and slow down the growth rate. The resulting curve is S-shaped (sigmoid). See also

logarithmic phase.