How is the population growth rate calculated?
Many factors determine a population’s growth rate. The essential tools for determining how fast a population grows, however, can be narrowed to a few key equations.Intrinsic Growth RateThe growth rate of a population, where the population’s previous size and present size are known, is called the intrinsic growth rate and can be calculated using the following equation: r = N(t) — N(t-1)/N(t-1), where N(t) is the size of a population after t units of time.Exponential GrowthIt is important to note that the growth rate is dependent on the size of a population. This relationship is referred to as exponential growth, meaning that as the size of a population increases, the rate at which it grows increases as well.Using the Exponential Growth RateThe exponential growth rate (r) is used to calculate a future population size through the following equation: N(t) = N(0)e^rt, where N(0) is the original size of the population and e is the constant logarithmic base with an approximate value of 2.72.
