AP Bio 8.4 Effect of Density on Populations

limiting factors: factors that limit population growth

• populations cannot grow indefinitely and experience limiting factors

• density-dependent limiting factors limit a population’s growth based on how many individuals there are in a certain area (population density)

• density-independent limiting factors limit population growth no matter how dense a population is

• limiting factors result in a carrying capacity

  • carrying capacity: the sustainable number of a population that can be supported by the ecosystem’s total available resources

  • as a population’s size approaches carrying capacity, it exhibits logistic growth

    • exponential growth and then plateaus as it approaches carrying capacity

    • \frac{dN}{\differentialD t}=r_{\max}N\left(\frac{K-N}{K}\right)

      • dN = change in population size

        • N = population size

      • dt = change in time

      • dN/dt = population growth rate

      • K = carrying capacity