POPULATION GROWTH CURVES

Exponential Growth Exponential growth represents growth of organisms who have an unlimited supply of food and all limiting factors have been removed. The carrying capacity (K) of the ecosystem is assumed to be unlimited. It is a J – shaped curve. The steepness of the J varies with species.

Exponential Growth Example: bacteria Example: bacteria Number of individuals (N) Time J-shaped produces a J-shaped curve

Logistic Growth Logistic Growth - Growth rates are regulated by internal and external factors until they come into equilibrium with environmental resources. Growth rate slows as population approaches carrying capacity. S-Shaped curve Environmental Resistance - Any environmental factor that reduces population growth.

Logistic Growth Example: turtles in a pond Example: turtles in a pond Number of individuals (N) Time S-shaped produces a S-shaped curve K