Population growth

Science

Definition

Population growth describes the change in the number of individuals in a population over time. Exponential growth occurs when resources are unlimited, while logistic growth slows as the population approaches the carrying capacity of its environment.

Examples

  • Bacteria doubling every 20 minutes in a nutrient-rich petri dish (exponential)
  • Human population growing from 1 billion in 1800 to 8 billion today
  • Rabbit populations leveling off when food becomes scarce (logistic)
Key Fact

Exponential: dN/dt = rN; Logistic: dN/dt = rN((K−N)/K), where K = carrying capacity

Related Terms

Population dynamics Carrying capacity Population ecology

Study This Concept

Practice population growth with free review games in these units:

AP Environmental Science Unit 3: Populations