Question

Name the four factors that affect population growth. Then, explain how each factor contributes to population growth.

Answer 1

The four main factors that affect population growth are: birth rate (natality), death rate (mortality), immigration, and emigration.

- Birth rate (natality): the number of births in a population per unit time. Higher birth rates add people and increase population size; lower birth rates slow growth or can lead to decline. Birth rate is influenced by fertility (average children per woman), cultural norms, access to contraception, economic conditions, and government policies.

- Death rate (mortality): the number of deaths in a population per unit time. Higher death rates reduce population size; lower death rates (from better healthcare, nutrition, sanitation, and safety) increase population by allowing more people to survive to reproductive age and beyond.

- Immigration: the number of people moving into a population from elsewhere. Immigration raises population size directly and can change age structure (for example, bringing working-age people), which can further affect future growth through higher birth rates.

- Emigration: the number of people leaving a population to live elsewhere. Emigration lowers population size and can reduce future growth, especially if large numbers of reproductive-age people or skilled workers leave.

Population change = (births − deaths) + (immigrants − emigrants). Each factor’s magnitude and interactions (e.g., declining death rates with sustained high birth rates) determine whether a population grows, stabilizes, or shrinks.