Human Population Growth

1. Human Population Growth Miller Chapter 11-1

2. Factors affecting population size • Populations grow or decline through the interplay of three factors • Births • Deaths • Migration • Immigration • Emigration

3. Migration • Emigration – moving away from a population • Begins with “E” like exit • Immigration – moving into a population • Begins with “I” like into

4. Population change • Population change = (Births + immigration) – (Deaths + emigration) When these balance – ZPG (Zero population growth)

5. Birth and death rates • Calculated as the number of births or deaths per 1000 people in a population in a given year.

7. Annual percent population change

8. Fertility Rates • Replacement fertility – number of children needed to replace themselves 2.1 to 2.5 per couple.

9. Replacement Fertility Rates

10. Total Fertility Rate (TFR) • Estimate of average number of children a woman will have between ages 15-49 • Current world value of 2.9 would result in a world population of 296 billion in 150 years

12. Fertility Rates US • US population has increased from 76 million in 1900 to over 276 million. • Our fertility rates have dropped since 1950, but we continue to grow very rapidly.

14. Factors that affect Birth and Fertility rates • Importance of children in the workforce • Urbanization • Cost of raising and educating children • Educational and employment opportunities for women • Increases • Decreases – access to family planning • Decreases • Decreases

15. Infant mortality rate • Average age of marriage or first child • Availability of legal abortions • Increases with increasing mortality • Increases with lower age • decreases

16. Availability of reliable birth control • Religious beliefs, traditions, and cultural norms • Decreases • Increases in countries where large families are encouraged