1. Chapter 9 Section 1: Studying Human Populations

2. Demography  Demography  The study of populations.  Demographers have grouped countries into two groups:  Developed Countries  Higher AVG Income, slow population growth  Developing Countries  Lower AVG Income, rapid population growth

3. The Human Population Over Time  The human population has grown exponentially over the past 150+ years.  Scientists predict that the Earth can not sustain this kind of population increase at the current standards of living.

4. Forecasting Population Size Demographers will look at these properties to predict future population size.

5. Age Structure  Age Structure  The distribution of ages in a specific population at a specific time.  Usually represented in a population pyramid. This graph shows the age structure of the country.

6. Survivorship  Survivorship  The percentage of members in a group that are likely to survive at a given age. Shown in a Survivorship Curve  Type I Curve  Individuals live to advanced age  Type II Curve  All ages have similar death rate  Type III Curve  Many offspring die young.

7. Fertility Rate  Fertility Rate  The AVG number of children a woman gives birth to in her lifetime.  The Replacement Level fertility rate is about 2.1.  This is the fertility rate needed in order for parents to replace themselves in the population.

8. Migration  Migration  The movement of individuals from one place to another.  Movement into an area is called immigration.  The U.S. fertility rate has been below replacement levels for several years, but the U.S. population continues to grow due to immigration.

9. Declining Death Rates The dramatic increase in population is due mainly to the decline of death rates.

10. Declining Death Rate  Reasons for the decline:  Better access to  food  clean water  sewage disposal.  Discovery of vaccines.

11. Life Expectancy  Life Expectancy  The average number of years members of a population are likely to live  L.E. is most affected by infant mortality rates. L.E. goes up when infant mortality is low.  L.E. has gone up consistently since 1900.

12. Life Expectancy

13. Demographic Transition  Demographic Transition  A model that describes how economic and social changes affect population growth rates.  Shows how populations go through stages of population growth, maintenance, and decline.

14. Women and Fertility  When populations reach the final stage of demographic transition, the population declines.  The factor most clearly related to a decline in birth rate is the education of women.