Studying Human Populations The Human Population Studying Human Populations

The Human Population Over Time Demography- The study of populations Most often human pop. Study historical size and makeup Human pop. Had slow growth until 1800s Underwent exponential growth Industrial and scientific revolutions

World Population Over Time

Forecasting Population Size Age structure- The distribution of ages in a specific population at a certain time Population pyramid- Double-sided bar graph to illustrate age structure

Forecasting Population Size Survivorship- The percentage of members of a group that are likely to survive at any given age. Survivorship curves- Graphs of survivorships

Forecasting Population Size Fertility rates- The number of babies born each year per 1,000 women in a population Declines with increased education and economic independence for women 1.6 children per woman in developed countries 3.1 children per woman in developing countries Replacement level- Number of children a woman must have in order to “replace” themselves

Forecasting Population Size Migration- The movement of individuals between areas. Immigration- Movement into an area Emigration- Movement out of an area

Declining Death Rates Life expectancy- The average number of years a person is expected to live. Most affected by infant mortality (death rate of infants under 1 year)

The Demographic Transition Model that describes population growth changes. Based on observations of history Compares birth rates, death rates and population size Stages of the transition: Stage 1- Preindustrial Stage 2- Transitional Stage 3- Industrial Stage 4- Postindustrial

The Demographic Transition