Studying Human Populations Section 9.1 Objectives: 1. 1.Define four properties used by scientists to predict population sizes Make predictions about population trends based on age structure Describe the four stages of the demographic transition.

World Population Over Time Chapter 9 Hypothesize WHY the population has recently grown so rapidly.

Demography “demos” means “people” Definition: the study of populations

Forecasting Population Size Why would it be important to accurately predict human population changes? Predictions are based on: 1. 1.Age structure: the distribution of ages in a specific population at a certain time 2. 2.Survivorship: the % of members of a group that are likely to survive to any given age 3. 3.Fertility rates: the number of babies born each year per 1000 women in a population 4. 4.Migration: the movement of individuals between areas

Age Structure Diagrams (p.220) Rapid growth would occur in __________ countries. How would a graph for a zero-growth population differ from a graph for a declining-growth population?

Survivorship Curves (p.220) To predict survivorship, a demographer studies a group of people born at the same time and notes when each member of the group dies.

Fertility Rates (p.221) What do you think “replacement level” means? Why is replacement level more than 2?

Migration Immigration – movement into an area Emigration – movement out of an area

Declining Death Rates In the last 200 years, death rates have declined more rapidly than birth rates. WHY? Life expectancy: Definition: the average number of years a person is likely to live Higher (longer) in developed countries

The Demographic Transition Definition: the general pattern of demographic change from high birth and death rates to low birth and death rates, as observed in the history of more- developed countries

Stages of Demographic Transition 1. 1.Preindustrial condition High birth and death rates Population size stable 2. 2.Transitional - population explosion! Death rates decline (better hygiene, nutrition, and education) Birth rates remain high 3. 3.Industrial Growth slows Birth rate decreases 4. 4.Postindustrial Population declines Birth rate drops below replacement level

Assignment # Duplicate Figure 4 (p.221) on graph paper. Label each of the different stages of demographic transition Which age structure diagram (Figure 2, p.220) corresponds to each of the transition stages on your graph? 3. 3.What do YOU think will happen in the next phase of our country’s population growth rate? Explain your reasoning.