1. Chap. 9: The Human Population Sect
Chap. 9: The Human Population Sect. 1: Studying Human Populations Key Vocabulary
Demography & Demographers
Developed vs. Developing Countries
Age Structure & Age-Structure Diagrams
Survivorship & Survivorship Curves
Fertility Rate & Replacement Level
Migration (Immigration vs. Emigration)
Life Expectancy & Infant Mortality
Demographic Transition (Model with 4 Stages)

2. Demography
Demography is the study of the characteristics of populations, especially human populations.
Demographers study…
historical size and makeup of the populations of countries
properties that affect population growth, such as economics and social structure

3. Developed vs. Developing Countries
Developed countries
higher average incomes
slower population growth
diverse industrial economies
stronger social support systems
Ex: U.S.A., Canada, Japan
Developing countries
lower average incomes
rapid population growth
simple and agriculture-based economics
Ex: Afghanistan, Somalia, India

4. Map: Developed vs. Developing Countries

5. Map: Developed vs. Developing Countries

6. Exponential Human Population Growth
Exponential growth started in 1800s = Industrial Revolution
due mostly to increases in food production and improvements in hygiene
Problem: Earth can’t sustain this growth!!!

7. Age Structure
Age structure is the classification of members of a population into groups according to age
helps demographers make predictions
Countries that have…
…high rates of growth: have more young people than older people
…have slow growth or no growth: have an even distribution of ages in the population

8. Age-Structure Diagrams = Population Pyramids
…a type of double-sided bar graph
% of Population Males vs. Females on opposite sides
Shape of graph correlates with rate of population growth:
Developing countries = rapid growth = more young than old
Developed countries = slow growth = about equal numbers of all age groups

9. Survivorship
Survivorship is the percentage of newborn individuals in a population that can be expected to survive to a given age.
Related to life expectancy
Survivorship Curves
Type I: wealthy developed countries, most people live to old age
Type II: similar death rate at all ages
Type III: poor developing countries, most people die very young, high infant mortality rate

10. Historical graph of the U.S. Fertility Rate
Fertility rate = the number of births (usually per year) per 1,000 women of childbearing age (usually 15 to 44)
Replacement level = the average number of children each pair of parents must have in order to “replace” themselves (usually slightly more than 2)
Historical graph of the U.S. Fertility Rate

11. Historical U.S. population growth due to Immigration and Births
Migration in general, is any movement of individuals or populations from one location to another.
Immigration = movement into an area
Emigration = movement out of an area
Historical U.S. population growth due to Immigration and Births

12. Why is the world’s human population growing so rapidly?
…because death rates have declined more rapidly than birth rates
…because more people have access to adequate food, clean water, safe sewage disposal, vaccine use
This leads to…
Higher average life expectancy = the average length of time that an individual is expected to live
Lower infant mortality = the death rate of infants less than a year old

13. The Demographic Transition
The demographic transition is the general pattern of demographic change from high birth and death rates to low birth and death rates
Observed in the history of more- developed countries
Theory behind it: industrial development causes economic and social progress that then affects population growth rates

14. 4 Stages of the Demographic Transition Model
Stage 1: preindustrial society; high birth and death rates; population size is stable
Stage 2: transitional society; low death rates (improved health, etc.), still high birth rates; population grows very fast
Stage 3: industrial society; birth rates slow down, still low death rates; population size stabilizes
population is much larger than before the demographic transition
Stage 4: postindustrial society; birth rate drops below replacement level; size of the population begins to decrease
Demographic Transition takes 1-3 generations to occur

15. 4 Stages of the Demographic Transition Model

16. Women and Fertility: What causes the Demographic Transition?
The factors most clearly related to a decline in birth rates are increasing education and economic independence for women.
In the demographic transition model, the lower death rate of the second stage is usually the result of increased levels of education.
Educated women…
do not need to bear as many children to ensure that some will survive
learn family planning techniques
contribute to their family’s increasing prosperity
spend less energy bearing and caring for children