1. The Demographic Transition
Fig. 2-13: The demographic transition consists of four stages, which move from high birth and death rates, to declines first in death rates then in birth rates, and finally to a stage of low birth and death rates. Population growth is most rapid in the second stage.

3. Stage One
Crude birth rates (CBR) and crude death rates (CDR) varied from year to year, but over long term were at very high levels
Natural Increase Rate (NIR) was virtually zero
Hunting and gathering
Agricultural Revolution – domestication of plants and animals
Food supplies still unpredictable
No nation remains in stage one

4. Stage Two
Crude Death Rate (CDR) drops dramatically while the Crude Birth Rate (CBR) stays roughly the same – high
Natural Increase Rate (NIR) increases quickly and population grows rapidly
Two possible parts
First period has accelerated population growth
Second period has growth rate slowing, although gap between births and deaths remain high

5. Stage Two
Countries entered stage two as result of the Industrial Revolution (began in England)
Spread through Europe and North America
Major improvements in technology led to improvements in mass production, transportation, and technology
Changes led to higher levels of wealth, which led to healthier places to live
New agricultural machines meant ability to feed rapidly growing population

6. Stage Two
Improvements in agriculture freed people to work in factories – more goods for people
Wealth produced allowed improvements in sanitation and personal hygiene
Sewer systems and water supplies
People healthier and lived longer
Entering Stage Two
Europe (many) and North America about 1800
Africa, Asia, and Latin America around 1950

7. Stage Two
Medical Revolution – medical technology invented in Europe and North America diffused to less developed countries in Africa, Asia, and Latin America
Many traditional causes of death reduced
Immunizations to smallpox

8. The Demographic Transition

9. Stage Three
Country moves from stage 2 to stage 3 when CBR begins to drop sharply
CDR continues to fall, but much slower rate
Population continues to grow because CBR is still greater than CDR
NIR is less (and decreases) during stage 3
European and North American countries generally moved from stage 2 to stage 3 during the first half of twentieth century
Most of Asia and Latin America moved recently
Africa remains in stage 2

10. Stage Three Drop in CBR during stage 3 happens for different reasons
Mainly due to social customs
People choose to have fewer children
Partly a delayed reaction to decline in mortality, especially the IMR
Economic changes also play a role
People more likely to live in urban areas (cities) and work in factories, offices, or shops (not farms)
Unlike farmers, children in urban areas not seen as assets

11. Stage Four
Country reaches stage four when zero population growth (ZPG) is obtained
Occurs when CBR declines to the point it slightly higher than the CDR and the NIR approaches zero
Some females die before reaching childbearing years
Demographers define ZPG as the TFR that results in a lack of change in the total population over a long term
TFR of 2.1 produces ZPG
Country with many immigrants may need to lower TFR to achieve ZPG

12. Stage Four Most European countries have reached stage 4
Social customs explain movement from stage 3 to stage 4
Women entering the labor force – no longer being homemakers
Changes in lifestyle also explain movement
Birth-control (wider variety and more likelihood)
Increased leisure time for people to participate in recreation activities not suitable for children

13. Stage Four
Several Eastern European countries have negative NIRs (more deaths than births)
Reasons include Communist rule, inadequate pollution controls, strong family-planning programs, and deep-seated pessimism about having children in an uncertain world
Changing now that communism is gone

14. The Demographic Transition

15. Population Pyramids
Displays a country’s population by age and gender on a bar graph
Important to study as population in a country is influenced by the percentage of the population in each age group and the distribution of males and females
Length of bar represents percentage of total population in that group
Shape of pyramid determined by the CBR
Examine shape of pyramid by stage in demographic transition

16. Population Pyramids Age Distribution
Dependency Ratio – number of people who are too young or too old to work, compared to the number of people in their productive years
Larger percentage of dependents leads to increased financial burden on those trying to support
Three age groups used for comparison
0 to 14, 15 to 64, 65 and older
0 to 14 and 65 and older are considered dependents

17. Population Pyramids Age Distribution
Dependency Ratio
1/2 of people in stage 2 are dependents, while only 1/3 of people in stage 4 are dependents
Dependency ratio is 1:1 in stage 2 and 1:2 in stage 4
Large percentage (15%) of children in sub-Saharan Africa and other stage 2 countries strains ability of poor countries to provide needed services
Schools, hospitals, and day-care centers

18. Population Pyramids Age Distribution
Higher population of elderly in later stages of demographic transition
Older people benefit from improved medical care and higher incomes
Larger percentage of elderly puts strain on the governments to meet needs of “greying” population
1/4 of government expenditures in U.S., Canada, and Japan go to programs for older population

19. Percent of Population under 15
Fig. 2-15: About one-third of world population is under 15, but the percentage by country varies from over 40% in most of Africa and some Asian countries, to under 20% in much of Europe.

20. Population Pyramids
Sex Ratio – number of males per hundred females in the population
Generally, more males than females are born, but males have higher death rates
Europe and North America 95:100
Rest of world ration is 102:100
Poor countries – higher mortality rate during childbirth explains lower percentage of women

21. Different Stages of Demographic Transition: Rapid Growth in Cape Verde
Fig. 2-17: Cape Verde, which entered stage 2 of the demographic transition in about 1950, is experiencing rapid population growth. Its population history reflects the impacts of famines and out-migration.

22. Different Stages of Demographic Transition: Moderate Growth in Chile
Fig. 2-18: Chile entered stage 2 of the demographic transition in the 1930s, and it entered stage 3 in the 1960s.

23. Different Stages of Demographic Transition: Low Growth in Denmark
Fig. 2-19: Denmark has been in stage 4 of the demographic transition since the 1970s, with little population growth since then. Its population pyramid shows increasing numbers of elderly and few children.

26. USA

34. Figure: 02-16
Title:
Population pyramids for the United States and selected communities.
Caption:
Detroit and Laredo have broader pyramids than Cedar Rapids and Honolulu, indicating higher percentages of young people and higher fertility rates. Unalaska has a high percentage of males because it contains an isolated military base. Lawrence has a high percentage of people in their twenties because it is the home of the University of Kansas. Naples has a high percentage of elderly people, especially women, so its pyramid is upside down.