Do Now: Population Pyramids Movie Clip
• Answer the following:
1) What is a population pyramid?
2) How do they differ for developed and less developed
countries?
Aim: Why does population composition
matter?
Population Composition
Population Composition is concerned with:
• Gender distribution
• Age distribution
within a country, region, or place.
A Population’s Age Structure Helps Us
Make Projections
• Age structure categories
• Prereproductive ages (0-14)
• Reproductive ages (15-44)
• Postreproductive ages (45 and older)
• Seniors are the fastest-growing age group
Population Pyramids –
Charts that show the percentages of each age group in the total
population, divided by gender.
For poorer countries, the chart is shaped like a pyramid.
Infant mortality rates are high, life expectancy is shorter.
Generalized Population Age-Structure Diagrams
Fig. 6-12, p. 136
Population Structure by Age and Sex in Developing and
Developed Countries
Fig. 6-13, p. 136
Pause…Think…Discuss…
• If all the girls under 15 were to have only one child during
their lifetimes, how do you think these structures would
change over time?
In poorer countries, Infant Mortality Rates are
usually high, which is reflected in the pyramid shape.
In poorer countries, Life Expectancy is usually
shorter, which is also reflected in the pyramid shape.
Affect of AIDS on
population pyramid
for South Africa.
Predicted population for
2035, without and with AIDS.
With AIDS, looks like a
population “chimney.”
Botswana Age Structure, With and Without AIDS
Fig. 6-16, p. 139
Pause…Think…Write
• How might this affect Botswana’s economic development?
Do you understand how to read an age
structure graph?
Read A- Loud
• Case Study: The American baby boom
Population Pyramids –
Charts that show the percentages of each age group in the total
population, divided by gender.
For wealthier countries, the chart is shaped like a lopsided
vase. Population is aging, TFRs are declining.
Age Structure of a Population
• The populations of many countries are aging.
- eg. Europe
- eg. Japan
Bordeaux, France
Aging Populations
• To replace the population, TFR must be 2.1.
-
TFR in Bologna, Italy is 0.8
Why are women having fewer children?
• What are the impacts of an aging population on a
country?
• What are the “solutions” to an aging population?
Case Study: The American Baby Boom
• 79 million people, 36% of adults
• Affect politics and economics
• Now becoming senior citizens
• Graying of America
Tracking the Baby-Boom Generation in the United States
Fig. 6-14, p. 137
Populations Made Up of Mostly Older
People Can Decline Rapidly
• Slow decline
• Manageable
• Rapid decline
• Severe economic problems
• How pay for services for elderly
• Proportionally fewer young people working
• Labor shortages
• Severe social problems
Some Problems with Rapid Population Decline
Which three of these
Problems do you
Think are the most
Important and why?
Populations Can Decline from a Rising
Death Rate: The AIDS Tragedy
• 27 million killed: 1981-2009
• Many young adults die: loss of most productive workers
• Sharp drop in life expectancy
• International community
• Reduce the spread of HIV through education and health care
• Financial assistance and volunteers
Do you understand how an older
population negatively impacts a country?
Summary:
• In terms of TFR and birth and death rates, explain what is
happening in each age structure pyramid.
Thinking Geographically
• In the United States, the national infant mortality rate
(IMR) is 7.0. That number represents an average for the
country. Think about the differences in IMR in the United
States across regions, ethnicities, social classes, and
other sectors.