Population Pyramids

1
Population Pyramids

• Investigating Population Pyramids and what they
  tell us.
• AP Human Geography

2
What are Population Structures and Population
Pyramids?
A Population Structure is the composition of a
population, the most important elements of which
are age and sex Population Pyramids are bar
charts, arranged vertically that shows the
distribution of a population by age and gender.
Source US Census Bureau International Data Base
3
Take a couple minutes to study this pyramid. Jot
down things you can tell about this countrys
population.
4
Useful tips for understanding population pyramids

• Divide the Pyramid into 3 sections
• The young dependent population
• The economically active population
• The elderly dependent population

Retired Dependents
Retired Dependents
Workforce
Workforce
Child Dependents
Child Dependents
5
Why are population Pyramids Useful?

• The Pyramid contains information about
• Genders
• Population of Specific Ages
• Life Expectancy
• Death Rate
• Birth Rate
• Infant Mortality
• Population of the workforce
• Population of dependents
• How the Population changes

6
How Pyramids Are Used

• Migration Patterns
• Identify Areas where there are ageing populations
  or young population profiles
• Illustrate Development Indicators like Birth
  Rate.

• Predictive tools for future services likes
  schools, nursing homes, pension programs, health
  services
• Calculate Dependency Ratios
• Government Policy pronatalist or antinatalist

• -

7
Four Basic Pyramid Shapes

• Early Expanding

• Late Expanding

Stationary
Contracting
Source US Census Bureau International Data Base
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Early Expanding

• Wide Base (High Birth Rate)
• Rapidly Tapers (High Death Rate)
• Short bars in Higher age groups (Low Life
  Expectancy)

Source US Census Bureau International Data Base
9
Late Expanding

• Beehive in Shape
• Less Tapering (Falling Death Rate)
• Base less wide (Falling Birth Rates
• Improving Life Expectancy

Source US Census Bureau International Data Base
10
Stationary

• Bars change little from generation to generation
  (low Death Rate)
• Improving Life Expectancy
• Births around replacement level

Source US Census Bureau International Data Base
11
Contracting

• Coffin Shape
• Short Base Bars as Birth Rate is well below
  replacement
• Long bars in older generations (Ageing
  Population)
• Long Life Expectancy

Source US Census Bureau International Data Base
12
How do pyramids connect to Demographic Transition
Model?
13

Demographic Transition Model
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3
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Population Structures Differences among Countries

• Differences in population structures can be based
  on one or more of the following
• Migration (in and out, urban/rural)
• Sex Ratio
• Access to health services (both young and old)

15
Sex Ratio

• Sex Ratio is the number of males per 100 females
  in a population.
• Male births consistently exceed female births due
  to a combination of biological and social reasons
  (infanticide- a phenomenon we will discuss in the
  next unit)

16
Population Projections

• Populations projections are the prediction of
  future populations based on the present
  age-gender structure, and with present rates of
  fertility, mortality and migration.
• Population projections are always hypothetical in
  nature.