Investigating Population Pyramids and what they tell us.

AP Human Geography

Source US Census Bureau International Data Base

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.

Take a couple minutes to study this pyramid. Jot down things you can tell about this country’s population.

Retired Dependents

Retired Dependents

Workforce Workforce

Child Dependents

Child Dependents

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

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

Why are population Pyramids Useful?

• 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

Early Expanding Late Expanding

Stationary ContractingSource US Census Bureau International Data Base

• 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

• Beehive in Shape• Less Tapering (Falling

Death Rate)• Base less wide (Falling

Birth Rates• Improving Life

Expectancy

Source US Census Bureau International Data Base

• Bars change little from generation to generation (low Death Rate)

• Improving Life Expectancy

• Births around replacement level

Source US Census Bureau International Data Base

• ‘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

How do pyramids connect to Demographic Transition Model?

1 2 3 4 5

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)

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)

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.