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Investigating Population Pyramids and what they tell us. AP Human Geography
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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.
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Take a couple minutes to study this pyramid. Jot down things you can tell about this country’s population.
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Retired Dependents Workforce Child Dependents Divide the Pyramid into 3 sections: The young dependent population The economically active population The elderly dependent population
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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?
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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
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Early ExpandingLate Expanding StationaryContracting Source US Census Bureau International Data Base
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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
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Beehive in Shape Less Tapering (Falling Death Rate) Base less wide (Falling Birth Rates Improving Life Expectancy Source US Census Bureau International Data Base
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Bars change little from generation to generation (low Death Rate) Improving Life Expectancy Births around replacement level Source US Census Bureau International Data Base
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‘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
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How do pyramids connect to Demographic Transition Model?
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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)
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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)
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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.
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