1. Population Pyramids

2. Purpose/Focus Understand Population Pyramids
Determine what a country’s population looks like using a population pyramid

3. How do we get information about our population?
Census data (
Every 10 years (2010 was the most recent)
The US Census calculates number of people living in a household, rent or own your residence, phone number, race, etc.
What issues might occur when we don’t have 100% participation in the US census?
Turn and talk
Nonparticipation groups include the homeless, ethnic minorities and undocumented immigrants – fear of legal implications if they participate.
Supporters of sampling tend to have more concern for the homeless and immigrants (mostly Democrats in urban areas); those who oppose sampling are most likely from small towns and rural areas where there are fewer census data errors.

4. Population Structure Key Terms:
Population Pyramid: a bar graph displaying a country’s distinctive population structure
Dependency Ratio: number of people who are too young or too old to work, compared to the number of people in their productive years
Dependents are 0 – 14 years old and over 65 years old
Sex Ratio: number of males per 100 females in the population

5. Population Pyramid
Population Pyramid: a bar graph displaying a country’s distinctive population structure

6. Population Pyramids
Shows the percentage (or number) of the total population in five-year age groups
The shape of the pyramid indicates something unique about each population.
Wide at the bottom: high birth rate
Wide at the top: older population
Wide in the middle: population with either small families or no children

7. Dependency Ratio
Dependency Ratio: number of people who are too young (0-14) or too old to work (+65), compared to the number of people in their productive years

8. Turn and talk Dependency Ratio
The larger the dependency ratio the greater the financial burden on those who are working to support the dependents.
What kinds of social issues might arise from a large number of young dependents in a region?
What issues might result from a large number of elderly dependents?
Turn and talk
Issues in sub-Saharan Africa include struggles to provide needed services like schools, hospitals and day-care centers.
Elderly populations bring about social security issues (medical care, retirement funds, etc.)

9. Sex Ratio
Sex Ratio: number of males and females per 100 persons in the population

10. Sex Ratio
Developed countries have more females than males because women live an average of 7 years longer than men.
There is a possibility in Asian countries, such as China and India, that a large number of female babies are being aborted.

11. In your notebooks, write:
USA:
Lawrence, Kansas:
Maples, Florida:
Laredo, Texas:
Working with a partner, discuss and write why you think the population pyramid looks the way it does.

12. Population Pyramids: What are they telling you?