There are three types of population pyramids: expansive, slow growth, and no growth. A population pyramid graphically represents the age and sex composition of a population based on census data. Pyramid A represents a developing country with a high and increasing birth rate seen in its large 0-4 age group. Pyramid B shows a developed country with a decreasing birth rate seen by comparing age groups. Pyramid C has a birth rate that is neither increasing nor decreasing significantly.

1. Population pyramid
(Population & Demography)

2. 3 types
• Expansive (broad-based)
• Slow growth
• No growth (stationary)

4. Found in pyramids
• Sex information obtained from a census.
• A population pyramid is a graphical representation of the
composition of aa given population.

5. Pyramid A
• This pyramid represents a country with an increasing birth rate.
• This can be seen because the 0-4 year age group has a larger
population than any of the other age groups.
• This characteristic of a high birth rate is common to developing
countries such as the Caribbean.

7. Pyramid B
• Represents a country where the birth rate is decreasing.
• This inference can be drawn by comparing the 0-4 year age group
with the other age groups just above it.
• A deceasing birth rate is characteristic of most developed countries.
• Such countries sometimes depend upon immigrants to fully utilise
their physical resources.

9. Pyramid C
• This pyramid represents a situation where the birth rate is neither
increasing nor decreasing significantly.
• The birth rate over the years is nearly constant.

11. Notes
• It will be seen that Pyramid A (developing countries with high birth
rate) has smaller percentages of population in these age groups than
Pyramids B and C.
• It is the responsibility of governments to make special provisions for
the aged.
• Governments of developed countries, where there is a higher
standard of living, have a larger population in these age groupsto
cater for than developing countries.

12. GLOSSARY
• Crude Birth Rate: the number of live births per 1000 persons in a population
within a given period of time, usually one year.
• Crude Death Rate: The number of deaths per 1000 persons occurring within a
period of a year in a particular population.
• Natural increase: The increase in population brought about when the birth rate
exceeds the death rate.
• Infant Mortality Rate: the annual number of deaths per 1,000 infants (under
the age of 1) in the population.
• Life Expectancy: the average number of years that persons in a given
population are expected to live.

13. Factors affecting Life Expectancy
• Diet an nutrition
• Availability and cost of medical care
• Health and sanitation levels
• Availability of jobs and the dependency ratio
• Stress levels
• Levels of wages/salary