Answer This Question:The political cartoon depicts

population growth over the past two thousand years.

Which statement best describes this illustration?

a. Human population has decreased gradually since 1800.

b. Human population has increased gradually since 1800.

c. Human population has decreased rapidly since 1800.

d. Human population has increased rapidly since 1800.

Essential Question

•How do you interpret a

population pyramid?

What is a population Pyramid?

A population pyramid is a visual representation of the population of a country. • It is a vertical bar graph that displays a population's

age and gender composition.• It shows numbers or proportions of males and

females in each age group. • It reflects a country’s birthrate and death rate &

tells whether or not a population is growing. • This info helps us determine whether nations are

MEDCs or LEDCs

Why else are Population Pyramids Useful?

• They can show trends in the birth rate, death rate, infant mortality rate and life expectancy • These trends can help a country to plan its future

services, e.g. more homes for the elderly if there is an ageing population or fewer schools if there is a declining birth rate.• The effects of people migrating into or out of a

region or country.• The proportion of the population who are

economically active and the proportion who are dependent upon them (dependency ratio).

Dependents vs Economically Active Citizens• There are two groups of dependants; young

dependants (aged below 15) and elderly dependants (aged over 65).

• Those of working age are classed as economically active. Dependants rely upon the economically active for economic support.

• Many LEDCs have a high number of young dependants, whilst many MEDCs have a growing number of elderly dependants.

POPULATION STRUCTUREThe population pyramid displays the age

and gender structure of a country or given area

Population inFive Year

Age bands

Usually, but not always,Given in a percentage to make for easier

comparisonsbetween countries

FEMALESTo the rightMALES

To the left

Population pyramid of a less developed nation

Population Pyramid of Nigeria (1995)

Interpreting Population Pyramids

A TRIANGLE SHAPED POPULATION PYRAMID MEANS:

•Birth rate is high and Death rate is high

• High Infant mortality rate

•Low Gross Domestic Product

•Low quality of life, such as little medical care, inadequate food supply or poor water quality.

Population pyramid of a developed nation

Population Pyramid of Sweden (1995)

Interpreting Population Pyramids

A BARRELL SHAPED POPULATION

PYRAMID MEANS:

•BIRTH RATE IS LOW AND DEATH RATE IS LOW

•Low infant mortality rate & high life expectancy

•High GDP

•High quality of life, such as access to health care, plentiful food supply and good water quality

How Do Population Pyramids Change?

• Over time, as a country develops, the shape of its population pyramid changes from a triangular shape to a barrel-like shape with straighter edges.

• Later as countries become more developed they might have an aging population and a very low birth rate. When this happens the structure that looks a little like an upside-down pyramid.

Let’s practice drawing one together.

Age Male Female0-19 15 14

20-39 16 16

40-59 12 12

60 & Over 7 9

Compare Schofield Barracks, Hawaii to Bella Vista, Arkansas. What are some potential reasons that might cause the ages to be distributed in this way?

What are some areas of demographic focus of population pyramids?

1. Birth Rate2. Death Rate3. Infant mortality4. Life expectancy5. % of dependants to economically

active6. Migration

Homework• Mr. Jihad just received a population pyramid, but he does

not know how to read it. In a letter, explain to Mr. Jihad what a population pyramid is and how to interpret a population pyramid. • Choose a population pyramid.

• Explain first why population pyramids are important. i.e. what purpose do they serve.

• Explain the basic components of a pyramid and the difference in shapes of the pyramids.

• Explain the trends that one can notice from a population pyramid using your selection as your specific example.