Population Pyramids

Objective - Today, students will be able to
know what a population pyramid is and what
we can learn from their different shapes.
• On a sheet of notebook paper, please
answer the following.
– What is CBR? (definition, not just what the
acronym stands for.)
– What is CDR?
– What is TFR?
What is a population pyramid?
A visual representation of the population of a
• graphically display a population's age and
gender composition
• show numbers or proportions of males and
females in each age group
• show gains of members due to immigration and
birth, and loss of members due to emigration
and death
• reflect population growth or decline
Interpreting a
Population Pyramid
•Remember that a population pyramid
is basically a bar graph turned on its
side. Each line is showing you what
percentage of the population is a
certain age.
•Examine the title and the type of data
presented. (ex. Age breakup, numbers
listed below, male-female notation.)
How to interpret population
There main types of
– Rapid growth
– Slow growth
– Negative growth
Shape of rapid
Shape of
Slow growth
Shape of negative
Rapid growth
Rapid growth pyramids
• Have a large base to show high birth rates
• Amount of people decreases as the ages
goes up indicating a lower standard of
• Associated with developing countries like
Brazil, Uganda, China
Slow Growth
Slow growth pyramids
• Take on a more rectangular shape
• Indicates population is remaining fairly
• Birth rates and death rates are similar
• Associated with developed countries like
the UK, Germany, Canada
Negative growth
Negative growth pyramids
• Looks like a reverse pyramid
• Indicates the population of the country is
• Death rates are higher than birth rates
• Associated with developed countries like
Austria, Japan, Italy
Dependency Ratio
• The number of people under the age of 15
and over the age of 64 compared to the
number of people active in the labor force
• Q: What are some of the issues with
having a “too young” pop? Issues with a
“too old” pop?
Dependency Ratio Problems
Too Young: LDC/Stage 1/2
• Nearly ½ of the pop in
LDCs are dependents
• Provide: schools,
hospital, daycares-> if
girls don’t go to school
the TFR/CBR remain high
Too Old: MDC/Stage 3/4
• 1/3 pop in MDCs are
• $$ after retirement,
• 25% of budget in the US
and other MDCs goes to
programs for the elderly
Soviet Union
Enemies of the State
WWI- 1914-1918
1,700,000 military dead
December 1934
Stalin began a period of
purging and terror that
lasted until 1939 and was
marked by the execution
of virtually the entire
political and military elite.
• April 17th, 1975 the
Khmer Rouge, a
communist guerrilla group
led by Pol Pot, took
power in Phnom Penh,
the capital of Cambodia.
During their rule, it is
estimated that 2 million
Cambodians died by
starvation, torture or
During World War II
6 million Poles (about
one sixth of the
population) died,
including nearly 3
million Polish Jews
murdered in Nazi
death camps