1. Population Pyramids and Demographic Transition Model
Population changes over time and space.
2. Population change can be shown on two models.

2. The population pyramid displays the age
POPULATION STRUCTURE
The population pyramid displays the age
and sex structure of a country or given area
OLD DEPENDANTS
ECONOMICALLY
ACTIVE
YOUNG
DEPENDANTS
Population in
Five Year
Age bands
FEMALES
To the right
MALES
To the left
Usually, but not always,
in % to make for easier
comparisons
between countries

3. What Population Pyramids Show Us
KEY
The overall shape of the population pyramid can indicate whether it is an
Economically More Developed Country or Economically Less Developed Country
Economically
More
Developed
Country
Less
slope of pyramid indicate the death rate
height of graph can indicate life expectancy (ignore the very thin end of the wedge as occurs on graph B as these people are a definite minority)
proportions of men and women can suggest male or female migrations
"kinks" indicate dramatic reductions in birth rate or increases in death rate in the past
width of the base is related to birth rate/fertility rate
area of graph indicates total population - compare areas of different population age groups or different sex on one graph

4. The DTM (Demographic Transition Model)
The three key components to pay attention to in the Demographic Transition Model are:
Birth Rates
Death Rates
Total Population
The vertical on the graph is rate per 1000 and the horizontal is time.

5. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage A
Both high birth rates and death rates fluctuate in the first stage of the population model giving a small population growth (shown by the small total population graph).

6. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage B
Birth rates remain high, but death rates fall rapidly causing a high population growth (as shown by the total population graph).

7. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage C
Birth rates now fall rapidly while death rates continue to fall. The total population begins to peak and the population increase slows to a constant.

8. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage D
Both birth rates and death rates remain low, fluctuating with 'baby booms' and epidemics of illnesses and disease. This results in a steady population.

9. (Demographic Transition Model)
The DTM
(Demographic Transition Model)
Stage E?
A stage 5 was not originally thought of as part of the DTM, but some northern countries are now reaching the stage where total population is declining where birth rates have dropped below death rates.

10. Combining Both Models

11. Population Pyramids related to the Demographic Transition Model
Stage 1
Stage 2
Stage 3
Stage 4
IMPLICATIONS
Both birth rates and
Death rates are
High, so population
growth rates are
slow but population
Is usually restored
Due to high birth
Rate. Short life
Expectancy
EXAMPLES: Afghanistan, Ivory Coast
Population starts
to grow at an
exponential rate due to fall in Crude Death Rate. More living In middle age.
Life expectancy rises
Infant mortality rate falls.
EXAMPLES: Jordan, Thailand
Population continues
to grow but at slower
rate. Low C Death Rate.
Dramatically declining
Crude Birth Rate.
EXAMPLES: Ireland, China, New Zealand
Low Crude Birth Rate
and Crude Death Rate
Higher dependency ratio
and longer life expectancy
Crude Death Rate does
Rise slightly because of
The ageing population
EXAMPLES: United States, Japan
There is some merit in including or considering
a Stage 5 today with a declining population