1. The Demographic Transition Model (DTM)

2. We are learning to…
Describe how the population changes at each stage of the DTM
Explain why birth and death rates change at each stage
Give example of countries that fit into each stage

3. I Can… Interpret each stage of the DTM
Give an account of the reasons behind the changes in birth and death rates at each stage
Give examples of countries that fit each stage

4. Population Changes
The total population of an area depends upon changes in the natural increase and migration.
The natural increase (or decrease) is the difference between the birth rate and the death rate.
The birth rate is the number of live births in a year for every 1000 people in the total population.
The death rate is the number of people in every 1000 who die in a year.
If the birth rate is higher then the total population will increase. If the death rate is higher then the total population will decrease.

5. The Demographic Transition Model
The DTM describes a sequence of changes in the relationship between birth rates and death rates.
The model was produced using changes in the natural increase in several industrialised countries in western Europe and North America.
It suggests that the population growth rates for all countries can be divided into five stages

6. The Model

7. Stage 1 – A high stationary population
Both birth rates and death rates are very high
Total population is very low
Natural increase is low
There are very few countries in stage 1 today – possibly only remote groups in the rainforest
The UK was in Stage 1 before 1760

8. Stage 2 – An early expanding population
Birth rates are still high
Death rates are falling
Total population is increasing
Natural increase is high
Some of the poorest developing countries are still in Sage 2 e.g. Malawi and Bangladesh
The UK was in Stage 2 between 1760 and 1900

9. Stage 3 – A late expanding population
Birth rates are falling
Death rates are also continuing to fall
Total population is increasing
Natural increase is quite high
Most developing countries are in Stage 3, such as Brazil.
The UK was in Stage 3 between 1900 and 1950

10. Stage 4 – A low stationary population
Birth rates and death rates are low
Total population is steady
Natural increase is very low
Most developed countries are in Stage 4, such as the UK and USA.
The UK has been in Stage 4 since the 1950s

11. Stage 5 – A declining population
Death rates remain low
Birth rates are low and decreasing
Total population is decreasing
Natural increase is negative
Some developed countries are now in Stage 5, such as Australia and Germany

12. Population structures
The rates of natural increase, births, deaths, infant mortality and life expectancy all affect the population structure of a country.
The population structure of a country can be shown by a population or age-sex pyramid.

13. Population pyramids show
The total population divided into five-year age groups
the percentage of people in each of those age groups
the percentage of males and females in each age group

14. The age and sex structure of a country or area
Population Pyramid USA 2010
Population in 5 year age bands
Old Dependants
Economically Active
Young Dependants
Usually, but not always in % to make for easier comparisons between countries
Females to the right
Males to the left

15. What Population Pyramids Show Us
KEY
Economically
More
Developed
Country
Economically
Less
Developed
Country
slope of pyramid indicate the death rate
width of the base is related to birth rate/fertility rate
proportions of men and women can suggest male or female migrations
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)
"kinks" indicate dramatic reductions in birth rate or increases in death rate in the past
area of graph indicates total population - compare areas of different population age groups or different sex on one graph
The overall shape of the population pyramid can indicate whether it is an
Economically More Developed Country or Economically Less Developed Country

16. Population pyramids are useful because they 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).
Dependency ratio = (% children 0-14) + (%the ‘aged’ 65+)
% economically active adults 15-64
X 100

17. Population pyramids in relation to the DTM

18. Task
% population aged 0-14
% population aged 15-64
% population aged 65+
Dependency ration
Comment
Country A 15 66 19
Country B 44 51 5
Study the table above. Copy and complete the figures for dependency rations, then comment on your findings

19. Task Copy the following:
The seven key points when describing and explaining a population pyramid
Note the country and the date
Note the horizontal axis: males usually to the left and females to the right
Note the horizontal scale: % or raw numbers in millions
Note the age cohorts (usually in five-year bands)
Note the general shape
Identify % in age cohorts. Suggestion - the young aged 0-14, the aged (usually 65+), the percentage of 85+. Then calculate the dependency ratio
Look for gender differences, e.g. with the elderly, are there more women than men? Also are there more baby boys than girls?

20. Task
Using the seven-point scale, complete your analysis of the population pyramids for China and Senegal