The Stages of the DTM

B - Stage 2

Birth rates remain high, but death rates fall rapidly causing a high population growth (as shown by the total population graph). The reasons for this could be:

* improvements in medical care - hosppitals, medicines, etc.

* improvements in sanitation and water supply

* quality and quantity of food produced rises

* transport and communications improve the movements of food and medical supplies

* decrease in infant mortality.

C - Stage 3

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. The reasons for this could be:

* increased access to contraception

* lower infant mortality rate means there is less need to have a bigger family

* industrialisation and mechanisation means fewer labourers are required

* the desire for material possessions takes over the desire for large families as wealth increases

* equality for women means that they are able to follow a career path rather than feeling obligated to have a family.

D - Stage 4

Both birth rates and death rates remain low, fluctuating with 'baby booms' and epidemics of illnesses and disease. This results in a steady population.

E? - Stage 5?

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. One such country is Germany, which has taken in foreign workers to fill jobs. The UK's population is expected to start declining by 2021.

Examples

Population changes over time and space and the DTM can show both of these. Examples for both of these are shown below. Firstly, examples of countries that can be classed as exhibiting the population traits now, are shown as an example of how population can change over SPACE. Secondly, the dates the UK passed through each stage are indicated as an example of how population in one country can change over TIME.

A1

Stage 1

Ethiopia / Bangladesh

UK: pre-1780

B1

Stage 2

Sri Lanka / Brazil

UK: 1780 - 1880

C1

Stage 3

Uruguay / China

UK: 1880 - 1940

D1

Stage 4

Canada / Japan

UK: post-1940

Comparing with the PPM

Each of the stages of the Demographic Transition Model (DTM) can be directly compared to the stages of the Population Pyramid Model. The chart below indicates ways in which the DTM and PPM differ or are similar in their structure.

Demographic Transition Model

Population Pyramid Model

* drawn as a line graph

* doesn't show male and female populations

* shows total population as a separate line

* gives details of countries in stages

* shows the relationship between birth and death rates and how these affect total population obviously (using the line graphs)

* only one diagram necessary to show all stages

* drawn as a bar graph

* shows male and female population proportions

* total population is shown as the total area of the graph

* shows greater detail about the populations at each stage (amount in each age and gender at any one time)

* shows direct relationship between birth and death rates and how these affect total population indirectly (through the shape of the diagrams)

* four diagrams necessary to show all stages