Population Pyramids and Demographic Transition Model

DTM is based on experiences of the UK and some other industrialised countries during 19th century and 20th century. It looks at development - in terms of death rates, birth rates and total population. It goes through four stages, but it could be argued that there are five.

A period of high birth rates and high death rates that fluctuate. Population growth is small.

Reasons for high birth rate:

• limited birth control/family planning
• high infant mortality
• children are a future source of income
• culture believes children are a sign of fertility
• religions encorage large families

Reasons for high death rate:

• high incidence of disease
• poor nutrition and famine
• poor levels of hygiene
• underdeveloped and inadequate health facilities

A period of high birth rate, but falling death rates. Population begins to expand rapidly.

Reasons for falling death rate:

• improved public health
• better nutrition
• lower child mortality
• improved medical provisions

A period of falling birth rates and falling death rates. population growth starts to slow down.

Reasons for falling birth rate:

• changing socioeconomic conditions
• greater access to education for women
• preferences for smaller families
• rise in materialism
• increased personal wealth
• compulsory schooling, making rearing children more expensive
• lower infant mortality rate
• avaliablity of family planning systems

A period of low birth rate and low death rate, both of which fluctuate. Population growth is small and fertility continues to fall. There are significant changes in personal lifestyles, more women in the work force, with many people having high incomes and more leisure interests.

A later period when death rate exceeds birth rate. This causes population decline. This stage has only recently been recognised in some Western European countries

Reasons for low birth rate:

•  Rise in individualism, linked with emancipation of women
• Greater financial independence of women
• Concern about the impact of increased population numbers on resources
• Increase in non traditional lifestyles such as same sex relationships
• Rise in the concept of childlessness
• Death rate may slightly increase due to aging population

Strengths:

• dynamic, showing change through time
• discribes what happened in the UK
• other countries in Europe and North America went through similar stages
• Newly Industrialised Countries (NIC's) go through same stages just faster
• Explains what happens and why

Weaknesses:

• not relevant to non industrialising countries
• model assumed stage 2 followed industrialisation. Death rates falling due to medical care, sanitation from colonised countries
• model assumed stage 3 followed several decades after stage 2 and that death rate fell due to changes in birth rate. Attitudes towards contraception barred this and government interventions provide an anomaly, such as chinas one child policy
• original model adapted to add stage 5 which can be seen in East and Central Europe
• Countries affected by HIV/AIDs appear to have slipped back into stage one.
• doesnt predict countries future

• 1700-1760 birth and death rates are high and fluctuating (STAGE ONE)
• 1760-1880 death rates are falling and birth rates remain high (STAGE TWO)
• 1880-1940 death rates continue fall and birth rates decline (STAGE THREE)
• 1940-1980 birth and death rates are low (STAGE FOUR)

Anomalies:

• Birth rate rises between 1700-1840 (would be expected to be constant) due to better records of birth and deaths
• Death rates rise between 1820-1840 due to increase contagion from people living in greater proximity
• Death rates rise around 1916-1940 due to World Wars
• Rise in birth rate in the 50's and 60's due to post war baby boom

• Birth and death rates start off high in 1891 and fluctuate until 1921 (STAGE ONE) 
•   From 1921-1981 death rates rapidly decline, but birth rates remain high (STAGE TWO)
• 1981 both death rates and birth rates decline at a slow rate (STAGE THREE)

However birth rate dropped rapidly between 1921 and 1951, but rose again and then dropped again in 1981