Population Pyramids
- The characteristics of a population, the distribution of age, sex, ethnicity, religion etc, is known as the population structure
- It is the result of changes in:
- fertility
- mortality
- migration
- The two main components of age and sex can be shown on a population pyramid
Population pyramids
- Population pyramids (also known as an age structure graph) are used to display the gender and age structure of a given population
- They illustrate the distribution of the population across age groups and between male/female
- They enable governments nationally and regionally to assess the needs of the population for services such as healthcare and education
- This means the governments can estimate and plan for spending
- As countries develop and pass through the stages of demographic transition the shape of the population pyramid changes
- The population pyramid can be used to identify the following groups:
- Young dependents
- Old dependents
- Economically active (working population)
- Dependency ratio
Population Pyramid - Niger
- LEDCs like Niger have a concave pyramid shape
- At the start of stage 2 of the demographic transition model
- This indicates:
- High birth rate
- Low life expectancy
- High death rate but starting to decrease
- High infant mortality rate
- Young dependent population dominates
Population Pyramid - Nepal
- LEDCs/NICs that are a little further along the demographic transition such as Nepal has a convex pyramid shape
- Stage 3 of the demographic transition model
- This indicates:
- Decreasing birth rate
- Increasing life expectancy
- Decreasing death rate
- Decreasing infant mortality
- Larger working age population
Population Pyramid - USA
- HIC countries such as the USA have a column shape
- Stage 4 of the demographic transition model
- This indicates:
- Decreasing birth rate
- Increasing life expectancy
- Decreasing death rate
- Low infant mortality
- Larger working age population
Population Pyramid - Japan
- HIC countries such as Japan have a pentagon shape with a narrowing base
- Stage 5 of the demographic transition model
- This indicates:
- Decreasing birth rate
- Increasing life expectancy
- Death rate is higher than the birth rate due to the ageing population
- Low infant mortality
- Ageing population - older dependent population
Implications of population structure
- Population pyramids mean that population issues can be identified
- There are a range of issues including:
- Ageing populations
- Falling birth rates
- Impacts of migration
Ageing populations
- Many HICs are experiencing ageing populations and an increase in the older dependent population, the implications of this include increased:
- Pension payments
- Need for care homes
- Pressure on the healthcare service and social care
- It also results in fewer workers which means:
- Governments are not able to collect as much tax
- Some areas suffer worker shortages
Falling birth rates
- Countries experiencing falling birth rates include many HICs and MICs, the implications of this include:
- School closures due to fewer children
- Future workforce shortages
Migration
- In some countries, migration can lead to an imbalance in the population structure
- The UAE has significantly more males than females
- 29% of the population are males between the ages of 25 and 39 whereas only 10.5% of the population are women 25-39
- This is the result of the migration of males to the UAE to work in the oil, gas and construction industries
- Rapid population growth in some areas as a result of migration can lead to:
- Increased pressure on services such as healthcare and schools
- A shortage of housing
- Increased traffic congestion
- Increased water and air pollution
- Shortage of food
- Lack of clean water
Exam Tip
When interpreting a population pyramid you need to look at four key areas
- Young dependents - is the birth rate high or low?
- Working population - are there enough people of working age to support the young and old dependents?
- Old dependents - is it large or small? If it is large, then life expectancy is high
- Male/female split - are there any noticeable differences between the numbers of males and females?
To calculate the dependency ratio: