Reasons for & Implications of Different Population Structures (Cambridge (CIE) IGCSE Geography)

Population Pyramids

• The characteristics of a population—the distribution of age, sex, ethnicity, religion, etc.—are known as the population structure

• The population structure 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 and 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 

• LEDCs like Niger have a concave pyramid shape

• Stages 1 and 2 of the model and this indicates:

  • high birth rate

  • low life expectancy

  • high death rate but starting to decrease

  • high infant mortality rate

  • a young dependent population dominates

• LEDCs/NICs that are a little further along the demographic transition, such as Nepal, have 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

• MEDC 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

• MEDC 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

  • The 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 MEDCs and NICs; the implications of this are:

  • 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 

• Approximately 29% of the population are males between the ages of 25 and 39, whereas only 10.5% of the population are women between 25 and 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

  • a shortage of food

  • a lack of clean water

Case Study: Japan