StudyDeck

1.3.1 Reasons for & Implications of Different Population Structures

Exam code: 2217
Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Population Pyramids

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

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

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

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

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

Case Study: Japan

Case Study: Japan

  • Japan's population is decreasing, falling from 128 million in 2007 to 125.8 million in 2020

  • The fertility rate is 1.36 births per woman which is well below the 2.1 fertility replacement rate

  • The birth rate is 6.8 per 1000

  • The death rate is 11.1 per 1000 

    • The death rate has increased from 6 per 1000 in 1979

    • This is not because healthcare or diets are worse but because there are far more elderly people who are more likely to become ill and die

  • Japan has the highest life expectancy in the world at 84.36 years

population-pyramid---japan
  • Increasing life expectancy in Japan has led to an ageing population with an increasing proportion of elderly dependents

  • The issues that this has led to include:

    • Increased pressure on health and social care

    • Greater cost in providing pensions

    • More use of public transport as the elderly age group is less likely to drive

    • Increased need for care homes 

    • Shortages of workers as more people retire and there are not enough economically active people to take their place

  • These issues are further increased by the falling birth rate 

  • The future impact on Japan may include:

    • Increased taxes to cover health, social care and pension costs

    • Continued population decrease

    • Reduced economic development due to a shortage of workers

    • Reconsideration of the immigration policies which are currently very strict

    • Introduction of pro-natalist policies to increase the birth rate and encourage larger families