Factors influencing population structures (Cambridge International IGCSE Geography)

Specification link

This page covers section 6.2.1 of the CIE IGCSE specification .

• 6.2.1- Factors influencing population structures: natural increase and net migration.

Population pyramids

Spec point — "Candidates should be able to: • select, present, construct and communicate data through appropriate graphs, charts and diagrams using relevant scales and annotations to present information • extract, interpret, analyse and evaluate information presented on graphs, charts and diagrams • identify and evaluate variations, trends and patterns from data provided."

Population pyramids

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

• Information about these characteristics is gathered in a census

• 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

What is a population pyramid?

• 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

  • Each bar of the population pyramid represents a 5-year age range
  • The two sides of the population pyramid represent males (usually on the left) and females (usually on the right)

• The population pyramid can be used to identify the following groups:

  • Young dependants
  • Old dependants
  • Economically active(working population)
  • Dependency ratio

Interpreting a population pyramid

Demographic transition and population structure

• As countries move through the stages of demographic transition
• The shape of the population pyramids reflect the changes

Population pyramid of Niger 2010

• LEDCs like Niger have a concave pyramid shape

• Stages 1 and 2 of the model indicate:

  • high birth rate
  • low life expectancy
  • high death rate but starting to decrease
  • high infant mortality rate
  • a young dependent population dominates

Population pyramid of Nepal

• 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

Population pyramid of the USA

• 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

Population pyramid of Japan

• 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

Natural increase

Spec point — Factors influencing population structures: natural increase and net migration.

• Natural increase is calculated by subtracting the death rate from the birth rate

• The combination of a decreasing death rate and high birth rate led to rapid natural increase and population explosion

• The impacts on population structure often leads to

  • a larger overall population
  • a population with a larger proportion of younger people
  • a higher dependency ratio

Population structure of Niger

• A negative rate of natural increase happens when the birth rate is lower than the death rate

• When this occurs, it impacts the population structure, leading to:

  • a shrinking population
  • an ageing population

Population structure of Italy

Net migration

Spec point — Factors influencing population structures: natural increase and net migration.

• Net migration is calculated by subtracting the number of emigrants from the number of immigrants

  • The measurement is given per 1000 people

• Positive net migration occurs when there are more immigrants into a country than there are emigrants from the country

• Negative net migration occurs when there are more emigrants from a country than there are immigrants into the country

• 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

Population structure showing the impact of male dominated migration

• 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