Population Pyramids (Cambridge International IGCSE Environmental Management)

Population structure

• Population structure describes the composition of a population by age and sex
• It shows how many males and females are in different age groups
• Population structure affects the demand for services such as schools, hospitals and pensions
• Governments use population structure data to plan for the future

Age groups within a population

• Young dependants are people aged 0–14 who rely on adults for food, housing and education
• Working population includes people aged 15–64 who are economically active and support the economy
• Elderly dependants are people aged 65 and over who may require healthcare and pensions
• The ratio of the female and male population
• One of the main tools used to show population structure is a population pyramid

Interpreting population pyramids

What is a population pyramid

• A population pyramid (also known as an age structure graph) is used to display the gender and age structure of a given population
• Age groups are shown on the vertical axis, usually in five-year bands
• Males are shown on the left and females on the right
• The width of each bar represents the size of the population in that age group
• As countries develop, the shape of the population pyramid changes

Interpreting a typical population pyramid

Types of population pyramid

Expansive population pyramids

• Expansive pyramids have a wide base and a narrow top

• They show high birth rates and a large young population

• Death rates may be high and life expectancy is often lower

• Common in many low-income or developing countries

• These countries may face pressure on schools, healthcare and employment in the future

  • Examples include Nepal and Niger

Expansive population pyramid

Expansive population pyramid

Stationary population pyramids

• Stationary pyramids have a more even, rectangular or bell shape

• Birth rates and death rates are both low

• The population grows slowly or remains stable

• Common in more developed countries with good healthcare and education

  • Examples include Italy and the USA

Stationary population pyramid

Stationary population pyramid

Constrictive population pyramids

• Constrictive pyramids have a narrow base and wider middle or upper sections

• They show low birth rates and an ageing population

• Life expectancy is high

• These countries may face labour shortages and increased pressure on healthcare and pensions

  • A good example is Japan with its ageing population

Constrictive population pyramid

Migration population pyramids

• 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

Why population pyramids are useful

• They help identify future population growth or decline
• They show the size of the future workforce
• They highlight dependency ratios
• They help governments plan for education, housing and healthcare

Worked Example Define population structure.

[2 marks]

Answer

Population structure refers to the age and sex composition of a population [1] **and shows how many males and females are in different age groups. [1]

Mark allocation

• 1 mark**[1] **for reference to age and sex.
• 1 mark**[1] for explanation of population composition.

Examiner tips

Do not confuse population structure with population distribution.