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Population pyramids and demographic transition models - Coggle Diagram
Population pyramids and demographic transition models
Population Pyramids
A special bar graph that shows the age and gender structure of a country’s population.
One side shows males, the other side shows females.
Vertical axis → Age groups (usually 5–10 years).
Horizontal axis → Number or percentage of people in that age group.
Overall composition and structure of a population.
Number of young, middle-aged, and older people.
Whether there are many young people or few old people.
Whether there are more older women than men.
If the population is expanding or shrinking.
Signs of mass immigration or emigration.
If there are male/female migrant workers in certain age groups.
Impacts of wars or natural disasters on the population.
Uses of Population Pyramid Information
Helps government planners and businesses decide:
Do more schools need to be built?
Are more care facilities for elderly people needed?
Is the market for goods expanding or shrinking?
Should the government encourage or discourage births?
What the Shape of Population Pyramids Shows
Indicates level of economic development:
Developing countries → triangular/pyramid shape.
Developed countries → narrow, oblong shape.
Broad base → youthful population, high birth rate.
Narrow base with bulge in the middle → lower birth rate, aging population, good birth control.
Shape changes over time as countries develop.
Shows workforce structure:
Ages 15–64 = economically active population.
Ages 0–14 and 65+ = dependents.
Slow Growth, Gradually Expanding Population (e.g., USA)
Pyramid shape: Bell-shaped, wider in the middle.
Birth rate (BR): Decreasing, but still slightly higher than death rate (DR).
Death rate (DR): Decreasing.
Natural increase (NI): Low, but still positive.
Age structure: More middle-aged people.
Life expectancy (LE): Longer, with females generally living longer than males.
Stable, Static Population (e.g., Poland)
Pyramid shape: Bell-shaped, nearly vertical sides.
BR & DR: Both declining and almost equal.
Natural increase (NI): Around 0% (zero population growth).
Age structure: Almost constant numbers up to age 60.
LE: Longer, females live longer than males.
Population size remains stable, not growing or shrinking.
Declining, Diminishing Population (e.g., Austria, Germany, Japan)
Pyramid shape: Can be asymmetrical, narrow base.
BR & DR: Both low, but DR may exceed BR.
Natural increase (NI): Negative (shrinking population).
Age structure: More middle-aged and older people than young people.
LE: Longer, especially for females.
Population shrinks over time due to low births and aging.
What is the Demographic Transition Model (DTM)?
A geographical model showing how birth rates (BR), death rates (DR), and population growth change over time.
Based on historical data from countries such as USA, Britain, Japan, Sweden.
Represents a general trend, not the exact situation of a single country.
Also called the population cycle model.
Helps compare demographics of different countries and predict future trends.
Most countries are expected to move through all 4 stages eventually.
Stage 1 – High Stationary Phase
BR: High (no birth control, children valued as workers/status symbols).
DR: High (due to disease, famine, war, poor hygiene, poor diet, lack of medical care).
Total population: Low and stable (little growth).
Fluctuations caused by famine, plagues, or wars.
IMR (Infant Mortality Rate): High.
Demographic Transition Model (DTM)
Explains the relationship between BR, DR, and population growth over time.
Shows how populations change as countries develop.
Most countries are expected to pass through all 4 stages, but some may enter a 5th stage.
Stage 1 – High Stationary Phase
BR: High (no birth control, children needed for work/status).
DR: High (famine, disease, poor hygiene, poor medical care).
Population growth: Low and fluctuating.
LE: Short, IMR: High.
Stage 2 – Early Expanding Phase
BR: Remains high.
DR: Drops rapidly (better medical care, improved diet, sanitation, fewer wars).
Population growth: Rapid increase → “population explosion.”
LE: Increases, IMR: Decreases.
Stage 3 – Late Expanding Phase
BR: Drops significantly (urbanisation, industrialisation, access to contraception, higher education for women).
DR: Low and stable.
Population growth: Slows down.
Population size: Still increases, but at a slower rate.
Stage 4 – Low Stationary Phase
BR and DR: Both low and stable.
Population growth: Very little or none (zero population growth possible).
Population size: Stable, high life expectancy.
If BR drops below DR → negative natural increase (population decline).
Stage 5 – Declining Populations (suggested extension)
Seen in highly developed countries (e.g., Germany, Japan).
BR: Falls below DR.
Population growth: Negative (shrinking population).
Population structure: Aging population, more elderly dependents.