O Level Geography: Population and Settlement — Revision Notes

Condensed for the final weeks. For the full explanation, use the Population and Settlement study guide.

Population change

natural increase  = birth rate - death rate
population change = natural increase + net migration

Rates are per 1,000 per year. Forgetting migration is the commonest calculation error.

The Demographic Transition Model

Stage	Birth rate	Death rate	Growth
1	High	High	Low
2	High	Falling fast	Very high
3	Falling	Low	Slowing
4	Low	Low	Low
5	Below death rate	Low	Negative

The population explosion happens in stage 2 because of a timing gap. Death rates fall quickly with better medicine, sanitation, clean water and food supply; birth rates stay high because attitudes, religion and the economic value of children change far more slowly. That lag is the model.

Birth rates fall in stage 3 because of contraception, female education and employment, lower infant mortality (so fewer births are needed), urbanisation, and the rising cost of raising children.

Limitations: based on European experience, ignores migration, assumes one universal path, gives no timescale.

Population structure

• Wide base, steep sides → high birth and death rates, stage 2. Youthful population.
• Straight sides, narrow base → stage 4 or 5. Ageing population.

Reading a pyramid beyond overall shape earns the higher marks. A sudden narrowing at a specific age band can point to a past event affecting that cohort — war, famine or emigration. A bulge can point to a past baby boom or in-migration of a particular age group. The strong technique is shape first, for the stage of development, then specific irregularities and their likely cause — not simply describing “more males than females in this age group.”

dependency ratio = (under 15 + over 64) / (15-64) x 100

Ageing population: rising pension and healthcare costs, shrinking workforce, higher taxes on workers. Responses: raise the retirement age, encourage immigration, pro-natalist policies.

Youthful population: pressure on schools and healthcare, future unemployment, food and housing pressure — but a large future workforce.

Population policies: anti-natalist (China’s former one-child policy) versus pro-natalist (France, Singapore). Both illustrate that policy can influence birth rates, but also that unintended consequences follow — China’s policy produced a distorted sex ratio and an ageing crisis.

Migration

Push: unemployment, poverty, conflict, disaster, persecution, poor services. Pull: jobs, higher wages, better services, safety, family already there.

	Benefits	Problems
Receiving country	Fills labour gaps, young taxpayers, cultural diversity	Pressure on housing and services, possible tension
Source country	Remittances, less unemployment, returnees bring skills	Brain drain, loss of working-age people, split families

Always evaluate both countries. That structure is what the mark scheme expects.

Settlement

Site is the land a settlement is built on; situation is its position relative to other places. Site factors: water supply, dry point, defence, relief, aspect, building materials, fertile land.

Settlement hierarchy: as settlements get larger, there are fewer of them, and their range and number of services increase.

• Range — how far people will travel for a service.
• Threshold population — the minimum number needed to support it.
• Sphere of influence — the area served.

A department store has a high threshold and large range, so there are few; a newsagent has a low threshold and small range, so there are many.

Settlement and service provision are causally linked, not two separate topics. A settlement’s size, function and connectivity — its site and situation — directly determine what services it can support, so a larger, more central settlement typically has a wider range and higher order of services than a small, isolated one. Exam questions frequently ask why a settlement has, or lacks, a particular service, which requires this cause-and-effect reasoning rather than a description of the hierarchy alone.

Urban land use: CBD (accessible, high land values, tall buildings), inner city (old industry, terraced housing), suburbs (lower density, newer), rural–urban fringe.

Urbanisation

Driven by rural–urban migration plus high natural increase among the young migrant population — a point often missed, since migrants are disproportionately of childbearing age.

Problems in LICs: informal settlements, inadequate water and sanitation, congestion, air pollution, unemployment and underemployment, crime.

Solutions: site-and-service schemes, self-help schemes with materials and training provided, improved public transport, and rural development to reduce the push factors — which addresses the cause rather than the symptom.

Exam traps

• Omitting migration from population change.
• Saying birth rates fall in stage 2 — they fall in stage 3.
• Describing the DTM rather than explaining the mechanism.
• Evaluating migration from one country’s viewpoint only.
• Confusing site with situation.
• Generic answers with no named examples, figures or dates. Case study detail is where the top band lives.

Self-test

1. Give the formula for population change in full.
2. Why does population grow fastest in stage 2?
3. Give the dependency ratio formula and what a high value means.
4. Give two benefits and two problems of emigration for the source country.
5. Distinguish range from threshold population.

Answers: 1. Natural increase (birth rate minus death rate) plus net migration. 2. Death rates fall rapidly with improved medicine, sanitation and food supply while birth rates remain high because social attitudes change far more slowly, so the gap between the two is at its widest. 3. (Under 15 + over 64) ÷ (15–64) × 100; a high value means a large dependent population supported by a small working population. 4. Benefits: remittances sent home and reduced unemployment. Problems: brain drain and families separated. 5. Range is how far people will travel to use a service; threshold population is the minimum number of people needed to make it viable.