World Population: Distribution, Density, Growth, Composition and Human Development
Domain 2: World Population - Distribution, Density, Growth, Composition and Human Development
The exam tests your ability to interpret uneven distribution, calculate density, explain growth and composition, and link population data to human development.
Core rules
- Distribution is uneven. Most people live between about 20°N and 60°N, especially in monsoon Asia, Europe and eastern North America; drylands, high mountains and polar regions are sparsely peopled.
- Arithmetic density = total population divided by land area. Physiological density = population divided by cultivable land. Agricultural density = farm population divided by cultivable land.
- Natural increase = births minus deaths. Total growth also includes net migration. Doubling time is approximately 70 divided by annual growth rate in per cent.
- The demographic transition moves from high stationary, through early and late expanding, to low stationary stages; each stage produces a different age-sex pyramid.
- Composition includes age, sex, dependency ratio and workforce. Dependency ratio = population aged 0–14 plus 65 and above, divided by population aged 15–64, multiplied by 100.
- HDI combines life expectancy, education and GNI per capita; it is not merely income.
Worked example
Country A has 50 million people and 250,000 km². Arithmetic density is 200 per km². If only 100,000 km² is cultivable, physiological density is 500 per km². If 20 million are under 15, 5 million are over 64 and 25 million are 15–64, the dependency ratio is 25/25 × 100 = 100. A high HDI still requires strong education and health, so a rich country with poor schooling can rank lower.
Traps
Do not treat density as crowding; sparse land can still have crowded cities. Do not confuse growth rate with natural increase. Do not reduce HDI to GDP, and do not read a pyramid without separating age groups.