Population pyramids and the demographic transition

A population pyramid is a graph showing a population's age and sex structure, with the youngest age groups at the bottom. A pyramid with a wide base, like Niger's, shows a young population with high birth rates and fast growth; a straighter, column-like shape shows slow growth; and a pyramid narrower at the bottom than in the middle, like Japan's, shows an aging population that may shrink. The demographic transition model describes how populations have changed as countries developed: in Stage 1, birth and death rates are both high and growth is slow; in Stage 2, death rates fall thanks to better food, sanitation, and medicine while birth rates stay high, so the population grows rapidly; in Stage 3, birth rates fall as people move to cities, education spreads, and women gain more choices, so growth slows; in Stage 4, both rates are low and growth levels off; and some geographers add a Stage 5 in which births fall below deaths and the population declines. The natural increase rate is the birth rate minus the death rate. The model is based mainly on Europe's history, so not every country follows it exactly. Thomas Malthus argued in 1798 that population would outgrow the food supply, but advances in farming technology have so far outpaced his prediction, though neo-Malthusians still warn about resource limits.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report