Population pyramids

5.2.2 Demographic transition

5.3.1 Problems

Population pyramids

  1. A population pyramid is a type of bar graph used to show the age & gender structure of a country, city or other area
  2. The horizontal axis split into male & female, on the left & right side respectively, and shows the number or proportion of the population
  3. The vertical axis shows age categories, usually in 5-year cohorts

  4. Demographic transition model

    Population pyramid diagrams

    1. Each stage of the demographic transition model has a characteristic population pyramid associated with it
    2. Stage 1 pyramids have a very wide base due to their high birth rate, but a concave shape due to their high death rate, especially infant & child mortality, and a very low apex due to a low life expectancy
    3. Stage 2 pyramids have a slightly narrower base due to a decreasing birth rate, straighter sides due to a falling death rates and a higher apex due to a rising life expectancy
    4. Stage 3 pyramids have convex sides and a rapidly narrowing base due to falling birth rates
    5. Stage 4 pyramids have convex sides due to steadily low birth & death rates, with a higher proportion of elderly people due to a high life expectancy
    6. Stage 5 pyramids have a significantly higher proportion of elderly people and a low proportion of children