Population pyramid
Also called: Age-sex pyramid · Topic: Graphical Representation of Data and Thematic Maps · NCERT: Beyond NCERT
Meaning
A population pyramid, or age-sex pyramid, is a pair of horizontal bar graphs placed back to back. Males are on one side and females on the other. Each bar shows the share of people in one age group, with the youngest at the bottom. The shape tells the story. A wide base means many children, which means high fertility (a high birth rate). A narrow base with a wider top means fewer births and more old people, which is an ageing population.
Example
Bihar's pyramid has a wide base, showing high fertility. Kerala's has a narrower base and a wider top, showing an ageing population, as does Japan's.
Don't confuse with
- Multiple bar diagram: this places bars side by side to compare variables. A pyramid places male and female bars back to back along age groups to show a population's structure.