Question

Explain the diagram of a population pyramid. Also show the three types of pyramids.

Answer 1

The diagram of a population pyramid consists of bars arranged in the form of a pyramid. The bars show different age groups, with the males on the left and females on the right. The base represents the youngest age group and the top represents the oldest. The shape of the population pyramid shows the characteristics of the population.

The three types of pyramid are :

1. Expanding population : In this case, the age-sex pyramid is more or less triangular with a broad base and a narrow top. The broad base shows large population of young people which indicates high birth rate. The narrow top shows high death rate in the older age group. Such a pyramid indicates rapid population growth. For example, countries like Bangladesh, India, Mexico, Nigeria have such a population pyramid.
2. Constant Population : The shape of the pyramid is like a bell, with the narrow top and a broad middle for several bars. This shows that the birth rate is almost equal to the death rate, leading to a constant population with the percentage of males and females remaining almost the same. Usually, developed countries such as the USA have this kind of a pyramid.
3. Declining Population : Such a pyramid has a narrow base, a bulging middle that indicates low birth rate and death rates and a slightly narrow apex. Countries like Japan, Germany and Italy have this kind of a pyramid.