What is an age pyramid?

Another attribute characteristic of a population is sex ratio. An individual is either a male or a female but a population has a sex ratio (e.g., 60 percent of the population are females and 40 per cent males). A population at any given time is composed of individuals of different ages. If the age distribution (percent individuals of a given age or age group) is plotted for the population, the resulting structure is called an age pyramid (Figure 11.1). For the human population, the age pyramids generally show the age distribution of males and females in a diagram. The shape of the pyramids reflects the growth status of the population - (a) whether it is growing, (b) stable or (c) declining.