 A population pyramid is a pyramid shaped diagram showing the age and sex distribution of a population. Figure 1: A population pyramid.

 The pyramids of these countries usually indicates a high birth rate hence the base of the pyramid is wider that the top.  The top of these pyramids are narrower indicating that there are fewer people in the older age group because life expectancy is lower.  Such countries have a youthful population with a rapid growth rate.

 The pyramids of these countries have a narrow base which means the birth rate is low.  The tops of the pyramids in these countries are wider indicating a longer life expectancy.  Such countries are said to have a slow population growth.  They are also faced with the issue of having an ageing population.

 A wide base suggest a high birth rate, a youthful population and a rapidly growing population.  A narrow base tells us that birthrate is low.  Straight or near vertical sides tells us that the death rate is low.

 Sides that narrow inwards from the bottom shows a high death rate.  Large number of people around the age groups indicates a high rate of immigration.  A small number of young people indicates high rates of emigration.