Use a population pyramid to explain changes in a country's population structure.

The world's population is growing exponentially, yet populations of some countries are not experiencing the same trend. In general, LEDCs see continued increases in their populations and MEDCs have reached the peaks of their populations and now have falling populations. Using the demographic transition model we are able to see how population pyramids change shape according to the specific stage reached by a country. These stages reflect the changing crude birth and death rates of a country according to the level of development it has reached. Dependency ratios can also be illustrated by population pyramids. Dependency ratios are calculated by dividing the number of dependents (children under 16, retired population) by the working population x100, presented as a percentage. A high dependency ratio is displayed in a bell-shaped population pyramid - highly youthful population with more dependents than the working population. Case Study: Japan Looking at Japan's population pyramid we can see that the country is in stage 5 of the demographic transition model. Japan has a high life expectancy and a low birth rate. We can see that they have a high life expectancy due to the higher proportion of the population in the 65+ age group. On the other hand, the low birth rate is shown as a result of the falling size of the population groups below 35 yrs. This is evidence that less babies are being born every generation. Case Study: Bahrain (anomaly) By contrast Bahrain presents a population pyramid unlike many others. Notably there is a large number of men between the ages of 20-45 yrs old. This can be explained by the level of migration of male workers into the country - whether this be in the form of expats or manual workers.