Population Pyramids

What Are They? The composition of the population of a country can tell you a great deal about its development. The best way to look at this is by studying a population pyramid. This is basically back to back bar graphs, one showing the number of males, the other showing the number of females. The bars represent age bands of 5 year intervals.

Stages

What Do They Show? Different shaped population pyramids indicate the stage of development that a certain country has reached. Population pyramids can indicate the BR and DR of a country. For instance a country whose pyramid has a wide base has a high BR. If the numbers rapidly decrease, to form a triangular shaped pyramid, then there must also be a fairly high DR, and so the country is in either the first or second stage of development. A country in Stage four will have a relatively narrow base, and there will be similar numbers of people in all the bands up until 70, when the numbers will start to fall. This country would be one like the UK with good health care, and a high life expectancy.

What Do They Show? Population pyramids can also show the percentage of the population, which is described as being "dependant". These are the groups of people who rely on the economically active members of society. Dependants are classified as those under working age ( years old) and those who have retired (over 65). They rely on the working age group of people between 16 and 64.

What Do They Show? Population pyramids can also show significant events. In Germany there are far more males between 20 and 35, than there are females of a similar age. This shows up quite clearly on a pyramid, and is due to the huge numbers of male immigrant workers that came into the country through the 1990's. They came to Germany to find work, and left their families at home in places such as Yugoslavia and Turkey.

What Do They Show? Another type of event that can be traced easily on population pyramids, is the effect of war. Often this leads to large in-balances in the population, with far more women than men of fighting age remaining as the men have been killed in battle.

What Do They Show? Population pyramids can be used to help planning for the future also, as they can used to project the percentages of certain age- groups in the population over the next 50 years. In this way plans can be introduced to cope with the forecast changes, such as the ageing population in the UK.

LEDC’s Vs MEDC’s Less economically developed countries and more economically developed countries both have certain characteristics that can be seen on a population pyramid.

MEDC’s Narrow base to the pyramid, due to low BR. Constant numbers of people through all bands of working age. Large number of people over 65, which means that there is a high dependent elderly population. High life expectancy, due to good medical care, means that there is a high percentage over 65. This also means that the pyramid is taller. Low DR due to good health care. Low infant mortality rate, means that families have less children, but they usually survive to live a long life. Females tend to live longer then males.

LEDC’s Wide base to the pyramid, due to high BR. This means that there is a high dependent young population. Numbers decrease as you go up the pyramid, forming the triangular shape of the pyramid. Few people over 65, means there is a very small dependent elderly population. Low life expectancy, poor health care. High DR and infant mortality rate. Families have more children, as they are not sure how long they might survive. Females tend to live longer then males.