Presentation on theme: "What is this trying to show? Population structures The rates of natural increase, births, deaths, infant mortality and life expectancy all affect the."— Presentation transcript:
Population structures The rates of natural increase, births, deaths, infant mortality and life expectancy all affect the population structure of a country. The population structure of a country can be shown by a population or age-sex pyramid.
Population pyramids show The total population divided into five- year age groups the percentage of people in each of those age groups the percentage of males and females in each age group
Population pyramids are useful because they show: Trends in the birth rate, death rate, infant mortality rate and life expectancy - these trends can help a country to plan its future services, e.g. more homes for the elderly if there is an ageing population or fewer schools if there is a declining birth rate. The effects of people migrating into or out of a region or country. The proportion of the population who are economically active and the proportion who are dependent upon them (dependency ratio).
Key things to know about population pyramids: The shape of a population pyramid gives us information about birth and death rates as well as life expectancy. A population pyramid tells us how many dependants there are living in an area. There are two groups of dependants; young dependants (aged below 15) and elderly dependants (aged over 65). dependants
Key things to know about population pyramids: Those of working age are classed as economically active. Dependants rely upon the economically active for economic support. economically active economically active Many LEDCs have a high number of young dependants, whilst many MEDCs have a growing number of elderly dependants.
How may a pyramid change over time? A population pyramid that is very triangular (eg Mozambique in 2000) illustrates a population with a high number of young dependants and a low life expectancy. A population pyramid that has fairly straight sides (more like a barrel) illustrates a population with a falling birth rate and a rising life expectancy.
How may a pyramid change over time? Over time, as a country develops, the shape of its population pyramid changes from a triangular shape to a barrel-like shape with straighter edges. Places that are experiencing an ageing population and a very low birth rate may have a population structure that looks a little like an upside-down pyramid.
Dependency ratios The population of a country can be divided into two categories according to their contribution to economic productivity. Those aged 15-65 years are known as the economically active or working population; those under 15 (the youth dependency ratio) and over 65 (the old age dependency ratio) are known as the non-econo mically active population.
The dependency ratio can be expressed as: children (0-14) and elderly (65 and over)x 100 those of working age http://news.bbc.co.uk/2/hi/south_asia/6911544.stm India’s dependency ratio 2008
e.g. UK 1971 (figures in millions): 13 387 + 7307 x100 = 65.45 31616 31616 So for every 100 people of working age there were 65.45 people dependent upon them
By 1999 the dependency ratio had changed to: 11 345 + 9 271 x 100 = 53.55 38 498 So although the number of elderly people had increased, this was more than offset by the larger drop in the number of children (the dependency ratio does not take into account those who are unemployed). The dependency ratio for most developed countries is between 50 and 70, whereas for less economically developed countries it is often over 100. So although the number of elderly people had increased, this was more than offset by the larger drop in the number of children (the dependency ratio does not take into account those who are unemployed). The dependency ratio for most developed countries is between 50 and 70, whereas for less economically developed countries it is often over 100.
How will the structure of population A impact on the provision of 2 social services? HSC Short Ans Due to population As structure the provision of social services is going to be difficult. There is a small working age population to support the young average population. This will make it difficult for Population A to raise enough tax revenue to provide health and education services. How will the structure of population B impact on the provision of 2 social services? Due to the ageing population structure of Population B this will impact on the provision of social services. The provision of health and aged care facilities for the ageing population will be difficult as the average age of Population B is getting older. The proportionately smaller working age population will have more dependents to support which will impact on the ability of the government to raise tax money for the provision of social services.