Mexico, with a youthful population structure, has a dependency ratio of 1. The higher ratio, the greater the number of dependents that have to be provided for from the taxes on the workforce. A ratio of 1 means that for every working age person there is one dependent person. The UK had a ratio of 0. These countries have a concave profile because they have high birth rates and high death rates, plus low life expectancies.
Very few people survive to old age the average life expectancy in Sudan was 52 years in and birth rates are very high. This cause the population at the base to be prominent and grow through momentum every year, but these groups are compensated by. LEDCs have a triangular shaped pyramid. They have lots of children and people do not tend to live for a long time low Life expectancy.
These countries populations grow rapidly as many more children are added to the population than people die. The Philippines pyramid shows this perfectly and has a population growing at 1. This does not sound like a big percentage. However, when you do the math, 1.
Most MEDCs have a space rocket shape, with old people living for a long time high life expectancy , lots of workers and reasonable numbers of children. These populations are stable and are growing slowly as the number of young is just above the number of people dying. Some MEDCs actually have declining populations where there are not enough children being born each year to replace those dying. Germany is experiencing a period of negative growth As negative growth in a country continues, the population is reduced.
A population pyramid is a graph that shows the distribution of ages across a population divided down the center between male and female members of the population.
The graphic starts from youngest at the bottom to oldest at the top. It is called a population pyramid because when a population is growing there are more babies being born than there are people dying , the graphic forms the shape of a triangle. A population pyramid can be used to compare differences between male and female populations of an area. They also show the number of dependents children and, sometimes, elderly people and general structure of the population at any given moment.
There are three main trends in populations that affect the shape of a population pyramid. The first is when there are both high fertility and high mortality rates among younger members. Expansive pyramids mean that the population does not increase much in total number and has many young people. These population pyramids are wider in the middle of the graph as the population has high numbers of middle aged and elderly people, but fewer young people.
These population pyramids represent a stable population that will not change significantly barring any sudden changes to fertility or mortality rates. Population pyramids are useful for studying the future of a region as well as examining historical and current population trends.
If part of the population has been affected by sudden changes, such as casualties from armed conflict, high female mortality in childbirth, or the migration of young workers out of poorer regions, the graph will offer a way to visualize how the future population will be affected.
They can also help direct government and private industry distribution of services for regions based on population needs. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited. Tyson Brown, National Geographic Society. National Geographic Society.
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You cannot download interactives. Demography is the study of demographics, the social characteristics and statistics of a human population. This study of the size, age structures, and economics of different populations can be used for a variety of purposes.
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