Population structure. (Page 137, Understanding GCSE Geography)

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Population structure. (Page 137, Understanding
GCSE Geography)

• Learning objectives.
• To be able to construct and interpret population
  pyramids.
• To be able to link population pyramids to stages
  in the Demographic Transition Model.

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Starter.Look at the next five slides. They show
5 countries or groups of people which are at
different stages of the Demographic Transition
Model.Use the sheet to decide at which stage
they are and write them in on the spaces provided
on the sheet.
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Afghanistan.
4
Germany.
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Traditional rainforest tribes.
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Brazil.
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USA.
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A population pyramid shows the population
structure of a population. They are sometimes
called age-sex pyramids. Countries can collect
this information by a census. In the UK there is
a census every ten years.
It has horizontal bars showing the percentages or
numbers of males and females in each age group.
The age groups are usually 5 years apart e.g.
O-4, 5-9 years etc.
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The shape of a population pyramid can be used to
work out which stage in the population cycle a
country is in. Afghanistan is in Stage 2 of the
population cycle.
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France is at Stage 4 of the population cycle.
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Some pyramids have irregular shapes with bulges
or gaps at certain age groups. Bulges, i.e. where
the pyramid is fatter. are often a result of
in-migration to an area. Many cities in
developing countries have a bulge in males aged
20-40 years old as a result of the in-migration
of young males looking for work, as do mining
settlements or towns with an army barracks.
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In the UK some towns like Eastbourne have a top
heavy pyramid with more elderly people. Often
there are more women in the elderly population
because on average women have a longer life
expectancy. The top heavy pyramid is because the
town is popular as a retirement town and many
older people have moved in once they have retired
from work.
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Now do the Drawing Population Pyramids
worksheet.
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Now do the Activities 3 4 on p.137.
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• Key points for you to know for revision.
• A population pyramid shows the population
  structure of a country. It is a graph that shows
  the age and sex structure of a population.
• If it is really a pyramid shape then the
  population it shows has a high birth and death
  rate and is a developing country.
• Population pyramids for developed countries have
  a bulge at adult groups, because they have more
  older people and less children.
• Population pyramids can be drawn for any
  population, not just countries. They can be
  drawn for regions or even towns. They can tell
  us a lot about a community of any size.