How can we describe and explain population growth?

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How can we describe and explain population growth?
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Describing the population

• Population pyramids is a type of a histogram
  that shows the percentage of males and females in
  the population by age group or cohort.
• Variation in a pyramid shape shows variation in
  age and sex structure of the population.

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What does a pyramid looks like?

• Changes in the Canadian population. What do you
  notice?
• http//www12.statcan.gc.ca/census-recensement/2006
  /as-sa/97-551/vignettes/cda06pymd.swf -

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Predictions for Canada?
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Dependency load

• The dependency ratio tells us how many young
  people (under 16) and older people (over 64)
  depend on people of working age (16 to 64). The
  dependency ratio is worked out with this formula
• New Zealand, a developed country, has 23 of its
  population less than 15, and 12 over 65. This
  makes 65 between 15 and 64.
• What does the higher number mean?
• The higher the number, the more people that need
  looking after, but there are fewer workers and
  tax dollars.

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The demographic transition model

• Concentrates on transition from high birth and
  death rates to low birth and death rates.

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Stage I primitive stage both B and D rates are
high. Why?

• Birth rate
• Lack of family planning
• High Infant Mortality Rate
• Need for workers in agriculture
• Religious beliefs

• Death rate
• High levels of disease
• Famine
• Lack of clean water and sanitation
• Lack of health care
• War

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Stage II Birth Rate remains high. Death Rate is
falling. Population begins to rise steadily. Why?

• Death Rate is falling as a result of
• Improved health care (e.g. Smallpox Vaccine)
• Improved Hygiene (Water for drinking boiled)
• Improved sanitation
• Improved food production and storage
• Improved transport for food
• Decreased Infant Mortality Rates

• Religion and cultural norms remains strong
• No family planning

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Stage III - Birth Rate starts to fall. Death Rate
continues to fall. Population rising. Why?

• Family planning available
• Lower Infant Mortality Rate
• Increased mechanization reduces need for workers
• Increased standard of living
• Changing status of women

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• Stage IV zero growth zone B and D rates are
  both low. Population steady
• Stage V the new frontier.