Demographic Transition

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VCE and IB Geography
The Demographic Transition Model
A Simple explanation of how it works
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What is the basic idea?

• The demographic transition model seeks to
  explain the transformation of countries from
  having high birth and death rates to low birth
  and death rates. In developed countries this
  transition began in the eighteenth century and
  continues today. Less developed countries began
  the transition later and are still in the midst
  of earlier stages of the model.

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CBR and CDR

• The model is based on the change in crude birth
  rate (CBR) and crude death rate (CDR) over time.
  Each is expressed per thousand population. The
  CBR is determined by taking the number of births
  in one year in a country, dividing it by the
  country's population, and multiplying the number
  by 1000. In 1998, the CBR in the USA is 14 per
  1000 (14 births per 1000 people) while in Kenya
  it is 32 per 1000. The crude death rate is
  similarly determined. The number of deaths in one
  year are divided by the population and that
  figure is multiplied by 1000. This yields a CDR
  of 9 in the U.S. and 14 in Kenya.

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Demographic Transition Model
Stage A / 1 Both high birth rates and death rates
fluctuate in the first stage of the population
model giving a small population growth (shown by
the small total population graph).
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Demographic Transition Model
Stage B / 2 Birth rates remain high, but death
rates fall rapidly causing a high population
growth (as shown by the total population graph).
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Demographic Transition Model
Stage C / 3 Birth rates now fall rapidly while
death rates continue to fall. The total
population begins to peak and the population
increase slows to a constant.
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Demographic Transition Model
Stage D / 4 Both birth rates and death rates
remain low, fluctuating with 'baby booms' and
epidemics of illnesses and disease. This results
in a steady population.
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Demographic Transition Model
Stage E / 5? A stage 5 was not originally thought
of as part of the DTM, but some northern
countries are now reaching the stage where total
population is declining where birth rates have
dropped below death rates.
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Population Pyramid Model
The PPM - 'Population Pyramid Model' shows how
dynamic (subject to change) population is. The
model is structured to show 'snapshots' of a
population at four points during its development,
which are shown as Stages 1 - 4 (A - D). A
country will progress through the stages.
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Case Study of Population Change Over Time - DTM
and Pyramids for UK (1780 - present)