Transcript Demographic Transition

What do
you think
these
cartoons
are saying?
J. Gathorpe-Hardy
Hanel, Germany
Population Change
Outputs
Inputs
Births
Natural Increase
Deaths
Total
Population
Immigrants
Migration
Emigrants
The total population of an area is the balance between 2
forces of change: natural increase and migration
Natural increase is the balance between birth rates and death
rates
World Population
Changes
Global Natural Increase
Doubling Time
This map shows how long it will take for countries to double
their population if it continued to grow at the present rate
Demographic Transition
Model
Stage 1
Natural
Increase
In Population
Stage 2
Stage 3
Stage 4
Total
Population
Natural
Decrease
In Population
Birth
Birth Rate
Rate
Death Rate
Stage 1
High Fluctuating
• Low population
Stage 1
Birth Rate
– Increasing very
slowly
Death Rate
Total
Population
•
•
•
•
High birth rate
High death rate
Ethiopia/Niger
UK: pre-1780
Reasons for Stage 1
High Fluctuating
Stage 1
Birth Rate
Death Rate
Total
Population
• Little access to birth control
• Many children die in infancy
so parents have more to
compensate
• Children are needed to
work on the land
• Some religions encourage
large families
• Death rates are high due to
disease, famine, poor diet,
poor hygiene, little medical
science
Stage 2
Early Expanding
Stage 2
Birth Rate
Total
Population
Death Rate
• Population growing
at faster rate
• High but decreasing
birth rate
• Decreasing death
rate
• Sri Lanka/Bolivia
• UK: 1780-1880
Reasons for Stage 2
Early Expanding
Stage 2
Birth Rate
Total
Population
Death Rate
• Improvements in medical
care
• Improvements in sanitation
and water supply
• Quality and quantity of food
produced improves
• Transport and
communications improve
movements of food and
medical supplies
• Decrease in infant mortality
Stage 3
Late Expanding
Stage 3
Total
Population
Birth Rate
Death Rate
• Population, still
increasing, but rate
of increase slowing
down
• Decreasing birth rate
• Low death rate
• Uruguay/China
• UK: 1880-1940
Reasons for Stage 3
Late Expanding
Stage 3
Total
Population
Birth Rate
Death Rate
• Increased access to
contraception
• Lower infant mortality rates so
less need for bigger families
• Industrialisation and
mechanisation means fewer
labourers required
• As wealth increases, desire for
material possessions takes over
the desire for large families
• Equality of women means they
can follow a career rather than
just staying at home
Stage 4
Low Fluctuating
Stage 4
Total
Population
Birth Rate
Death Rate
• High population,
almost stable
• Low birth rate
• Low death rate
• Canada/USA
• UK: post-1940
Reasons for Stage 4
Low Fluctuating
Stage 4
Total
Population
Birth Rate
Death Rate
• Rates fluctuate with ‘baby
booms’ and epidemics of
illnesses and diseases
• Reasons for Stage 4 have
improved and it stabilises
Demographic Transition
Model
Stage 1
Stage 2
Stage 3
Stage 4
Total
Population
Natural
Increase
In Population
Natural
Decrease
In Population
Birth Rate
Death Rate
Ethiopia/
Niger
UK:
pre-1780
Sri Lanka/
Bolivia
UK:
1780-1880
Uruguay/
China
UK:
1880-1940
Canada/
USA
UK:
Post-1940
Is there a Stage 5?
?
?
?
Stage 5: Depleting Population
Problems
• What problems do you think there could be
with the model?
• It does not include the influences of migration
• It assumes that all countries will go through
the same pattern
• There is no time scale
• Reasons for birth rates and death rates are
very different in different countries
• And finally, is there a stage 5?
The
End?
Population Pyramids
• The population structure of a country is how it is
made up of males and females of different ages.
• The common method to show the structure is by a
population pyramid.
• This diagram is made up by putting two bar graphs
(one for male, one for female) side by side.
• From this you can read off what percentage of a
population is of a certain gender and age range.
Developing Countries
• This population pyramid is
wide at the base, which
means there is a large
proportion of young people
in the country.
• It tapers very quickly as you
go up into the older age
groups, and is narrow at the
top.
• This shows that a very small
proportion of people are
elderly.
Developed Countries
• This shape is typical of a developed country.
• It is narrow at the base, wider in the middle, and stays quite
wide until the very top, as there is a sizable percentage of older
people.
• Note that there are more old women than men.
Ever-Changing
Populations
UK Population – 1995-2050
Different
Population Pyramids
Stage 2
Stage 3
Stage 4
Stage 5
Population Sketches
Stage 2
Stage 3
Stage 4
Stage 5
Urban v. Rural Structures
Differences between
Models
Demographic Transition
Model
Population Pyramid
Model
•Drawn as a line graph
•Doesn't show male and female
populations
•Shows total population as a
separate line
•Gives details of countries in
stages
•Shows the relationship
between birth and death rates
and how these affect total
population
•Only one diagram necessary
to show all stages
•Drawn as a bar graph
•Shows male and female
population proportions
•Total population is shown as
the total area of the graph
•Shows greater detail about the
populations at each stage
•4/5 diagrams necessary to
show all stages
Population Pyramid for
…?…