Survival Curves
L.O: to describe and explain the shape of the
human population survival curve
http://galen.metapath.org/popclk.html
Quick Check – What can you conclude about the
populations of these four countries?
Quick Check – What can you conclude about the
populations of these four countries?
India’s population is expanding, while China is
contracting, US appears stationary and Italy is
contracting quite quickly.
Decreasing
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What major developments affected
population size?
1. Agricultural development
2. Development of trade and manufacturing –
industrial revolution
Survival Curves
A survival curve plots the number of people alive as a
function of time. Typically it plots the percentage of a
population still alive at different ages but it can also be
used to plot the percentage of a population still alive
following a particular event, such as a medical operation or
the onset of a disease.
The average life expectancy is the age at which: 50% if the
individuals in a population are still alive.
Life expectancy can be calculated from a survival curve, by
finding this % and reading off the life expectancy.
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 Type I – applies to species that
have a high survival rate in the young.
Live out the most of their lifespan,
and die in old age.
 Type II – applies to species that
have a relatively constant death rate
throughout their lifespan. Death is
often from predation or disease.
 Type III – found in species that
have many young, most of which die
very early in their life.
 Most human populations have a
type I survival curve. Where infant
mortality is high, survival curves
approach type III.
To Do:
1. Complete the Survival Rates and Life
Expectancy worksheet
2. Draw a population pyramid for Ethiopia
3. Now compare this pyramid to the pyramid of
the UK that you have been given and answer
the questions below:
A. Is the population of Ethiopia: stable, increasing or
decreasing?
B. Is the population of the UK: stable, increasing or
decreasing?
C. What stage of the demographic transition model
(DTM) do you think Ethiopia is in? Give reasons
for your answer.
• 6 marker:
• Compare and contrast the populations of
UK and Ethiopia. (6 marks) 1 mark will be
given for QWC.
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