3.4.1 human population growth l.o: to describe and explain the shape of the human population growth...
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3.4.1 Human Population Growth
L.O: to describe and explain the shape of the human population growth curveto explain why different countries have different growth curves
Make a note of the total human population size, as we shall see how much it increases during the lesson!
http://galen.metapath.org/popclk.html
• http://www.youtube.com/watch?v=sc4HxPxNrZ0&feature=relmfu
• http://www.bbc.co.uk/news/world-15445092
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The human population
There are currently more than 6 billion people on Earth.
The human population has grown exponentially since the industrial revolution when new technology increased the carrying capacity of the Earth.
po
pu
lati
on
(b
illio
ns
)
population growth rate
× 100=
population at end of period
– population at start of period
population at start of period
The population growth rate can be calculated by subtracting death rate from birth rate, or using the following equation:
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Demography
Demography is the study of the size and structure of populations, including a population’s age and sex distribution.
Demographic rates, such as population growth rate, birth rate and death rate can be used to describe how a population, or a subset of a population, changes over time.
A population’s demographic rates are determined by the environmental conditions. Human populations are greatly affected by their level of economic development.
population
births
immigration
deaths
emigration
Population growth rates
• For each of the locations, calculate:– Birth rate– Death rate– Population growth– Population growth rate
• What factors affect:a) birth rate?b) death rate?
Population growth ratesLocation
Population at start of year/number of
people
Gondor 131504 15232 23248 2156 278 116 177 -6138 -4.67Narnia 59874 2533 1512 2001 123 42 25 2899 4.84
Oz 3010 221 230 5 7 73 76 -11 -0.365Loompa Land 153 25 4 2 0 163 26 23 15.0King's Landing 50001566 9893251 20012890 2544 255960 198 400 -10373055 -20.7
LocationBirth rate/births per 1000 population per
year
Death rate/deaths per 1000 population
per year
Population growth/number of
people per year
Gondor 131504 15232 23248 2156 278 116 177 -6138 -4.67Narnia 59874 2533 1512 2001 123 42 25 2899 4.84
Oz 3010 221 230 5 7 73 76 -11 -0.365Loompa Land 153 25 4 2 0 163 26 23 15.0King's Landing 50001566 9893251 20012890 2544 255960 198 400 -10373055 -20.7
LocationPopulation
growth rate (%)
Gondor 131504 15232 23248 2156 278 116 177 -6138 -4.67Narnia 59874 2533 1512 2001 123 42 25 2899 4.84
Oz 3010 221 230 5 7 73 76 -11 -0.365Loompa Land 153 25 4 2 0 163 26 23 15.0King's Landing 50001566 9893251 20012890 2544 255960 198 400 -10373055 -20.7
LocationPopulation at start of
year/number of people
Gondor 131504 15232 23248 2156 278 116 177 -6138 -4.67Narnia 59874 2533 1512 2001 123 42 25 2899 4.84
Oz 3010 221 230 5 7 73 76 -11 -0.365Loompa Land 153 25 4 2 0 163 26 23 15.0King's Landing 50001566 9893251 20012890 2544 255960 198 400 -10373055 -20.7
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Demographic transition model
Demographic Transition Model
1. Complete the sheet to show the name of each stage and the causes and effects on changes in birth/death rate and natural increase.
2. Try to suggest countries that may be in each stage.
Summary – Factors affecting human population size
• Food availability – agricultural developments• Disease – healthcare, vaccinations, sanitation• New technologies/manufacturing techniques• War/natural disasters• Birth control/education• Economic conditions• Cultural/religious/political factors
Age population pyramids
Show % male and female per age group Three typical types:1. Stable population: birth rate = death rate2. Increasing population: birth rate > death rate3. Decreasing population: birth rate < death rate
Stationary
Increasing
Decreasing
Population PyramidsIn pairs, use the data to draw one of the two pyramids each.
You will need to calculate the %s first!
Compare the shapes of the two pyramids – what do they tell you about the populations?
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Population pyramids
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Survival curves measure the life spans of a sample of individuals. At each age the number of survivors is plotted.
Survival curves and life expectancy
Survival curves can also be used to determine average life expectancy. This is the age at which 50 % of the sample population is still alive.
In general, more developed countries tend to have higher survival rates. This causes their curves to sit further to the right.
age (years)s
urv
ivo
rs (
%)
00 10050
100
50
developed
developing
stone age
Survival Curves
Try the exam question…
Survival Curves
DefinitionsAge population pyramidBirth rateDeath rateDemographic transitionEmigration rateGrowth curveImmigration rateLife expectancyPopulationPopulation growth rateSurvival curve