3.4.1 human population growth make a note of the total human population size, as we will see how...
TRANSCRIPT
3.4.1 Human Population Growth
Make a note of the total human population size, as we will 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
BBC 7 Billion and You – What’s Your Number?
www.bbc.co.uk/news/world-15391515
• On your mobile (if you can)…• What number person were you on earth?• What is the current UK population?• How many people have been born whilst you
were on this website?
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The human population
There are currently more than 7 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
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Write definitions for the following terms:
Population
Birth rate
Death rate
Immigration rate
Emigration rate
Population growth rate
10 minutes
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
Now try the exam questions
3.4.1 Human Population Growth
How big is the human population now?
http://galen.metapath.org/popclk.html
Review of exam question from last lesson:
3.4.1 Human Population Growth
Aims:- Learn about the demographic transition model for human
population development- Learn how to interpret age-population pyramids- Practise your note-making and independent study skills!
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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
Demographic Transition Model
Shows how the birth/death rates and the total population change in a population that is becoming more developed.
5 main stages, starting with the least developed population.
Task• Read the information on the posters.
• Try to decide on the order in which they would feature in the demographic transition (least → most developed)
• Sketch a graph to show the changes in birth rate, death rate and total population size.
• Explain why the birth and death rates change and describe what happens to the total population as a result.
• Compile a list of factors affecting birth/death rates.
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Demographic transition model
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
Discussion – Suggest why:
• Stage 2 of the DT model happens much more quickly for countries now than it did when the UK was at that stage.
• Some countries progress to Stage 5, whilst others remain in Stage 4.
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
Stable/Stationary
Increasing
Decreasing
The trick is to link these pyramids to the stages of the demographic transition.
On the next slide, match each of the pyramids to the relevant stage of the DT.
Extension: suggest a country for each pyramid.
Now try the exam questions.
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