What is the demographic transition model?
The demographic transition model (or population cycle) shows population change over time. It studies how birth rate and death rate affect the total population of a country
Population graph - Population in recent centuries
- Population reached 7 billion in 2015
- Increase of 80mil per year or roughly 1.5mil per week
- Population did not increase at this rate in earlier centuries
- World’s population fluctuated (going up and down)
- Graph indicates population fluctuates
- Since 1900s, experienced population explosion
- More babies surviving to become adults and have children of their own
- Population increase is more focused in developing countries. Countries in Africa, Asia and Latin America are seeing population increase
- Developed world - experiencing population decrease
Stage 1 of the demographic transition model
Eg. Isolated tribal troups
- Birth & death rate fluctuating
- Population does not grow because of high death rates cancelling out high bight rates
- Causes of death rate are famine, disease, natural disasters
Stage 2 of the demographic transition model
Eg. Mali
- Countries have started to develop their economies
- Governments providing clean water + health services
- Birth rate is high while death rate declines
- Population grows
Stage 3 of the demographic transition model
Eg. Brazil
- Advanced economic development
- People more educated
- Parents plan family size and have fewer children
- Less population growth
Stage 4 of demographic transition model
Eg. Ireland
- Countries are wealthy
- Parents plan families
- Low birth and death rate
- Most survive to old age
- Low population growth
Stage 5 of demographic transition model
Eg. Germany
- Death rate greater than birth rate
- Most of population is elderly and mothers have few children
- Population decline
Causes of population change
Birth rate
Number of babies born per 1000 people in a year
Death rate
Number of deaths per 1000 people in a year
Migration
The movement of people in and out of an area
Calculating natural increase/decrease
Births per 1000 - Deaths per 1000 = ______ / 100 = __ %
Eg. natural increase
Eg. Ireland
Birth rate: 17 per 1000
Death rate: 6 per 1000
17 - 6 = 11
11/100 = 1.1%
Natural decrease example
Eg. Japan
Birth rate 8 per 1000, death rate 10 per 1000
8 - 10 = -2
-2/100 = 0.2%
Factors influencing the rate of population
Food supply War Technology development Health Education The status of women
Factors influencing the rate of population: Food supply
Growing populations need expanding food supplies.
The agricultural revolution made food more available.
Machinery, crop rotation, and selective breeding increased food supply. Fertilisation enable crops to be grown which reduced the chance of famine.
Factors influencing the rate of population: War
Initially, war increases the death rate.
Young people leave for war which reduces the birthrate.
War strains food supplies, farming, healthcare and water supplies.
After war young people return and there may be a baby boom which happened in Germany after WW II
Factors influencing the rate of population: Technology development
Technological development increases food supply as a result of machinery.
This makes farming more productive.
Irrigation schemes allow crops to be grown in times of frought.
New drugs increase population health.
Factors influencing the rate of population: Health
Healthcare systems decrease the death rate.
Vaccines and antibiotics provide immunity to diseases.
Certain diseases are eradicated in developed countries whereas they may be widespread in developing countries.
Access to clean water, sanitation and good living conditions reduce spread of diseases. Eg. Ireland
Factors influencing the rate of population: Education
Education reduces the birth and death rate.
The more educated the population, the smaller the families and lower the population growth.
When parents see that their children are surviving to adulthood, they have fewer children.
Birth rates are low in developed countries because people are more educated and raising a large family is more expensive.
Factors influencing the rate of population: The status of women
Back then women were confined to roles of mothers and full-time homemakers
Today women have more options, Many pursue a career and plan their families.
Feminist movement in 1960s along with high levels of female education brought this change.
In developing countries, mothers have more traditional roles. They have lower statues and do not have access to family planning.
What are population pyramids
Tell us about birth rates, death rates, life expectancy and dependancy.
What is population structure?
Means the ‘make up’ or composition of a population.
Looking at the population structure of a place shows how the population is divided up between males and females of different age groups.
Population pyramids base and top
Broader base = higher birth rate
Narrower the top = higher death rate
What does a population pyramid tell us?
How many dependants there are.
Dependants rely on economically active people. (People who can work)
Two groups of dependants
young dependants (below 15)
elderly dependants (over 65)
What does being dependent mean?
Being dependent means you rely on people.
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Secondary economic activities38
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Planets3
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