Unit 1.2: How and why do populations change naturally?

for geog as level.


Factors affecting mortality rates

DEMOGRAPHIC: Population structure - 'Greying' or aging populations, e.g. Italy and Germany.

ECONOMIC: Widespread proverty and poor living conditions.

SOCIAL/CULTURAL: Lack of exercise or sedentary lifestyle. Smoking, drinking or drug use. Take inoculations where avaliable. Education makes people aware of health risks. Education of healthy living. Increased medical research.

POLITICAL: Policies to improve access to education and healthcare. 

ENVIRONMENTAL: Too cold - hypothermia risk - e.g. Britain most winters. Too hot - Heat exhaustion e.g. France, August 2004. Natural hazards - tsunami/floods/tectonic hazards/extreme weather events. Danger of urban environments - crime/industrial/road accidents.

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Factors affecting fertility rates - Demographic


High infant mortality rates

  • Families often try to compensate for high infant child mortality by having a large number of children.
  • This is in the hope that some of the children will survive and reach adulthood.
  • In Africa (2000) a woman must have 10 children to have a 10% chance of survival.

High proportion of people living in the reproductive age range

  • Girls often get married young, as they can start to reproduce from 12 years.
  • A higher population means a higher rate of births leading to a population increase.
  • Those surviving can reach the reproductive age range.
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Factors affecting fertility rates - Economic


Children regarded as economic asset (producers)

  • Viewed as producers rather than consumers.
  • Parents will encourage them to contribute to the family income.
  • Parents will encourage their children to have a large family as it could make for money for the family.
  • The children can look after the elderly.
  • They can be used for home/agricultural work for the family.
  • E.g.Sub Saharan Africa, Asia and Latin America.

Children regarded as financial burden (consumers)

  • It costs a lot of money to raise a child.
  • E.g. approx $100,000 from birth to 18 years old.
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Factors affecting fertility rates - Social/Cultura



  • More women are more career driven - this means that children are born later, so as a women's fertility rate ends around 45 years, they will have less children.
  • Low literacy rates and drop of fertility rates.

Security in old age

  • Many families have many children in the hope that they will look after them at an old age, as they don't get pensions. E.g. in Africa.

Religion (use of contraception/age and type of marriage)

  • Some religions e.g. Jewish people, do not approve of using contraception.
  • This can lead to high fertility and birth rates. 
  • Catholics. 
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Factors affecting fertility rates - Social/Cultura

Status in community

  • To have a lot of children is regarded to have a high status in community. 
  • E.g. Fai Mankoh has 6 wives and 36 children!
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Factors affecting fertility rates - Political


Inducements and concessions offered to large families (pro-natal policies)

  • Government can encourage families to have children. E.g. France. This will increase the birth rates of that country.

Anti-natal policies

  • The one child policy. E.g. China.
  • Enforcement of sterilization
  • Encourage abortions.


  • Post war 'baby boom'
  • During war there was a low birth rate.
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Population pyramids

  • Population pyramids are graphs that show the age structure of a population by age and gender.
  • Normally males are of the left and females are on the right.
  • Age categories are in 5 year increasing intervals labelled up the centre axis.
  • The horizontal axis is measured in millions
  • Expansive or expanding population pyramids have a triangular/pyramid shape. The wide base indicates a high birth rate and the narrow top indicates a narrow top indicates a high death rate.
  • Stationary or stable population pyramids have a 1/2 ellipse shape. The base of this is similar in width to the population of reproductive ages which indicates a stable population.
  • Contractive or contracting population pyramids have a narrower base than the reproductive age population. This indicates a decreasing population trend. The low birth rate is indicative of a well-developed country.
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Population structure

STAGE 1: High birth rate, rapid fall in each upward age group due to high death rates. Short life expectancy.

STAGE 2: Still as high birth rate. Fall in death rates as more living in middle age. Slightly longer life expectancy.

STAGE 3: Declining birth rate, declining death rate, more people living to an older age.

STAGE 4: Low birth rate, low death rate, higher dependency ratio, longer life expectancy.

The dependency ratio can be shown by calculations. It is the ratio between those in the non-economically active age group and those in the economically active age group.

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Case study: Italy

Demographic structure:

  • Life expectancy at birth is rising
  • Life expectancy at 65 rising
  • Fertility rising by 1.2%

Italy will face a much greater percentage of its population being inactive, reflected by over 45%+ increase in the total dependency ratio and an 85% rise in old age dependency rates between 2000 and 2030.

What do the italian government need to do?

  • Rising retirement age
  • Encouraging a higher birth rate
  • Reducing less use of contraception

In 2003, Robert Maroni, offered 1000 Euros to every woman who had a second child. This was paid to 190,00 people and was extended to people who had a first child too. Rocco Falivena, gave 10,00 euros to increase the birth rate also.

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The Demographic Transition Model


  • Offers good description of general trends.
  • Provides basis for comparison between countries
  • Predictive for fertility rates
  • Attempts to offer explanation of transition changes
  • Has provided a starting point for more sophisticated models.


  • Derived from a limited database - European countries only eurocentric view that all countries would pass through the same four stages. In reality many countries especially in Africa will never become industrilised.
  • Does not predict total population numbers for a country, as migration is not included.
  • Causes in decline of birth rates not wholly understood
  • Impact of external influences from other countries not concerned.
  • Does not predict when transitions will occur, length of stay.
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Validity of the DTM: Europe and LEDC's


  • Suggest fertility decline is even - European countries do vary.
  • Suggests fertility decline is linked to increase in literacy urbanisation and decreases in mortality.
  • Ignores birth control in stage 1.


  • The transition in fertility and mortality occurs in a shorter time.
  • Growth of population is greater in LEDC's
  • Comparisons with MEDC's because of the above^ are difficult.
  • DR's have fallen faster and for different reasons than Europe.
  • Mass contraceptive availability.
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