3.1 Population Dynamics




Assessment 3.1.1: Describe the nature and explain the implications of exponential growth in human populations.

à Exponential growth: a growth rate which is increasingly rapid or an acculturating rate of growth
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à Impacts of exponential growth: huge amount of extra resources are needed to feed, house, clothe and look after the increasing number of people

Population growth is more common in Less economically developed countries ( LEDCs ) as they are less educated, and believe they need more children to help them make a living and take care of them in the future.
Governments have tried to reduce the population growth rate by proving health care as well as education and through policies e.g. China: One-child policy.


Assessment 3.1.2:Calculate and explain, from given data, the values of crude birth rate, crude death rate, fertility, doubling time and natural increase rate.


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à Crude birth rate: number of live births per thousand people in a population
- [total number of birth/ total population] * 1000

à Crude death rate: number of deaths per thousand people in a population
- [total number of death/total population] * 100

à Fertility rate: the average number of births per woman of child-bearing age*
*Child-bearing age= 15-49 years old


à Doubling time: the length of time it takes for a population to double in size, assuming its natural growth rate remain constant
-70/ percentage growth rate

à Natural increase rate: CBR minus CDR
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Assessment 3.1.3: Analyse age/sex pyramids and diagrams showing demographic transition models.

Population pyramids: is a structure which shows any measurable characteristic of the population; like sex, age, language, religion and occupation.
  • a wide base indicates a high birth rate
  • narrowing base suggests falling birth rate
  • straight or near vertical sides reveal a low death rate
  • concave slopes characterize high death rates
  • bulges in the slope indicate immigration or in-migration
  • deficits in the slope indicate emigration or out-migration or age-specific or sex-specific deaths (epidemics, war)
external image Benin_population_pyramid.png
For more info
http://yesitsyomoma.wordpress.com/2011/03/28/revision-topic-3-1-population-dynamics/


Demographic Transition Model:
  • Stage 1-2: LEDC, e.g. Afghanistan
  • Stage 3: MEDC, China
  • Stage 4: MEDC, Australia
  • Stage 5: MEDC, Japan
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http://geographyfieldwork.com/DemographicTransition.htm (Further reading)


Assessment 3.1.4: Discuss the use of models in predicting the growth of human populations

TO BE CONTINUED