8.1 Flashcards
What are Demographics?
Demographics is the study of the dynamics of population change.
What is CBR + Formula
Crude Birth Rate (CBR) → Number of births per thousand individuals in a population per year.
Formula: Divide number of births by the population size and multiply by 1000
Low Income countries have Higher CBR
What is CDR + Formula
Crude Death Rate (CDR) → Number of deaths per thousand individuals in a population per year.
Formula: Divide number of deaths by the population size and multiply by 1000
What is TFR
Total Fertility Rate (TFR) → Fertility rate is the number of births per thousand women of child-bearing age. It is the average number of children each woman has over her entire lifetime.
The TFR is decreasing, however in low income countries it is still very high (3-6 per woman)
The TFR has severely dropped in MEDC (2 per woman) but it still exceeds 6 per woman in African countries.
What is DT + Formula
Doubling Time (DT) → Time in years that it takes for a population size to double in size.
A NIR of 1% will make a population double in size in 70 years, thus
Formula: 70/NIR
Populations in LEDCs are doubling faster
What is NIR + Formula
Natural Increase Rate (NIR) → The rate of human growth expressed as a percentage per year (migration is ignored)
Formula: CBR - CDR / 10
Factors that lead to an lower DR
The agricultural revolution led to higher yields & healthier, more varied diets
Improvements to medicine & medical care
Improvements to technology & transport, leading to a wealthier population which increases life expectancy
Improved housing & sanitation
Birth rates remain high in LEDCs due to
Lack of access to family planning & contraception
An increase in women surviving childbirth
Families continuing to have large numbers of children to look after their parents in old age & to help support the family
Culture of having larger families which takes many years to change
Religious reasons
The birth rate has fallen significantly in many MEDCs due to
Increased access to family planning & contraception
Changing social norms which include starting families later, having fewer children, or remaining single
Increased costs of child rearing & university education
How to analyze an age-gender pyramid
- width tells us birth rate
- height tells us the life expectancy
- steepness tells us the death rates
What is the Demographic Transition Model
The DTM is a model which shows how a population transitions from a pre-industrial stage with high CBR and CDR to an economically advanced stage with low or declining CBR and low CDR.
STAGE 1
Birth Rates and Death Rates are high and variable
Population Grows very Slowly, fluctuating at times and even declining
No countries, only some indigenous tribes still at this stage.
Pre industrial LEDC
Why high birth rates?
Parents want children for labour, to look after them in old age, to continue
the family name, to replace other children who have died.
Why high death rates?
People die due to disease, famine, poor hygiene and little medicine.
STAGE 2
Birth rate remains high as the social norms governing fertility take time to change.
The death rate starts declining rapidly. The essential cause factors for this are: better nutrition, improved public health, particularly in terms of clean water supply and efficient sewage systems; and medical advances.
Population growth is rapid.
Afghanistan and Sudan are at this stage.
Early expanding LEDC
STAGE 3
Birth rate starts declining → Access to contraception, improved healthcare and education.
Desire for material goods and low IMR means people have smaller families.
Death rates remain low
Population growth continues but at a smaller rate
Brazil and Argentina are at this stage
Country becomes more developed
STAGE 4
Birth rates and death rates are low and variable.
Population growth is slow and fluctuates over time.
Most MEDC are at this stage
Industrialized countries
Stable Population sizes
