GEOG 1HB3 Lecture Notes - Lecture 6: Sub-Saharan Africa, Population Ageing, Population Pyramid
20 May 2018
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POPULATION DYNAMICS
Globally, population is understood with reference to two factors: fertility and mortality.
Pfinal = Pinitial + (B – D) P – population, B- births, D-deaths
Regionally though, population is also influenced by population movement: Migration (immigration &
emigration)
Pfinal = Pinitial + (B – D) + (I – E) I – immigration, E -emigration
FERTILITY
Some measures of fertility include:
1. Crude Birth Rate (CBR): total number of live births for every 1000 living in that population.
CBR = # B
P∗
True Fertility:
• Number of women in the population
• Number of women of child-bearing age (15-49)
CBR is not very aurate eause it doest take ito osideratio true fertilit. CBR is quite high in
Africa than in other areas
2. General Fertility Rate (or fecundity) (GFR): total number of live births per 1000 women in their
reproductive years.
GFR = # B
# w − y−9∗
3. Total Fertility Rate (TFR): the average number of children a woman will have in her fecund
years. Global TFR = 2.5 as of 2015, with total fertility rates less than 2 in MDW and greater than
2 in LDW.
Replacement level (the number of children given birth to, to replace their parents) is about 2.1.
Many factors influence the rates of fertility, some include: age, nutritional well-being, level of economic
development, & culture, etc. Regions in Africa have high fertility rate compared to places like Canada,
Russia where birth rate is below replacement levels.
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MORTALITY
We can measure mortality rates with:
1. Crude Death Rate (CDR): the number of people that died per 1000 people in a population.
CDR = # D
P ∗
CDR is not a very accurate measure of mortality because it does not take into account when
(what age) deaths occurred – do more deaths occur in younger or older population?
2. Infant Mortality Rate (an adjusted rate) (IMR): the number of deaths per 1000 live births of
children under one year of age.
IMR = # −
# ∗
3. Life Expectancy: the average number of years of life. Range is from the low 40s to more than 80.
Areas with low life expectancy include Sub-Saharan Africa while core countries have higher life
expectancy.
Many factors influence the level of mortality, some include: the age of population, access to health-care
services, economic circumstances, environmental conditions, etc.
POPULATION NATURAL INCREASE
Rate of Natural increase (RNI): measures the rate of population growth by subtracting the CDR from the
CBR. RNI does not take migration into consideration.
RNI = CBR –CDR
Doubling time: the number of years required for a population to double in size; assuming
constant RNI. Minor variations in RNI can significantly change doubling time
The current global population growth rate is ~1.2% (doubling time of 54 years)
Natural Increase:
• High natural increase: Areas with high fertility rates and low mortality rates experience
high natural increase. Countries like e.g. Guinea Bissau, Burkina Faso, etc. have high
natural increase.
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find more resources at oneclass.com
Document Summary
Globally, population is understood with reference to two factors: fertility and mortality. Pfinal = pinitial + (b d) p population, b- births, d-deaths. Regionally though, population is also influenced by population movement: migration (immigration & emigration) Pfinal = pinitial + (b d) + (i e) i immigration, e -emigration. Some measures of fertility include: crude birth rate (cbr): total number of live births for every 1000 living in that population. (cid:883)(cid:882)(cid:882)(cid:882: number of women in the population, number of women of child-bearing age (15-49) Cbr is not very a(cid:272)(cid:272)urate (cid:271)e(cid:272)ause it does(cid:374)(cid:859)t take i(cid:374)to (cid:272)o(cid:374)sideratio(cid:374) true fertilit(cid:455). Africa than in other areas: general fertility rate (or fecundity) (gfr): total number of live births per 1000 women in their reproductive years. # (cid:2925)(cid:2916) b(cid:2919)(cid:2928)(cid:2930)(cid:2918)(cid:2929: total fertility rate (tfr): the average number of children a woman will have in her fecund years. Global tfr = 2. 5 as of 2015, with total fertility rates less than 2 in mdw and greater than.
