Chapter2 -Key Issue #3

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Transcript Chapter2 -Key Issue #3

Why is Population Increasing at Different
Rates in Different Countries?
Key Issue #3
Demographic Transition
• Demographic Transition: change in a society’s
population; because of diverse local cultural
and economic conditions, demographic
transition diffuses to individual countries at
different rates and produces local variations in
natural increase, fertility and mortality
– Process of several stages and every country is one
of them; beginning, middle, and end
• Barring a catastrophe it is irreversible
The Demographic Transition
Fig. 2-13: The demographic transition consists of four stages, which move from high birth and
death rates, to declines first in death rates then in birth rates, and finally to a
stage of low birth and death rates. Population growth is most rapid in the second
• Stage 1: Low Growth
– Lasted several hundred thousand years
– Crude Birth and death rates varied considerably
form one year to the next and from one region to
another; over long periods of time they were
comparable at high levels
– NIR was essentially zero
– Earth’s population unchanged at somewhere
around half a million
Stage 1
– Hunter and gathers
– Food easily obtained , population increased
• Population decreased when food was scarce
– 8,000 B.C. population grew by several thousand
per year
– 8000 B.C. to 1750 A.D. population increased from
5 million to 800 million
– Caused by agricultural revolution: domestication
of plants and animals and no longer relied on
hunting and gathering
8000 B.C to 1750 A.D.
Stage 1
– Created large and more stable food sources;
people survived longer
– Remained in stage 1 of demographic transition
model because food supplies were still
– Farmers prospered in certain regions with
abundant harvests and population grew
– Unfavorable climates resulted in low food
production, CDR would soar
– War and disease took its effects as well in stage 1
Stage 2
• Stage 2: High Growth
– For 10,000 years world grew at a moderate pace
– After 1750 grew ten times faster
– Occurred in late 18 and 19 centuries because
several countries moved into stage 2
– CDR plummets(falls because of new technologies),
CBR remains same as stage 1, difference in CBR
and CDR is high, NIR is high, population grows
Stage 2
– 2 PARTS:
• First Part: period of acceleration
• Second Part: growth rate slows, gap between birth and
death is high
– Countries enter stage because of Industrial
Revolution: began in England in 18th Century and
spread to the European Continent and North America
during the 19th century
• Major improvements in technology that transformed how
goods were made and the delivering of those to the market;
steam engine, mass production, powered transportation
Stage 2
– Result was unprecedented wealth , some of it
made communities better places to live
– Wealth improved farming and factory techniques
and improved sanitation and hygiene
• Sewer systems installed, food and water supplies were
protected against containments
• People healthier and lived longer
• Europe and North America diffused to stage 2 in around
1800; Africa, Asia and Latin America diffused around
the 1950s
Stage 2
– World population grew by 1.7% per year during the
second half of 20th century compared 0.5% per year
during the nineteenth century
– Medical revolution( improved medical technology)
that was started in North America and Europe allowed
for countries of Africa, Asia, and Latin America to
move into stage2 200 years later than Europe and
North America
• Eliminated many of the diseases that caused deaths in LDC’s
• Immunizations to small pox and other disease were
• Penicillin, vaccines and insecticides effectively and
inexpensively controlled infectious diseases like malaria and
Stage 3
• Stage 3:Moderate Growth
– Moves from 2 to 3 when CBR begins to drop
– CDR continues to fall in stage 3 but at a much
slower rate than in 2
– Population still grows because CBR is still higher
than CDR
– Rate of natural increase is more modest in
countries in stage 3 than in 2 because gap
between CBR and CDR is narrows
Stage 3
– European Countries and North America moved
into stage 3 during first half of 20th century
• Asia and Latin America, more recent years
• Much of Africa still in stage 2
– CBR changes because of new or different social
customs (drops)
• Fewer children
• Economic changes caused fewer offspring: live cities
instead of farms
• Urban homes are smaller
Stage 4
• Stage 4: Low Growth
– CBR declines to the point of where it equals the CDR
and NIR approaches zero
– Zero Population Growth (ZPG)
• May occur when CBR is still slightly higher than the CDR,
some females die before reaching childbearing years and the
number of females in childbearing years can vary
• To make up for differences, define ZPG as the TFR that
results in a lack of change in the total population over a long
• TFR of 2.1% results in ZPG
– Most European countries have reached state 4
– United States reached this stage around 2000
Stage 4
– Social customs help explain stage 4
• Women in the labor force
• Need child care because both parents work outside of
home- before employment and child rearing took place in
the home
• Wide range of birth-control
• Increase income and leisure time, participate in activities
and entertainment not suitable for children
• Russia has negative NIR more deaths than births
• Eastern Europe's high death rates and low birth rates are a
legacy of Communist rule
• Inadequate pollution control high death rates
• Strong family planning lower birth rates
• Deep pessimism about having children in a uncertain world
• A country that has passed through all four stages
of the model has in some ways completed a
cycle- little or no increase in stage 1, to little or no
natural increase in stage 4
• Two crucial demographic differences
1. CBR and CDRs are high 35 to 40 per 1,000 at the
beginning stage and at the end the rates are very
low 10 per 1,000
2. Total Population of the country is much higher in
stage 4 than in stage 1