A countrys stage of demographic transition gives it a distinctive population structure Population in a country is influenced by the demographic transition in two important ways of pop in each age group ID: 784781
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Slide1
Why Is Population Increasing at Different Rates?
A country’s stage of demographic transition gives it a distinctive population structure.
Population in a country is influenced by the demographic transition in two important ways:
% of pop in each age group
Distribution of males and females
Slide2Why Is Population Increasing at Different Rates?
Population pyramids-p.62-63
A bar graph showing a place’s age and sex composition
Shape of the pyramid is determined mainly by the CBR
Age distribution
Dependency ratio
-# of people too young or too old to work, compared to # of people in their productive years.
Sex distribution
Sex ratio
-# of males per 100 females in the pop.
Slide3Population
Pyramids
See p.64
Figure 2-16
Slide4Percent of Population under 15
Fig. 2-15: About one-third of world population is under 15, but the percentage by country varies from over 40% in most of Africa and some Asian countries, to under 20% in much of Europe.
Slide5Why Is Population Increasing at Different Rates?
Countries are in different stages of the demographic transition
Three examples:
Cape Verde = High growth
Stage 2 since the 1950s
Chile = Moderate growthStage 3 since the 1960s Denmark = Low growth
Stage 4 since the 1970s
Slide6Rapid Growth in Cape Verde
Fig. 2-17: Cape Verde, which entered stage 2 of the demographic transition in about 1950, is experiencing rapid population growth. Its population history reflects the impacts of famines and out-migration.
Slide7Moderate Growth in Chile
Fig. 2-18: Chile entered stage 2 of the demographic transition in the 1930s, and it entered stage 3 in the 1960s.
Slide8Low Growth in Denmark
Fig. 2-19: Denmark has been in stage 4 of the demographic transition since the 1970s, with little population growth since then. Its population pyramid shows increasing numbers of elderly and few children.
Slide9Why Is Population Increasing at Different Rates?
Demographic transition & world population growth
Most countries = stage 2 or stage 3 of the Demographic Transition
Stages 2 and 3 are characterized by significant population growth
No country is in stage 1 of the demographic transition
It is easier to cause a drop in the CDR than in the CBR
Slide10Key Issue 4
Why Might the World Face an Overpopulation Problem?
Slide11Why Might Overpopulation be a Concern?
Thomas Malthus on overpopulation:
One of the first to argue that the world’s rate of population increase was far outrunning the development of food supplies.
An Essay on the Principle of Population
(1798): Population grows geometrically while food supply grows arithmetically
Slide12Why Might Overpopulation be a Concern?
Neo-Malthusians:
Argue that 2 characteristics of recent population growth make Malthus’s thesis even more scary than it was 200 years ago:
Malthus failed to predict that LDCs would have the most rapid pop growth because of medical technology not wealth
World pop is not only exceeding food production, but other resources, like clean air, suitable farmland, and fuel
Slide13Criticism of Malthus includes the following:Pessimistic viewpoint
Ideas based on a belief that the world’s supply of resources is fixed rather than expanding.
Failure to consider technological innovation
Larger pop could stimulate economic growth
Marxist critique
Argue that issues like poverty, hunger, and social welfare problems are due to unjust social and economic institutions, not pop growth
Why Might Overpopulation be a Concern?
Slide14Malthus: Theory & Reality
Figure 2-25
Slide15Food and Population, 1950–2000
Malthus vs. Actual Trends
Fig. 2-20: Malthus predicted population would grow faster than food production, but food production actually expanded faster than population in the second half of the twentieth century.
Slide16Why Might Overpopulation be a Concern?
The NIR only declines for 2 reasons: lower CBR or higher CDR.
Declining birth rates
Reasons for declining birth rates:
Reliance on economic development
Improving local economic conditions, including education and health careDistribution of contraceptivesReducing birth rates with contraception
Opposition for religious and political reasons
Slide17Crude Birth Rate Decline,
1981–2001
Fig. 2-21: Crude birth rates declined in most countries between 1981 and 2001 (though the absolute number of births per year increased from 123 to 133 million).
Slide18Family Planning
Figure 2-22
Slide19Why Might Overpopulation be a Concern?
World health threats
The epidemiologic transition
Stage 1: Pestilence and famine
The Black Plague
Pandemics
Slide20Why Might Overpopulation be a Concern?
World health threats
The epidemiologic transition
Stage 2: Receding pandemics
Cholera and Dr. John Snow
Slide21Cholera in London, 1854
Fig. 2-23: By mapping the distribution of cholera cases and water pumps in Soho, London, Dr. John Snow identified the source of the waterborne epidemic.
Slide22Why Might Overpopulation be a Concern?
World health threats
The epidemiologic transition
Stage 3: Degenerative diseases
Most significant: Heart disease and cancer
Stage 4: Delayed degenerative diseasesMedical advances prolong life
Slide23Why Might Overpopulation be a Concern?
World health threats
The epidemiologic transition
A possible stage 5: Reemergence of infectious diseases?
Three reasons why it might be happening:
Evolution of diseasePovertyImproved travel
Slide24Tuberculosis Death Rates, 2000
Fig. 2-24: The tuberculosis death rate is a good indicator of a country’s ability to invest in health care. TB is still one of the world’s largest infectious-disease killers.
Slide25SARS Infections in China, 2003
Fig. 2-25:
China had 85 percent of the world's SARS cases in 2003. Within China, the infection was highly clustered in Guangdong Province, Hong Kong, and Beijing.
Slide26HIV/AIDS Prevalence Rates,
2002
Fig. 2-26: The highest HIV infection rates are in sub-Saharan Africa. India and China have large numbers of cases, but lower infection rates at present.