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Questions for Today:
• What are the different age structures of a population and how will they determine future growth?
• What are different ways to slow down population growth?
• What are the four different stages in human population growth?
• What is the number one method to curb population growth?
Age Structures
• Age structure is the distribution of males and females among age groups in a population.– Analyst plot the percentages of numbers of males and
females in age structure diagrams or pyramids
• Three types of age structures:– Prereproductive (0-14)– Reproductive (15-44)– Postreproductive (45 and older)
• Nearly 28% of the people on the planet were under 15 years of age in 2008
Age structure Diagrams
Male Female Male Female Male Female Male Female
Expanding Rapidly Guatemala
Nigeria Saudi Arabia
Expanding Slowly United States
Australia China
Stable Japan Italy
Greece
Declining GermanyBulgaria Russia
Prereproductive ages 0–14
Reproductive ages 15–44
Postreproductive ages 45–85+
Age Structures
• Age structure vary in developed countries and developing countries.– Developing countries will have a higher
percentage of people in the prereproductive ages than developed countries.
Fig. 6-9b, p. 131
Developing Countries
80–8585+
75–7970–74
Male Female
60–6465–69
55–5950–5445–49
35–39Ag
e 40–44
25–2930–34
20–24
10–1415–19
5–90–4
300 200 100 0 100 200 300
Population (millions)
Age Structures
• What happens when your pyramid is inverted?– Japan:
• Population 2008: 128 million• Population 2050: 96 million
– The Majority of Japan’s population is reaching their postreproductive ages.
Rising Death Rates
• Aside from a disproportion in the age structures, one of the major causes for population decline is AIDS and HIV.
• AIDS can affect a population by:– Lowering life expectancy– Loss of workforce
Slowing Population Growth
• Four major stages in demographic transition.– Preindustrial– Transitional– Industrial– Postindustrial
• As more developing countries move into the developed category, we will see a boom in population.
Death rate
Total population
Birth rate
Population grows rapidly because birth rates are high and death rates drop because of improved food production and health
Decreasing
Stage 2Transitional
Increasing Very high
Population growth levels off and then declines as birth rates equal and then fall below death rates
Stage 4Postindustrial
NegativeZero
Populationgrows veryslowly becauseof a highbirth rate(to compensatefor high infantmortality) and ahigh death rate
Stage 1Preindustrial
Growth rate over time
80
70
60
50
40
30
20
10
0
Bir
th r
ate
an
d d
eath
rat
e(n
um
ber
per
1,0
00 p
er
yea
r)
Low
Population growth slows as both birthand death rates drop because of improved food production, health, and education
Stage 3Industrial
Low
Methods to slowing population growth
• Family Planning– Family planning provides educational and
clinical services that help couples choose how many children to have and when to have them.
• Varies from culture to culture
– A Major Factor in reducing the number of births throughout the world
• 55% of a drop in TFR because of FP.
Family Planning
• Two problems:– Most pregnancies in developing countries are
unplanned and end with, usually, an illegal abortion.
– The lack of access to family planning services.
Family Planning
• Examples of Government Funded Family Planning:– China’s One Child Policy
• Prefer Males• Pledge to have one child, reap many benefits!
– India’s Family Planning• Government provides Information and resources,
but Couples still believe having large families is the best.
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