Transcript Human Populations

Human Populations
Ch 9
https://www.youtube.com/watch?v
=4BbkQiQyaYc
 Past 200 years grown exponentially
– Expand to new areas
– Agriculture
– Sanitation, antibiotics, vaccines, fossil fuels
 1.23% growth rate (2.4 people every time your
heart beats)
 Reached 7 billion on October 31, 2011
 http://www.census.gov/main/www/popclock.html
 2050 est. reach 7.2 – 10.6 billion
 Developed countries (MDC)
– Highly industrial
– High GDP (gross domestic product) – annual market
value of all goods/services
– Growth 0.1% per year
 Developing countries (LDC)
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Low to mod. Industrialization
Low to mod. GDP
Growth 1.5% per year
Most Africa, Asia, and Latin America
Factors Affecting Population Size
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# births (fertility)
# deaths (mortality)
Migration
Population change = (b+i) – (d+e)
Demographers use:
– Birth rate (crude birth rate) - # live births per
1000 people in a particular area
– Death rate (crude death rate) - # deaths per
1000 people in a particular area
 China
 and India 37%
 US 4.5%
 Fertility = # children born to a woman during
her lifetime
 2 Types of Fertility Rates
– 1. Replacement level - # children a couple has
to replace themselves
– 2.1 (MDC) and 2.5 (LDC)
– Still world pop. would continue to grow for 50
more years (due to future parents)
– 2. Total fertility rate (TFR) – ave. # children a
woman typically has during her reproductive
years
– Global 2.7
– MDC 1950 2.5 now 1.6
– LDC 1950 6.9 now 2.9 (still above 2.1)
US. Population
 1900 76 million – 2006 299 million
 1945 – 1964 baby boom +79 million
 1965 – 1977 baby bust
– Delayed marriage
– Contraception
– Abortion
 56% growth due to births
 44% growth immigration
 Largest ecological footprint
 1905
– 3 leading causes of death
 Pneumonia
 TB
 Diarrhea
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90% US doctors no college edu.
1 in 5 adults illiterate
Daily wage 22 cents per hour
9000 cars on roads
144 mi. paved roads
3 min. phone call from Denver to NY $11
30 people lived in Las Vegas
Most women washed their hair 1 time per week
Factors Affecting Death Rates
 Declining death rates
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Increased food supplies
Better nutrition
Advances in medicine
Improved sanitation
Safer water supplies
 Has led to: lower premature death rates due to
less illness and disease
– Rapid growth rate due to low death rate especially in
developing countries
– https://www.youtube.com/watch?v=jbkSRLYSojo
2 indications of overall health of a
country
 Life expectancy
– 1955 – 2006 global (48yrs – 67yrs) 77 in MDC and 65
in LDC
 US 47yrs – 78yrs (82 by 2050)
 Poorest countries currently 49yrs or less
 Infant mortality rate–children who die before age 1
– 1965 – 2006 global: MDC 20 – 6.3
LDC 118 – 59
– 7.6 million die of preventable causes
– US 1900 (165) – 2006 (6.7) due to inadequate health
care for poor, drug addiction, high birth rate among
teens
Factors that affect birth rate
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1) importance of children in labor force (LDC)
2) cost of raising children - $250,000
3) availability of pension systems – red. need for
support by kids
4) urbanization – better access to family
planning
5) edu. and employment opportunities for
women
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Ex: Brazil literate women 2 children
illiterate women 6 children
6) Infant mortality rate
 7) age at marriage ( 25 years or older =
fewer kids)
 8) availability of legal abortions
 9) availability of reliable birth control
 10) religious beliefs/traditions/cultural norms
Age structure
 = distribution of males and females in each
age group in the world’s population
 Prereproductive – (0 – 14)
 Reproductive – (15 – 44)
 Postreproductive – (45 and up)
Pyramids
Demographic transitions
 As countries become industrialized tend to go
through 4 stages:
 Preindustrial – BR and DR about the same,
population stable
 Transitional –BR remains high, death rates drop
as living conditions improve
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Runaway population growth in this stage
 Industrial- BR and DR about the same, pop
growth slows
 Postindustrial- BR drops below death rate,
dropping population