Transcript Chapter 15 Lessons from the Past, Lessons for the Future.

Chapter 17
Lessons From the Past, Lessons
For the Future
Lessons from the Past & for the
Future
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How Successful Are We?
Humans are animals
 Religious views
 Exploitation of resources
 Reproduction
 # of Species
 Longevity
Impact of Humans
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Culture as an adaptive strategy
Emergence of Agriculture.
Increased sedentism.
 Health & nutrition
 Infectious diseases
Where humans meant to live the lifestyles
we live today?
The Loss of Biodiversity
What is biodiversity?
 Loss of biodiversity.
 Geological record:
15+ mass extinction over
the past 570 million years.
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Mass Extinction
Events
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1st- 250 m.y.a.- climatic change-landmasses into one
supercontinent.
2nd - 65 m.y.a. ended 150 million years of evolutionary
processes that produced the dinosaurs. (impact of an
asteroid).
3rd- Occurring now-large mammalian species-pushed
toward extinction by humans (Pleistocene 10,000y.a.)
 In North America, at least 57 mammalian species
became extinct, including the mammoth, mastodon,
giant ground sloth, saber-toothed cat, several large
rodents, and numerous grazing animals
Extinction
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Species disappearing
 Reasons
 Rainforest deforestation
 Contributes to global warming- absorption of
carbon dioxide.
 Burning trees as land is cleared- +carbon dioxide.
 An estimated 20% of all carbon dioxide
emissions are accounted for by the burning of
the Amazon rain forest alone.
 Could humans become extinct?
Map of Deforestation
Overpopulation
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Main problem facing humanity
Reasons?
 10,000 years ago-about 5 million people.
 By 1650- 500 million
 By 1800- 1 billion.
 Between 10,000 years ago and A.D. 1650
population size doubled 71 times.
 50% are under 15 yrs. old
Overpopulation
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Dates and associated population
estimates up to the present are as
follows:
 mid-1800s, 1 billion
 1930s, 2 billion
 mid-1960s, 3 billion
 mid-1980s, 4 billion
 present, 6 billion
Line Graph Depicting Exponential
Growth of Human Population
The Greenhouse Effect And
Global Warming
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Activities- produce waste and pollutionenvironmental degradation.
Energy for human activities is derived
from burning of fossil fuels.
Burning fossil fuels releases carbon
dioxide into the atmosphere- traps heat.
Effects of deforestation
Results
Global Warming
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Kyoto Protocol
Since 1860- 1990s hottest decade.
2002 -the warmest year on record,1998
as second.
2003 in Europe- hottest on record.
 temperature reached 100°F in London.
Climate Change
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The average surface temperature of the earth
increased by 0.8 C (1.4F)between 1961 and
1990. (U.N. Intergovernmental Panel on Climate Change)
An increase in the mean annual temperature
worldwide of 0.5–1°C(.9-1.8 F) could result in
melting of the polar caps and flooding of coastal
areas.
Experts believe Greenland’s ice sheet will
disappear if temperatures increase 3.0°C (5.4
F).
 This could raise sea levels by as much as 23
feet over the next 1000 years.