Human Impact on Ecosystems

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Human Impact on Ecosystems Chapter 16
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Industrial Revolution
Human society harnessed and created the very
energy required to run life processes
Late 1700s in Europe, late 1800s in the USA
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Energy consumption rose- burned more fossil
fuels

• Mechanization over came limiting factors
• created urban environments
• air pollution rose

Fossil fuels added CO2 to atmosphere,
magnifying the greenhouse effect
and increasing global warming
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Photochemical Smog

• A mix of pollutants formed under the influence of
  sunlight
• Forms in areas where there is a lot of sun and
  dry weather

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Large problem on the East coast where coal is a
major source of energy
Acid Rain
Formed when nitrogen oxides and sulfur dioxide
mix with the water in the atmosphere
Forms Sulfuric and Nitric acid
Enters biosphere as either dry fallout or rain
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What are the consequences for adding excess
energy into the biosphere?
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Greenhouse Gases

• CO2- 50 of warming,
• Water vapor-
• CH4 methane- 23xs more efficient than CO2,
• CFCs- 20,000xs more efficient than CO2,
  destroyed ozone layer

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Ozone Thinning
Chlorine and Bromine react in the stratosphere to
break apart the ozone O3 molecule to form oxygen
O2
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Myth buster
The thinning of the ozone layer and global
warming have nothing to do
with one another
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Threats from Global Warming

• Thermal expansion of the ocean-rise in sea level.
• Rapid shifts in Biomes- increased extinction
• Extreme climatic shifts
• Increase in human disease and pestilence
• Melting of the polar ice caps-
  snow reflects light, land absorbs it!

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As the climate in a region shifts species have
three choices

• Adapt
• Migrate
• go extinct

We are in the midst of the sixth mass extinction,
Why?
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Green Revolution
1950s
Monoculture big
business farming, more susceptible to pests
Increased use of fertilizers and pesticides
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Biomagnification
Substance is stored in fat transferred up the
food chain, each trophic level has
progressively higher concentration levels
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The levels of DDT were so high in the tertiary
consumers the egg shells would not harden
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How do we proceed in the future?
Sustainable Use
Focus on renewable resources solar, wind,
hydrogen
Live within our limiting factors