Human Impact on the Biosphere

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Human Impact on the Biosphere
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Why do humans impact the environment?

• Humans have a large impact on the environment and
  the organisms we share it with.
• This is due to our
• Increasing population size.
• Increasing use of both renewable and
  non-renewable resources.

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The Carbon Cycle

• Cycling of carbon through the environment mainly
  in the form of CO2 and carbohydrates.
• Photosynthesis is the main process that removes
  carbon from the atmosphere.
• Cellular respiration is the main process that
  releases carbon into the atmosphere.

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What processes remove carbon dioxide from the
atmosphere?

• Photosynthesis by land and aquatic autotrophs
• Precipitation onto land ocean

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What processes release carbon dioxide into the
atmosphere?

• Cellular respiration by autotrophs
  heterotrophs.
• Decomposition of organisms
• Volcanic activity
• Human activities - mining, cutting and burning
  forests, and burning fossil fuels

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What stores carbon dioxide?

• Limestone (calcium carbonate) rock
• Decomposition of organisms and their conversion
  into fossil fuels
• Diffusion of carbon into the ocean

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The Carbon Cycle
http//www.windows.ucar.edu/earth/climate/images/c
arboncycle.jpg
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Human Activity and the Carbon Cycle

• Human activity is releasing CO2 and other related
  forms of carbon into the atmosphere at a much
  faster rate then they are absorbed.
• This is due to
• Clear-cutting and burning forests for housing and
  farming
• Burning fossil fuels
• These activities have resulted in a global
  climate change .

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What is the Greenhouse Effect?

• The greenhouse effect is the rise in temperature
  due to certain gases in the atmosphere (water
  vapor, carbon dioxide, methane (CH4) in
  particular) trapping out-going heat energy.
• Without these gases, heat would escape back into
  space and Earths average temperature would be
  about 60ºF colder.
• Because of how they warm our world, these gases
  are referred to as greenhouse gases.

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So then what is Global Warming?

• The Greenhouse Effect and Global Warming are NOT
  the same thing!!!
• Global Warming is the increase in the average
  measured temperature of the Earth's near-surface
  air and oceans.
• Global Warming affects the Greenhouse Effect.
• Greenhouse Effect GOOD
• Global Warming BAD

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What are the Possible Effects of Global Warming?

• These include
• Flooding of coastal areas.
• Increased spreading of disease.
• Drought across inland areas.

http//www.greatdreams.com/flood/flood-antigo-2004
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http//www.nytimes.com/2007/07/04/us/04drought.htm
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How are humans creating acid rain?

• The burning of fossil fuels also releases
  nitrogen and sulfur compounds into the
  atmosphere.
• These compounds combine with water vapor in the
  air to produce acids.
• The acids then migrate for miles and fall as acid
  rain.

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http//www.greeneducation.org.hk/English/focus/wpe
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Effects of Acid Rain

• Causes acidification of lakes and streams which
  affects aquatic ecosystems.
• Contributes to the damage of trees/plants by
  acidification of soils.
• In addition, acid rain accelerates the breakdown
  of building materials, paints, statues, and
  sculptures that are part of our cultural
  heritage.

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The Ozone Layer

• The ozone layer (O3), found in the stratosphere,
  protects us from UV light.
• UV light causes cancer, eye damage, and can
  damage plant tissue.

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The hole in the ozone layer South Pole
There is currently a large hole in the ozone
layer over Antartica.
http//www.solstation.com/stars/ozo-hole.jpg
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What Destroys the Ozone Layer?

• Chlorofluorocarbons (CFCs) are broken apart by
  UV light. This causes a chain of chemical
  reactions that results in ozone being broken
  apart.
• CFCs were used in aerosol cans, and as coolants
  in freezers and air conditioners. They are now
  banned, but some are still used in less developed
  areas.
• Even with decreased use of CFCs it will take
  another 50 years before the hole in the ozone
  layer begins to shrink and disappear.

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Biological Bioaccumulation/Magnification

• Biological Bioaccumulation (magnification)
  occurs when pesticides build up in animal tissue
  as you move up a food chain.

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Biological Accumulation

• http//techalive.mtu.edu/meec/module02/Bioconcentr
  ationandBioaccumulation.htm

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What are some examples of how humans assist in
bioaccumulation?

• DDT was used in Borneo to kill mosquitoes.
  Lizards ate the mosquitoes. Cats ate the
  lizards. Cats began dying.
• With no cats, the rat population grew.
• Rats began spreading disease.
• They came up with an interesting solution..

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Parachuting Cats
http//imagecache2.allposters.com/images/pic/ARG/2
1033Parachute-Cats-Posters.jpg
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DDT in the United States

• DDT was used to kill mosquitoes.
• DDT bioaccumulated and was found in high levels
  in the bald eagle.
• DDT caused the birds to lay eggs with pores in
  their shells.
• When the parent birds sat on the eggs, the eggs
  broke.
• Our national bird almost went extinct.

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• DDT is still in the environment despite the fact
  that the last time it was sprayed was over 20
  years ago.

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How do humans threaten biodiversity?

• There are 4 basic ways that human actions
  threaten biodiversity
• Introducing non-native species (invasive species)
• Hunting organisms to extinction
• Introducing toxins into the environment
• Habitat destruction

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Invasive species in NC

• Plants and animals brought into an area form
  other places can become invasive species.
  Invasive species can multiply quickly if there
  are no parasites or predators to control their
  numbers.For exampleKudzu was first
• introduced to the
• United States as an
• ornamental plant,
• but it quickly became an
• invasive species in much
• of the Southeastern U.S.

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Biodiversity is important because.
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Many medicines come from nature

• We get digitalis, a heart medication, from
  foxglove.
• We get Taxol, the cancer fighting chemical, from
  Pacific yew.

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Imagine the possible undiscovered medical
miracles that could be hiding in the
areas/species that have not been studied yet.
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We get genetic diversity

• Most crop plants have wild relatives with useful
  traits.
• We will visit this library when we need genes
  to improve our crop plants.

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Ecosystems are more stable

• Ecosystems with more
• organisms are more
• stable (or homeostatic).

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Summary

• Humans Affect the Biosphere in 4 Essential Ways
• A. Global Climate Change and Acid Rain
• B. The Ozone Layer
• C. Biological Magnification/Bioaccumulation
• D. Threatening Biodiversity

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What can you do to help?

• Are your actions sustainable?

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References
http//www.environmentaldefense.org/images/issue_p
hoto_12.jpg
http//www.ghgonline.org/images/fire.jpg
http//www.crh.noaa.gov/iwx/wxpics/flooding/woodbu
rnaug01.jpeg
http//dep.state.ct.us/burnatr/wildlife/kids/imag
es/kpmsqui2.gif
http//www.epa.gov/sunwise/images/ozone.gif
http//images.encarta.msn.com/xrefmedia/sharemed/t
argets/images/pho/000f1/000f1c7d.jpg
http//www.anselm.edu/homepage/jpitocch/genbios/54
-25-DDTInFoodChain-L.jpg
http//www.americanroyalarts.com/library/FC12.jpg
http//www.fws.gov/endangered/photos/bird/baldeagl
e_in_snow.jpg
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References
http//www.botgard.ucla.edu/html/botanytextbooks/e
conomicbotany/images/Digitalis/Digitalisflowers.jp
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http//www.agen.ufl.edu/chyn/age2062/lect/lect_28
/40_07.GIF
http//www.answers.com/main/content/wp/en-commons/
b/bc/Rainforest_Fatu_Hiva.jpg
http//oceanworld.tamu.edu/students/coral/images/c
oral_reef_1.jpg
http//www.geo.msu.edu/geo333/images/slide1-R-corn
.JPEG