Transcript Humans in the Biosphere

Human Impact on the Biosphere
Those Pesky Humans!
• Humans have a large impact on the
environment and the organisms we share
it with.
• This is due to our
– Ever increasing population size.
– Ever increasing use of both renewable and
non-renewable resources.
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
Global Climate Change
• Human activities have increased the
concentration of carbon, sulfur, and
nitrogen compounds in the atmosphere.
• The increase in these compounds has
resulted in changes in the natural climate
and weather patterns.
Remember the Carbon Cycle?
http://www.windows.ucar.edu/earth/climate/images/carboncycle.jpg
The Carbon Cycle
• Carbon cycles 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.
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 the ever increasing rate at which we:
– Clear-cut and burn forests for housing and farming
– Burn fossil fuels
• These activities have resulted in the phenomenon
of global warming.
Global Warming
• The greenhouse effect :
–
–
–
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The sun’s light hits the earth as UV light.
It is reflected back to space as IR light.
UV light can get through the atmosphere.
IR light gets trapped by greenhouse gases such as
CO2 and CH4.
– This traps the heat energy around the planet,
warming the Earth.
• Increase in greenhouse gases (CO2 and CH4)
= warmer temperatures
*******This is Global Warming********
http://www.darlington.gov.uk/NR/rdonlyres/2091F156-0B6A-456B-B5FA-24579F372F36/0/greenhouseeffect.jpg
Possible Affects of Global Warming
These include:
•Flooding of coastal areas.
•Increased spreading of disease.
•Drought across inland areas.
http://www.greatdreams.com/flood/flood-antigo-2004b.jpg
http://www.nytimes.com/2007/07/04/us/04drought.html?_r=1&oref=slogin
http://www.michigan.gov/images/mosquito_65147_7.jpg
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.
http://www.greeneducation.org.hk/English/focus/wpe28.gif
Effects of Acid Rain
http://www.newsroom.ucr.edu/releases/images/257_3.gif
http://www.scienceacross.org/media/acidrainstatueed.jpg
The Ozone Layer
• The ozone layer protects
us from UV light.
• UV light causes cancer,
eye damage, and can
damage plant tissue.
http://images.google.com/imgres?imgurl=http://www.ec.gc.ca/ozone/DOCS/KIDZONE/images/ozn_layr.gif&imgrefurl=http://www.ec.gc.ca/ozone/DOCS/KIDZONE/EN/ozoneupthere.cfm&h=4
25&w=301&sz=78&hl=en&start=3&tbnid=NLHDAmXoPwZ2M:&tbnh=126&tbnw=89&prev=/images%3Fq%3Dozone%2Blayer%26gbv%3D2%26svnum%3D10%26hl%3Den%26safe%3Dactive
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
What Destroys the Ozone Layer?
• Chlorofluorocarbons (CFC’s) are broken apart
by UV light. This causes a chain of chemical
reactions that results in ozone being broken
apart.
• CFC’s 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 CFC’s it will take
another 50 years before the hole in the ozone
layer begins to shrink and disappear.
Biological Magnification/
Bioaccumulation
• Biological
magnification/
Bioaccumulation
occurs when
pesticides build up in
animal tissue as you
move up a food chain.
Biological Magnification
• http://techalive.mtu.edu/meec/module02/Bi
oconcentrationandBioaccumulation.htm
DDT in Borneo
• 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…..
Parachuting Cats
http://imagecache2.allposters.com/images/pic/ARG/21033~Parachute-Cats-Posters.jpg
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.
• DDT is still in the
environment
despite the fact
that the last time
it was sprayed
was over 20
years ago.
Threatening Biodiversity
There are 4 basic ways that human actions
threaten biodiversity:
• Introducing non-native species
• Hunting organisms to extinction
• Introducing toxins into the environment
• Habitat destruction
Biodiversity is important
because…….
Many medicines come from nature
• We get digitalis,
a heart
medication, from
foxglove.
• Taxol is a chemical
extracted from the
Pacific Yew tree
• It is used for treating
cancer patients.
Imagine the possible undiscovered
medical miracles that could be
hiding in the areas/species that
have not been studied yet.
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.
Ecosystems are more stable
Ecosystems with more
organisms are more
stable (or homeostatic).
What can you do to help?
Are your actions sustainable?
References
http://www.environmentaldefense.org/images/issue_photo_12.jpg
http://www.ghgonline.org/images/fire.jpg
http://www.crh.noaa.gov/iwx/wxpics/flooding/woodburnaug01.jpeg
http://dep.state.ct.us/burnatr/wildlife/kids/images/kpmsqui2.gif
http://www.epa.gov/sunwise/images/ozone.gif
http://images.encarta.msn.com/xrefmedia/sharemed/targets/images/pho
/000f1/000f1c7d.jpg
http://www.anselm.edu/homepage/jpitocch/genbios/54-25DDTInFoodChain-L.jpg
http://www.americanroyalarts.com/library/FC12.jpg
http://www.fws.gov/endangered/photos/bird/baldeagle_in_snow.jpg
References
http://www.botgard.ucla.edu/html/botanytextbooks/economicbo
tany/images/Digitalis/Digitalisflowers.jpg
http://www.agen.ufl.edu/~chyn/age2062/lect/lect_28/40_07.GIF
http://www.answers.com/main/content/wp/encommons/b/bc/Rainforest_Fatu_Hiva.jpg
http://oceanworld.tamu.edu/students/coral/images/coral_reef_1.jpg
http://www.geo.msu.edu/geo333/images/slide1-R-corn.JPEG