Transcript Human Impact on 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 AND
ACID RAIN
Human Activity and the Carbon Cycle
• We are releasing CO2 and other related forms of carbon
into the atmosphere at a much faster rate than 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.
FACTS WE KNOW
Global temperatures have increased 0.5-1.0°F since the
late 19th century.
http://content.answers.com/main/content/wp/en/thumb/8/87/280px-Instrumental_Temperature_Record.png
FACTS WE KNOW
The snow cover in the Northern Hemisphere and floating
ice in the Arctic Ocean have decreased.
Graph & glacier pix: http://nsidc.org/sotc/glacier_balance.html
polar bears: http://www.metro.co.uk/news/article.html?in_article_id=35720&in_page_id=34
What’s so bad about warming up a little?
http://healthandenergy.com/images/global2.gif
Cartoon from Brookings Register
Coastal flooding
What’s so bad about warming up a little?
http://en.wikipedia.org/wiki/Hurricane_Katrina
http://i.a.cnn.net/cnn/2005/WEATHER/08/25/tropical.storm/story.katrina.915p.jpg
More severe storms
http://www.claybennett.com/pages/ocean_temps.html
What’s so bad about warming up a little?
Changes in
Gulf Stream
http://zfacts.com/metaPage/lib/Atlantic_conveyor.jpg
What’s so bad about warming up a little?
Weather
extremes
Heat waves and drought
Brookings Register
What’s so bad about warming up a little?
http://www.metro.co.uk/news/article.html?in_article_id=35720&in_page_id=34
Changing habitats
means
loss of species
Acid Rain
• The burning of fossil fuels also releases
nitrogen and sulfur compounds.
• These compounds combine with water vapor
in the air to produce acids.
• The acids then migrate for miles and fall as
acid rain.
Effects of Acid Rain
Effects of Acid Rain
THE OZONE LAYER
OZONE LAYER
• The ozone layer
protects us from UV
light.
• UV light causes
cancer, eye damage,
and can damage
plant tissue
http://pubweb.bnl.gov/users/xujun/www/bnl/ozone_layer_1.gif
WHAT WE KNOW
Scientists have been
depletion
monitoring the ____________
of ozone in our atmosphere
and have discovered
a hole in the ozone layer
Antarctica
over ____________.
http://ozonewatch.gsfc.nasa.gov/facts/hole.html
What’s the cause of Ozone
Depletion?
Chlorofluorocarbon
(CFC’s)
molecules _______
released from
air conditioners,
aerosol spray cans,
fire extinguishers,
and industry
destroy ozone
________________
http://www.atm.ch.cam.ac.uk/tour/part3.html
THAT’S WHY . . .
http://www.roundrocktexas.gov/images/spray_cans_large.jpg
AEROSOL
_____________spray
cans
no longer contain
CFC propellants.
AIR CONDITIONERS
Gases in ___________________
refrigerators are collected
and _____________
and recycled.
Pop Quiz
• Have out a sheet of Paper and number it 1-4.
• Read each question and write down only the
letter of your choice.
• Good Luck
1. Which of the following is
an example of ecological
succession?
• A. spring followed by
summer
• B. tadpole becoming a frog
• C. meadow replacing a field
• D. predators eating prey
2.What is the main suspected
environmental problem
associated with the
burning of fossil fuels?
•
•
•
•
A. depletion of fresh water
B. depletion of ozone
C. global cooling
D. global warming
3. Which of the following
is a side effect of acid
rain.
A. Large animals
B. Cancer
C. Damage to trees
D. Rusty cars
• The ozone layer
protects Earth by
absorbing –
• A. cosmic dust
• B. solar heat
• C. ultraviolet radiation
• D. white-light
frequencies
BIOACCUMULATION
Biological Magnification/
Bioaccumulation
• Biological
magnification/
Bioaccumulation occurs
when pesticides build
up in animal tissue as
you move up a food
chain.
Example:
_____
DDT was first modern insecticide
It was cheap, stayed active for long time, and
kills many different insects
Used to control agriculture pests
and disease carrying
MOSQUITOES
_______________
http://www.michigan.gov/images/mosquito_65147_7.jpg
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 causes birds to lay
fragile
eggs with ___________
shells so eggs would
break when sat on.
American Bald Eagle was declared
endangered in 1967. It has since been
“threatened”
reclassified as _____________________
THREATENING BIODIVERSITY
The sum of the genetically based
variety of all the organisms in the
BIODIVERSITY
biosphere = ___________________
stability to the
Biodiversity gives __________
ecosystems that we are so dependent
productivity and
on, enhances their ____________,
provides an important source of new
medicine and other _________
food
products
_____, ________,
.
Threatening Biodiversity
There are 3 basic ways that human actions
threaten biodiversity:
• Introducing non-native species
• Hunting organisms to extinction
• Habitat destruction
BIODIVERSITY THREAT
One of most important threats to
biodiversity come from apparently
harmless plants or animals that
humans transport into new habitats =
_____________________
INVASIVE SPECIES
PREDATORS
New habitats don’t have ____________
and parasites that control the population
in their native habitats, so invasive species
INCREASE rapidly.
populations _____________
EXAMPLES OF INVASIVE SPECIES
http://psephos.adam-carr.net/countries/a/australia/images/australiamap.gif
24 rabbits turned loose for
hunting in 1859 in Australia,
reproduced at such a rapid rate
they have taken over
the continent.
It is still a major problem and
rabbit diseases have been
purposely introduced to try to
control the population
http://en.wikipedia.org/wiki/Image:Wild_rabbit.jpg
Hunting Organisms to Extinction
Habitat Destruction
Development of natural areas for cities or
agriculture
http://www.simtropolis.com/idealbb/files/SG_ShoppingCenter.JPG
BIODIVERSITY THREAT
http://www.lubee.org/images/about-threats-1.jpg
Tropical rainforests are disappearing
at a rate of about 80 acres per minute.
http://www.abc.net.au/news/newsitems/200506/s1384632.htm
BIODIVERSITY THREAT
Changes in Brazilian rainforest over 30 years
The tropical rainforests once covered more than 14%
of the earth's total land surface,
but now cover less than 6%.
Can lead to species Extinction
Endangered Species
Worlds Rarest Animal
ONCE THOUGHT EXTINCT
WHAT CAN WE DO???
WHAT DOES IT MEAN?
REMEMBER!
Everything is connected.
BIODIVERSITY is a measure
of the health of an ecosystem.
Image from: Pearson Education Inc, publishing as Pearson Prentice Hall ©2006
CONSERVING BIODIVERSITY
Examples of efforts to keep a species from
becoming extinct:
Captive breeding
___________________
(raised and protected in zoos until population is
stable, then returned to wild
http://www.blackfootedferret.org/
Practice Questions
• A species that enters
an environment where
it has not lived before
is called an
• A. endangered
• B. invasive
• C. Threatened
• D. Predator
• A species whose
population is declining
so rapidly that it could
become extinct is
• A. non-native
• B. fragmented
• C. endangered
• D. Invasive
Ecology Study Guide
• Chapter 3 study guide questions
• Notes on Energy Flow
–Food webs
–Food Chains
–Energy Pyramids
–Biomass Pyramids
 Cycles
–Water
–Carbon
–Nitrogen
 Biological communities
Biomes
• Ecological Succession
– Primary vs secondary
• Population Ecology Notes
– Graphs, growth rate, factors that effect
population size
• Human and the Environment
– DDT, Acid Rain, Ozone layer, biodiversity, global
warming