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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