Mismanagement of Natural Resources: Soil Erosion, Desertification, Fishery & Freshwater, Slides of Biology

Download Mismanagement of Natural Resources: Soil Erosion, Desertification, Fishery & Freshwater and more Slides Biology in PDF only on Docsity! Humans in Biosphere Docsity.com The Tragedy of the Commons • Areas used by everyone are no one’s responsibility • Leads to misuse; loss of resources Docsity.com Nonrenewable Resources • Cannot be replenished by natural processes. • Examples: – Fossil fuels Docsity.com Is a tree population renewable or nonrenewable? • Individual trees are renewable • A population of trees may not be, because the ecosystem they were in may change forever once the trees are gone. Docsity.com Sustainable Development • Using resources without depleting them • Providing for human needs without causing long-term damage to the environment • Must take into account – Functioning of ecosystems – Human economic systems Docsity.com Mismanagement of Soil Resources • Soil Erosion – Wearing away of surface soil by water and wind – Results when land is plowed, and roots that hold soil in place are removed Docsity.com Mismanagement of Soil Resources • Desertification – Misuse of soil causes once productive areas to become deserts • Dry climate • Farming • Overgrazing • Drought Docsity.com To help protect your privacy, PowerPoint has blocked automatic download of this picture. Forest Resources • Ways in which forest resources are used by people – Building – Burning Docsity.com Old Growth Forest Docsity.com Deforestation • Definition: The loss of forests • Deforestation can lead to – Severe soil erosion – Erosion can wash nutrients out of the soil – Grazing or plowing after deforestation can cause permanent changes in the soils that prevent regrowth of trees. Docsity.com Fishery Resources • Overfishing – Harvesting fish at a rate greater than they can replace themselves by reproduction – 1950 – 1990 • Fish harvest dramatically increased • Fish populations dramatically declined • “Tragedy of the Commons” – Fishing of certain species banned • Some populations have seen recovery Docsity.com Aquaculture • Raising aquatic animals for human consumptions – Good: provides food for people without drawing from natural populations – Disposal of wastes from the aquatic animals can be a source of pollution Docsity.com Air Resources • Smog – Mixture of chemicals that results in a brown/gray haze in the atmosphere. • Mostly due to – Automobile exhaust – Industrial emissions Docsity.com Pollutant • A harmful material that can enter the biosphere through the land, air or water. • Pollutants released from burning fossil fuels include: – Carbon dioxide – Nitrates and Sulfates – Particulates Docsity.com Freshwater Resources • People use freshwater for – Drinking – Washing – Watering crops – Industry – Recreation Docsity.com Pollution Threatens Freshwater Supplies • Improperly discarded chemicals can enter streams and rivers • Wastes discarded on land can seep through soil into groundwater supplies • Sewage containing phosphorus and nitrogen encourages algae growth – Eutrophication – Leads to loss of oxygen when algae decay • Sewage can also spread disease – Though most cities due try to treat sewage before it enters water ways… – Still, animal waste runs off cow pastures, etc. Docsity.com Protection of Wetlands and the sustainable use of water • Wetlands act to purify water that passes through them • Saving wetlands means cleaner water Docsity.com Species Status • Threatened – A species that is likely to become endangered if it is not protected • Endangered – any species which is "in danger of extinction throughout all or a significant portion of its range." • Extinct – a species that no longer exists Docsity.com Extinction Rate Today • Are we undergoing a mass extinction? – Yes. – Normal extinction rate between 10 and 100 species per year • Remember – this includes all life – bacteria, protists, plants, etc. – Current extinction rate may be as high as 27,000 species per year – What is the cause? Docsity.com Why is biodiversity of practical value to humans? • Species of many kinds have provided us with foods, industrial products and medicines • Inherent value just of its own merit??? Docsity.com Habitat fragmentation Docsity.com Box Turtles and Habitat Fragmentation Docsity.com Demand for Wildlife Products • Demand for animal species products has caused extinction by hunting – Carolina parakeet – Passenger pigeon Docsity.com DDT concentration: increase of 10 million times zooplankton 0.04 ppm ‘Copyright @ Pearson Education, Inc., publishing as Benjamin Gummings. Docsity.com " Concentration any Famous Incidents of Biological Magnification • DDT Docsity.com Docsity.com Other pollutants and biological magnification • PCBs – Great Lakes – Endocrine system problems in lots of animals including humans – Concentration in Herring Gull eggs is 5,000 times greater than in phytoplankton at base of food web Docsity.com Other Pollutants and Biological Magnification • Mercury – By-product of plastic production – Plastic production and coal power plants – Expelled into rivers/oceans – Bacteria at the bottom mud convert to a more harmful substance • Methyl mercury • Accumulates in tissues of organisms including humans Docsity.com Zebra mussels • Native to freshwater lakes of southeast Russia • Spread began in 1700s • First discovered in this country in Great Lakes in 1988 • Ballast water from ships probably responsible for introduction Docsity.com Kudzu Docsity.com Kudzu • Introduced intentionally in 1876 as a forage crop and ornamental plant • From 1935 to 1950 farmers were encouraged to plant it to prevent erosion • The southern U.S. has near perfect conditions for this plant to grow out of control, which it has done. Docsity.com Northern Snakehead • Native to China, Russia, Korea • Top level predator • First reported in U.S. in 2000 in pond in Maryland • Found in pond in Chesapeake Bay watershed – pond was drained and the fish were destroyed • A man admitted releasing two snakeheads into the pond after purchasing them in NY • 19 found in Potomac River in 2004 • Found in other states now Docsity.com Phragmites • Highly invasive • Threatens native marsh plants Docsity.com Veined Rapa Whelk • Our Knobbed whelk at left • Rapa Whelk on right w/ egg masses on far right Docsity.com Conservation Strategies • Preventing single species extinction • Example – Zoos – Establish captive breeding programs – Raise and protect animals until population is stable – then return to wild. Docsity.com Conservation Strategies • Now more focused on protecting entire ecosystems – Ensures that natural habitats and interactions of many different species are preserved at the same time – Much bigger challenge • Governments and conservation groups must work together to set aside land, etc. • Even though the U.S. has lots of national parks, etc., this is not nearly enough to protect biodiversity Docsity.com Hot Spots • Places where large numbers of habitats and species are in immediate danger of extinction as a result of human activity • Hot spot strategy MAY help to focus efforts Docsity.com Ozone depletion • Ozone layer – 20 – 50 km above Earth’s surface – Made of O3 – A pollutant at Earth’s surface – Protects people from UV radiation Docsity.com Ozone depletion • Hole in ozone was discovered in 1970s – Image is from 2006 • Over Antarctica • Continued to grow larger and last longer • 1974 – Cause of ozone hole determined – Chlorofluorocarbons (CFCs) • Propellants in aerosol cans • Coolant in refrigerators, air conditioners, etc. Docsity.com Ozone depletion • 1987, US and many other nations began reducing use of CFCs • Today they are mostly banned • Effects of ban will not be seen right away – CFCs linger for years in the atmosphere – Ozone hole should shrink and disappear in 50 years Docsity.com Global Warming • Definition – increase of average temperature of the biosphere • Records show: – Since 1900 temp has risen .6 C – Since 1980 temp has risen .2 to .3 C – 1990s were warmest decade on record – 1998 was warmest year on record Docsity.com Is Global Warming REALLY occurring • YES Docsity.com Is global warming due to human activity? • Earth’s climate does fluctuate naturally – Remember, there was once an ice age – Glaciers have advanced and retreated over geologic history • Couldn’t the rise in temperatures we’re observing be part of this natural fluctuation? 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