Sylvia S. Mader - 醫學影像暨放射科學系暨碩士班

1 Essentials of BiologySylvia S. MaderChapter 32 Lecture OutlinePrepared by: Dr. Stephen EbbsSouthern Illinois University CarbondaleCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or Resources and Pollution Resourcesare the materials that meet the basic needs of living organisms. There is a finite supply of nonrenewable resources. Renewable resourcesare continually produced and are not finite. Pollutionoccurs when the release of by-products from resource utilization alter the environment in an undesirable Humans require land for habitation, industry, and agriculture. Human use of land has negative impacts. Human activities contribute to the erosionand pollution of beaches. The use of land located near deserts can lead to desertification. Deforestationof land can also lead to desertification and a loss of (cont.)

2 Land(cont.)Land(cont.)Water Humans alter the distribution of water in the environment with dams and aquifers. Dams have several negative impacts. The natural course of rivers is disrupted, damaging estuaries. Water is lost by evaporation and seepage. Salt and agricultural runoff can affect the water. Sediment can build up, reducing the effectiveness of the (cont.) Water redistribution and/or removal can have other consequences for the environment. Subsidencecan occur when groundwater is removed. Groundwater removal can also cause saltwater intrusion. Water conservationis becoming increasingly important as the availability of potable water supplies Modern agricultural techniques have had several negative effects. Monoculture has increased the susceptibility of crops to disease and insect herbivory.

3 Heavy use of fertilizers and pesticides has polluted the (cont.) Over-irrigation has depleted water supplies. Energy consumption during agriculture has drawn from finite fossil fuel supplies. Agriculture has contributed to soil loss. Food (cont.) Other efforts to enhance the human food supply have had mixed results. The Green Revolution and genetic engineering have produced high productivity plants that often require high inputs of water and (cont.) Livestock production has provided protein for the human diet but has also been energy intensive and a source of pollution. Fishing has also provided protein but is depleting the populations of some Nuclear power provides approximately 6% of the world s energy. Nuclear power can be dangerous and produces radioactive wastes that persist for thousands of years.

4 Most of the world s energy (approximately 75%) is provided by nonrenewable fossil fuels. The burning of these fossil fuels introduces pollutants into the Fuels and Global Climate Change Carbon dioxide, a by-product of fossil fuel production, is a greenhouse gas that many believe is causing global climate change. Temperatures are expected to rise. The polar ice caps will melt. The melting ice caps will cause sea levels to Fuels and Global Climate Change(cont.)Renewable Energy Sources There are five main forms of renewable energy. Windpower Hydropower(hydroelectric power) The geothermal energy(heat from beneath the Earth s surface) Solar energy Solar-hydrogen energy(extraction of hydrogen from water by electrolysis)Renewable Energy Sources(cont.)Minerals Mineralsare nonrenewable resourcesthat are often mined from the environment.

5 Fossil fuelsare considered minerals. Nonmetallic mineralsinclude phosphate, sand, and gravel. Examples of metallic mineralsinclude aluminum, copper, iron, nickel, and precious metals. Other Sources of Pollution Heavy metals are a threat to human health and ecosystem health. Synthetic organic compounds can be toxic and can influence global climate change. These toxic compounds can accumulate in food chains through biological Sources of Pollution (cont.)Other Sources of Pollution Industrial wastes pollute the environment by releasing potentially hazardous compounds. Release of raw sewage can contribute to human disease and pollute water sources. Biodiversity Biodiversitycan be described as the variety of life on the Earth. Currently, biodiversity is decreasing due to rapid extinction of species.

6 Extinctionis caused by a variety of factors. conservation biologyis an effort to protect Biodiversity (cont.)Direct Values of Biodiversity Biodiversity can provide value directly to humans. Medicinal value through pharmaceuticals and natural compounds Agricultural value as a food source Consumptive use value for commercial productsIndirect Values of Biodiversity Biodiversity can provide indirect value. Contribution to the biogeochemical cycling of nutrients in the environment Disposal of wastes (decomposition) Natural filtration and regeneration of water sources Reduction of erosion Regulation of climate EcotourismIndirect Values of Biodiversity (cont.)Working Toward a Sustainable Society A sustainable societycan provide the needed resources and protect biodiversity. Current human society is not sustainable.

7 More land is used for human purposes, rather than left as natural ecosystems. Agriculture relies on nonrenewable resources. Too much agriculture is devoted to livestock. There is too much reliance on nonrenewable fossil fuels and minerals. Working Toward a Sustainable Society (cont.)Working Toward a Sustainable Society (cont.) A sustainable society would have the following characteristics. Renewable energy sources would be used to provide energy. Heat and waste materials would be used efficiently. There would be maximal recycling of all Toward a Sustainable Society (cont.)