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First Law of Thermodynamics energy is neither created nor destroyed, but may be converted from one form to another. Second Law of Thermodynamics when energy is changed from one form to another, some useful energy is always degraded into lower quality energy (usually heat). Ionizing radiation radiation w/enough energy to free electrons from atoms forming ions, may cause cancer (ex. gamma, X-rays, UV). High Quality Energy organized & concentrated, can perform useful work (ex. fossil fuels & nuclear). Low Quality Energy disorganized, dispersed (ex. heat in ocean or air/wind, solar). Natural radioactive decay unstable radioisotopes decay releasing gamma rays, alpha & beta particles (ex. Radon). Half-life the time it takes for 1⁄2 of the mass of a radioisotope to decay. Estimate of how long a radioactive isotope must be stored until it decays to a safe level approximately 10 half-lives. Nuclear Fission nuclei of isotopes split apart when struck by neutrons. (Current nuclear energy) Nuclear Fusion 2 isotopes of light elements (H) forced together at high temperatures till they fuse to form a heavier nucleus. Happens in the Sun, very difficult to accomplish on Earth, prohibitively expensive. Ore a rock that contains a large enough concentration of a mineral making it profitable to mine. Organic fertilizer slow acting and long lasting because the organic remains need time to be decomposed. Best solution to energy shortage conservation and increased efficiency Mineral Reserve identified deposits currently profitable to extract. Surface mining cheaper, can remove more minerals, less hazardous to workers. Humus organic, dark material remaining after decomposition by microorganisms. Leaching removal of dissolved materials from soil by water moving downwards through soil. Loam perfect agricultural soil with equal portions of sand, silt, and clay. Conservation allows the use of resources in a responsible manner Preservation setting aside areas and protecting them from human activities Restoration to bring back to former condition, active restoration seeks to reestablish a diverse, dynamic community at a site that has been degraded Remediation Most often used with cleanup of chemical contaminants in a polluted area Mitigation Repairing/rehabilitating a damaged ecosystem or compensation for damage, most often by providing a substitute replacement area; frequently involves wetland ecosystems. Reclamation typically used to describe chemical or physical manipulations carried out in severely degraded sites, such as open-pit mines or large-scale construction Soil Conservation Methods conservation tillage, crop rotation, contour plowing, organic fertilizers. (know WHY) Hydrologic Cycle Components evaporation, transpiration, runoff, condensation, precipitation, and infiltration. Aquifer any water-bearing layer in the ground. Cone of Depression lowering of the water table around a pumping well. Salt Water Intrusion near the coast, overpumping of groundwater causes saltwater to move into the aquifer. ENSO El Nino Southern Oscillation, see-sawing of air pressure and trade winds over the South Pacific During an El Nino year Trade winds weaken & warm water sloshes towards SA During a La Nina "normal" year Easterly trade winds and ocean currents pool warm water in the western Pacific, allowing upwelling of nutrient rich water off the West coast of South America. Effects of El Nino upwelling decreases disrupting food chains and diminished fisheries off South America, drought in western Pacific, increased precipitation in southwestern North America, fewer Atlantic hurricanes. Nitrogen Fixation because atmospheric N cannot be used directly by plants, it must first be converted into ammonia by bacteria. Ammonification decomposers covert organic waste into ammonia. Nitrification ammonia is converted to nitrate ions (NO3-). Assimilation inorganic N is converted into organic molecules such as DNA/amino acids & proteins. Denitrification bacteria convert ammonia back into N. Phosphorus does not exist as a gas; released by weathering of phosphate rocks, it is a major limiting factor for plant growth. Phosphorus cycle is slow, and not atmospheric. Phosphorus does not circulate as easily as N because it does not exist as a gas, but is released by the weathering of phosphate rocks. Excess phosphorus is added to aquatic ecosystems by runoff of animal wastes, fertilizer, discharge of sewage. Sustainability the ability to meet humanities current needs without compromising the ability of future generations to meet their needs Photosynthesis plants convert CO2 (atmospheric C) into complex carbohydrates (glucose C6H12O6). Aerobic Respiration oxygen consuming producers, consumers & decomposers break down complex organic compounds & convert C back into CO2. Largest reservoirs of Carbon (carbon sinks) (1) carbonate rocks (2) oceans Net Primary Productivity amount of carbon from the atmosphere that gets added to green plants per unit time, rate at which new vegetation is added, calculated by total gain of plant biomass minus the losses due to plant respiration, this net gain is available to all other organisms as food, when NPP is high the higher the overall biomass and diversity Biotic/Abiotic living/nonliving components of an ecosystem. Producer/Autotroph organisms that make their own food—photosynthetic life. (Plants and some algae and bacteria) Fecal coliform bacteria indicator of sewage contamination in the water Trophic Levels producers primary consumer secondary consumer tertiary consumer. Energy Flow through Food Webs 10% of the usable energy is transferred to the next trophic level. Reason: usable energy lost as heat (2nd law), not all biomass is digested & absorbed, predators expend energy to catch prey. Chlorine good for disinfection of water Cogeneration using waste heat to make electricity Primary succession development of communities in a lifeless area not previously inhabited by life (ex. lava). Secondary succession life progresses where soil remains (ex. clear-cut forest, old farm). Mutualism symbiotic relationship where both organisms benefit. Commensalism symbiotic relationship where one organism benefits & the other is unaffected. Parasitism relationship in which one organism (the parasite) obtains nutrients at the expense of the host. Carrying Capacity the number of individuals that can be sustained in an area. r-strategist reproductive strategy in which organisms reproduce early, bear many small, unprotected offspring (ex. insects, mice). K-strategist reproductive strategy in which organisms reproduce late, bear few, cared for offspring (ex. humans, elephants). Natural Selection organisms that possess favorable adaptations pass them onto the next generation. Thomas Malthus "human population cannot continue to increase. Consequences will be war, famine & disease. Doubling Time (rule of 70) doubling time equals 70 divided by percent growth rate. (ex. a population growing at 5% annually doubles in 70 ÷ 5 = 14 years) Replacement Level Fertility the number of children a couple must have to replace themselves (2.1 more developed, 2.7 less). World Population 7 billion US Population 300 million Demographic Transition Model the stages a country must pass through when transitioning from developing to developed countries, triggered by economic development. Preindustrial stage birth & death rates high, population grows slowly, infant mortality high. Transitional stage triggered by death rate (infant mortality) lower, birth rates remain high, better health care, population grows fast. Industrial stage decline in birth rate, population growth slows. Postindustrial stage low birth & death rates. Age Structure Diagrams broad base =rapid growth; narrow base negative growth; uniform shape zero growth Most Populous Nations (1) China (2) India (3) U.S. Most important thing affecting population growth low status of women Methods to Decrease Birth Rates family planning, contraception, economic rewards & penalties - know examples, why, and how. Composition of Water on Earth 97.5% seawater, 2.5% freshwater. Soil Salinization in arid regions, water evaporates leaving salts behind. (ex. Fertile crescent, southwestern US) Ways to conserve water agriculture - drip irrigation, industry - recycling, conservation, home - conservation, use gray water, repair leaks, use low flow fixtures Biome large distinct terrestrial region having similar climate, soil, plants and animals Positive feedback when a change in some condition triggers a response that intensifies the changing condition (ex: warmer earth, snow melts, less sunlight reflected off the ice, makes earth even warmer) Negative feedback when a change in some condition triggers a response that counteracts the changed condition (ex: warmer earth, more ocean evaporation, more clouds, less sunlight reaches the ground - cooler earth) Point Source from specific location such as pipe or smokestack Non-Point Source from over an area such as agricultural (farm) runoff, traffic. BOD Biological Oxygen Demand, amount of dissolved oxygen needed by aerobic decomposers to break down organic materials. Eutrophication rapid algal growth caused by an excess of nitrogen & phosphorus. Hypoxia when aquatic plants die, the BOD rises as aerobic decomposers break down the plants, the DO drops & the water cannot support life Primary Air Pollutants produced by humans & nature (CO, CO2, SO2, NO, hydrocarbons, particulates). Secondary Air Pollutants formed by reaction of primary pollutants. (ozone, smog, acid rain) Particulate Matter (sources, effects, reduction) sources include burning fossil fuels and car exhaust. Effects include reduced visibility, respiratory irritation. Methods of reduction include filtering, electrostatic precipitators, alternative energy). Nitrogen Oxides (NOx) Major source is auto exhaust. Primary and secondary effects include acidification of lakes, respiratory irritation, leads to smog and ozone. Reduced using catalytic converters. Equation for acid formation NO + O2 NO2 + H2O HNO3. Ozone Secondary pollutant, NO2 + UV NO + O; O + O2 O3, with VOCs. Causes respiratory irritation and plant damage. Reduced by reducing NO emissions and VOCs. Sulfur Oxides (SOx) Primary source is coal burning. Primary and secondary effects include acid deposition, respiratory irritation, plant damage. Reduction methods include: scrubbers, burn low sulfur fuel. Equation for acid formation SO2 + O2 SO3 + H2O =H2SO4 Carbon Oxides (CO2 and CO) Sources include burning fossil fuels, incomplete combustion. Effects: CO binds to hemoglobin reducing bloods ability to carry O; CO2 contributes to global warming. Reduction accomplished by catalytic converters, emissions testing, oxygenated fuel, mass transit (reduction), raise CAFÉ standards. Industrial Smog found in cities that burn large amounts of coal Photochemical Smog formed by chemical reactions involving sunlight (NO, VOC, O) Acid Deposition caused by sulfuric and nitric acids resulting in lowered pH of surface waters Greenhouse Gases Most significant: H2O, CO2, O3, methane (CH4), CFCs. Trap outgoing infrared energy (heat) causing earth to warm. Greenhouse Effect a vital process, required for life to exist on Earth. If accelerated, bad, leads to global warming. Effects of Global Warming rising sea level (due to thermal expansion not melting ice), extreme weather, droughts ((famine), and extinctions. Ozone Depletion caused by CFCs, methyl chloroform, carbon tetrachloride, halon, methyl bromide all of which attack stratospheric ozone. Effects of Ozone Depletion increased UV, skin cancer, cataracts, and decreased plant growth. Radon radioactive gas, formed from the decay of Uranium in the earth's crust, gets into houses through cracks in foundation, causes lung cancer Municipal Solid Waste is mostly paper and mostly put into landfills. Sanitary Landfill problems include leachate, which is solved using a liner with a collection system; methane gas, which may be collected and burned and the volume of garbage, which may be compacted and/or reduced. Incineration Advantages-volume of waste reduced by 90% and waste heat can be used. Disadvantages-toxic emissions (polyvinyl chloride, dioxin), scrubbers and electrostatic precipitators needed, ash disposal (contains heavy metals). Best Solution for Waste Problem reduce the amount of waste at the source. Keystone Species species whose role in an ecosystem is more important than others. Ex. Sea Otter Indicator Species species that serve as early warnings that an ecosystem is being damaged. Ex. Trout, Reptiles, Birds Most Endangered Species have a small range, require large territory or live on an island. In Natural Ecosystems 50-90% of pest species are kept under control by: predators, diseases, parasites. Major Insecticide Groups chlorinated hydrocarbons—ex. DDT; organophosphates—ex. malathion; carbamates—ex. aldicarb Pesticide Pros saves lives from insect transmitted disease, increases food supply, and increases profits for farmers. Pesticide Cons genetic resistance, ecosystem imbalance, pesticide treadmill, persistence, bioaccumulation, and biological magnification. Natural Pest Control better agricultural practices, genetically resistant plants, natural enemies, and biopesticides, sex attractants. Electricity Generation steam, from water boiled by fossils fuels or nuclear energy, or falling water is used to turn a generator. Petroleum Formation microscopic aquatic organisms in sediments converted by heat & pressure into a mixture of hydrocarbons. Petroleum Pros cheap, easily transported, high-quality energy. Petroleum Cons reserves depleted soon, pollution during drilling, transport and refining, burning makes CO2. Coal Formation peat, lignite, bituminous coal, anthracite coal. Nuclear Reactor consists of a core, control rods, moderator, steam generator, turbine, containment building. Alternative Energy Sources wind, solar, waves, biomass, geothermal, fuel cells True cost/external costs harmful environmental side effects that are not reflected in the product's price LD-50 the amount of a chemical that kills 50% of the animals in a test population Mutagen causes hereditary changes. Teratogen causes fetus deformities. Carcinogen causes cancer. Multiple Use Public Lands National Forest & National Resource lands Moderately Restricted Use Public Lands National Wildlife Refuges Restricted Use Public Lands National Parks, National Wilderness Preservation System Volcanoes and Earthquakes Occur at tectonic plate boundaries: divergent—spreading (ex. mid-ocean ridges); convergent (ex.trenches); transform fault,—sliding (ex. San Andreas). Mineral Deposits most abundant at convergent plate boundaries. Garret Hardin & Tragedy of the Commons Global commons such as atmosphere and oceans are used by all and owned by none leading to rapid depletion.