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).
radiation w/enough energy to free electrons from atoms forming ions, may cause cancer (ex. gamma, X-rays, UV).
Natural radioactive decay
unstable radioisotopes decay releasing gamma rays, alpha & beta particles (ex. Radon).
Estimate of how long a radioactive isotope must be stored until it decays to a safe level
approximately 10 half-lives.
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.
slow acting and long lasting because the organic remains need time to be decomposed.
to bring back to former condition, active restoration seeks to reestablish a diverse, dynamic community at a site that has been degraded
Repairing/rehabilitating a damaged ecosystem or compensation for damage, most often by providing a substitute replacement area; frequently involves wetland ecosystems.
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.
Salt Water Intrusion
near the coast, overpumping of groundwater causes saltwater to move into the aquifer.
El Nino Southern Oscillation, see-sawing of air pressure and trade winds over the South Pacific
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.
because atmospheric N cannot be used directly by plants, it must first be converted into ammonia by bacteria.
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.
the ability to meet humanities current needs without compromising the ability of future generations to meet their needs
oxygen consuming producers, consumers & decomposers break down complex organic compounds & convert C back into CO2.
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
organisms that make their own food—photosynthetic life. (Plants and some algae and bacteria)
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.
development of communities in a lifeless area not previously inhabited by life (ex. lava).
relationship in which one organism (the parasite) obtains nutrients at the expense of the host.
reproductive strategy in which organisms reproduce early, bear many small, unprotected offspring (ex. insects, mice).
reproductive strategy in which organisms reproduce late, bear few, cared for offspring (ex. humans, elephants).
"human population cannot continue to increase. Consequences will be war, famine & disease.
(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).
Demographic Transition Model
the stages a country must pass through when transitioning from developing to developed countries, triggered by economic development.
triggered by death rate (infant mortality) lower, birth rates remain high, better health care, population grows fast.
Age Structure Diagrams
broad base =rapid growth; narrow base negative growth; uniform shape zero growth
Methods to Decrease Birth Rates
family planning, contraception, economic rewards & penalties - know examples, why, and how.
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
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)
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)
Biological Oxygen Demand, amount of dissolved oxygen needed by aerobic decomposers to break down organic materials.
when aquatic plants die, the BOD rises as aerobic decomposers break down the plants, the DO drops & the water cannot support life
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).
(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.
Secondary pollutant, NO2 + UV NO + O; O + O2 O3, with VOCs. Causes respiratory irritation and plant damage. Reduced by reducing NO emissions and VOCs.
(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.
(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.
Most significant: H2O, CO2, O3, methane (CH4), CFCs. Trap outgoing infrared energy (heat) causing earth to warm.
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.
caused by CFCs, methyl chloroform, carbon tetrachloride, halon, methyl bromide all of which attack stratospheric ozone.
radioactive gas, formed from the decay of Uranium in the earth's crust, gets into houses through cracks in foundation, causes lung cancer
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.
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).
species that serve as early warnings that an ecosystem is being damaged. Ex. Trout, Reptiles, Birds
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
saves lives from insect transmitted disease, increases food supply, and increases profits for farmers.
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.
steam, from water boiled by fossils fuels or nuclear energy, or falling water is used to turn a generator.
microscopic aquatic organisms in sediments converted by heat & pressure into a mixture of hydrocarbons.
reserves depleted soon, pollution during drilling, transport and refining, burning makes CO2.
consists of a core, control rods, moderator, steam generator, turbine, containment building.
True cost/external costs
harmful environmental side effects that are not reflected in the product's price
Volcanoes and Earthquakes
Occur at tectonic plate boundaries: divergent—spreading (ex. mid-ocean ridges); convergent (ex.trenches); transform fault,—sliding (ex. San Andreas).