202 terms

Starr ES AP Test Terms Mega Review A-G

1977 Surface Mining Control and Reclamation Act
This Act establishes a program for regulating surface coal mining and reclamation activities. It establishes mandatory uniform standards for these activities on state and federal lands, including a requirement that adverse impacts on fish, wildlife and related environmental values be minimized. The Act creates an Abandoned Mine Reclamation Fund for use in reclaiming and restoring land and water resources adversely affected by coal mining practices.
1st Law of Thermodynamics (Energy)
The principle that energy may not be created or destroyed but is always conserved.
2nd Law of Thermodynamics (Energy)
A fundamental principle of energy that states that energy always tends to go from a more usable (higher equality) form to a less usable (lower quality) form. When we say that energy is converted to a less useful form we mean that entropy (a measure of the energy unavailable to do useful work) of the system has increased.
A Horizon
Horizon that is composed of both mineral and organic materials. The color is often light black to brown. Leaching, defined as the process of dissolving, washing, or draining earth materials by percolation of groundwater or other liquids, occurs in the A horizon and moves clay and other materials, such as iron and calcium, to the B horizon.
The nonliving components of an ecosystem.
The ability of matter to absorb light energy shined on it. This light energy is converted into heat.
The degree of conformity of an indicated value to an accepted standard value, or ideal value.
Acid Deposition
A comprehensive term for the various ways acidic compounds precipitate from the atmosphere and deposit onto surfaces. It can include: 1) wet deposition by means of acid rain, fog, and snow; and 2) dry deposition of acidic particles (aerosols).
Acid Mine Drainage
Does not refer to an acid mine but to acidic water that drains from mining areas (mostly coal but also metal mines). The acidic water may enter surface water resources, causing environmental damage.
Acid Rain
Rain made artificially by pollutants, particularly oxides of sulfur and nitrogen. (Natural rainwater is slightly acidic owing to the effect of carbon dioxide dissolved in the water.)
Active Solar Energy
Solar radiation used by special equipment to provide space heating, hot water or electricity.
Acute Effects (Exposure)
Effects usually immediate, obvious, short-term responses to exposure to a hazard; they can be localized to one part of the body or they can be systemic.
Living or occurring only in the presence of oxygen.
Aesthetic Justification (for the conservation of nature)
An argument for the conservation of nature on the grounds that nature is beautiful and that beauty is important and valuable to people.
African Black Rhinoceros
The African black rhinoceros is on the endangered species list due to excessive poaching for their horns, which are mostly used in dagger handles as a symbol of wealth in many countries.
Age Structure (of a population)
Structure of a population divided into groups by age. Sometimes the groups represent the actual number of each age in the population or proportion of the population of each age.
Age Structure Diagram
A representation of the number of individuals in each age group in a population.
Reflectivity; the fraction of radiation striking a surface that is reflected by that surface.
Very reactive organic compounds that contribute to local and regional ozone production, and also act as the precursors of peroxyacetyl nitrates. Their major atmospheric fate is reaction with hydroxyl radicals or photolysis.
Microscopic air sacs in the lungs at the end of bronchioles where gases are exchanged.
Living, active or occurring in the absence of oxygen. Without oxygen.
Anthracite Coal
A shiny black hard natural coal that burns slowly and gives intense heat, and the most efficient coal in the deepest parts of the Earth.
Produced by human activity.
Production of food from aquatic habitats.
A constructed system of canals, channels and/or pipelines to move water from one location to another.
Area (Non
point) Source- A source of pollution that cannot always be traced to an exact point of entry.
Artesian Well
A well in which the water comes from a confined aquifer and is under pressure.
Aswan High Dam
One of the world's largest dams on the Nile River in southern Egypt.
The layer of gases surrounding Earth.
An organism that produces its own food from inorganic compounds and a source of energy. There are photoautotrophs (photosynthetic plants) and chemical autotrophs.
An organism that produces its own food from inorganic compounds and a source of energy. There are photoautotrophs (photosynthetic plants) and chemical autotrophs.
B Horizon
Horizon that is enriched in clay, iron oxides, silica, carbonate or other material leached from overlying horizons. This horizon is known as the zone of accumulation.
Baby Boom
The jump in birthrates in the years after World War Two. "Baby boomers" are the generation born between 1945 and about 1960. In this period, more than 65 million children were born. They grew up in a generally prosperous period in American life, but also experienced as teenagers the uncertainties and conflicts of the 1950s and 1960s.
Background Extinction
The continuous, low-level extinction of species that has occurred throughout much of history.
Background Radiation
Radiation that comes from natural sources and is always present in the environment. This includes solar and cosmic radiation as well as radioactive elements in the ground, building materials, and the human body. Average annual dose of background radiation for an American is about 360 milligrams.
Baghouse Filter
Large fabric bag, usually made of glass fibers, used to eliminate intermediate and large (greater than 20 PM in diameter) particles. This device operates like the bag of an electric vacuum cleaner, passing the air and smaller particles while entrapping the larger ones.
The raw material mined from the earth we use to make aluminum.
The bottom of a sea or lake.
A process by which chemical substances are ingested and retained by organisms, either from the environment directly or through consumption of food containing the substances.
An environmentally safe, low polluting fuel for most diesel internal combustion and turbine engines. Can be mixed with petroleum diesel fuel and stored anywhere petroleum is. Made from fresh or waste vegetable oils (triglycerides) that are a renewable energy source. Both commercially and privately made around the world.
The number and variety of living organisms; includes genetic diversity, species diversity, and ecological diversity.
The large-scale geographic pattern in the distribution of species, and the causes and history of this distribution.
Biological Control
A set of methods to control pest organisms by using natural ecological interactions, including predation, parasitism, and competition. Part of the integrated pest management (IPM).
Biological Evolution
The change in inherited characteristics of a population from generation to generation, which can result in new species.
Also called biological concentration. The tendency for some substances to concentrate with each trophic level. Organisms preferentially store certain chemicals and excrete others. When this occurs consistently among organisms, the stored chemicals increase as a percentage of the body weights as the material is transferred along a food chain or trophic level. Fore example, the concentration of DDT is greater in herbivores than in plants and greater in plants in the nonliving environment.
The amount of living material or the amount of organic material contained in living organisms, both as live and dead material, as in the leaves (live) and stem wood (dead) of trees.
Biomass Energy
A new name for the oldest fuel used by humans, that is also called Biomass Fuel. Biomass Energy is organic matter, such as plant material and animal waste, which can be used as a fuel.
A kind of ecosystem. The rain forest is an example of a biome; rain forests occur in many parts of the world but are not all connected with each other.
A method of treating groundwater pollution problems that utilizes microorganisms in the ground to consume or break down pollutants.
A method of treating groundwater pollution problems that utilizes microorganisms in the ground to consume or break down pollutants.
A general term for all the organism of all species living in an area or region up to and including the biosphere, as in "the biota of the Mojave Desert" or "the biota in that aquarium."
The living components of an ecosystem.
Birth Rate
The rate at which births occur in a population, measured either as the number of individuals born per unit of time compared with the population.
Bituminous Coal
A dense, black, soft coal, often with well-defined bands of bright and dull material. The most common coal, with moisture content usually less than 20 percent. Used for generating electricity, making coke, and space heating.
Board Feet
The most common measure used to describe log and lumber volume. A board foot is a board measuring 12 x 12 x 1 thick.
BOD (Biological Oxygen Demand)
A measure of the amount of oxygen necessary to decompose organic material in a unit volume of water. As the amount of organic waste in water increases, more oxygen is used, resulting in a higher BOD.
Body Burden
The amount of concentration of a toxic chemical, especially radionuclides, in an individual.
A bog is a wetland type that accumulates acidic peat, a deposit of dead plant material.
Breeder Reactor
A nuclear reactor that manufactures more fissionable isotopes than it consumes. Breeder reactors use the widely available, nonfissionable uranium isotope U-238, together with small amounts of fissionable U-235, to produce a fissionable isotope of plutonium, Pu-239.
British Thermal Unit (BTU)
A unit used to measure quantity of heat, defined as the quantity of energy necessary to raise the temperature of 1 lb. of water 1° Fahrenheit.
Broad Spectrum Pesticide
Pesticides that kill a wide variety of organisms. Arsenic, one of the first elements used as a pesticide, is toxic to many life-forms, including people.
Small airway (subdivision of the bronchus) that leads to areas of the lung and absorbs oxygen from the air.
An abandoned or underutilized property that is not being redeveloped because of fears that it may be contaminated with hazardous substances.
Materials (chemicals) that have the ability to neutralize acids. Examples include the calcium carbonate that is present in many soils and rocks. These materials may lessen potential adverse effects of acid rain.
C Horizon
Horizon is composed of partially altered (weathered) parent material; the material could be rock or be alluvial in nature, such as river gravels in other environments. This horizon may be stained red with iron oxides.
California Condor
A large, endangered North American bird with the largest wingspan in the western Hemisphere.
California Water Project
The California State Water Project (SWP) is one of the largest water development projects in US. The Project was designed to transfer 5.4 BCM from the northern Sacramento River basin to areas of need in central and Southern regions of the State. Also, it is the key means for the State to re-route water among critical regions in times of severe shortages.
Carbon Cycle
Combined biochemical cycles of carbon, oxygen, and hydrogen. Carbon combines with and is chemically and biologically linked with the cycles of oxygen and hydrogen that form the major compounds of life.
Any material that is known to produce cancer in humans or other animals.
Organisms that feed on other live organisms; usually applied to animals that eat other animals; a meat eater.
Carrying Capacity
The maximum abundance of a population or species that can be maintained by a habitat or ecosystem without degrading the ability of that habitat or ecosystem to maintain that abundance in the future.
Cash Crop
Crops grown to be traded in a market.
Catalytic Converter
An air pollution abatement device that removes pollutants from motor vehicle exhaust, either by oxidizing them into carbon dioxide and water or reducing them to nitrogen.
CERCLA (The Superfund Act)
An act that gave EPA the authority to clean up abandoned, leaky hazardous waste sites.
Chain Reaction
A self-sustaining series of reactions, in particular those of nuclear fission in which the particles released by one nucleus trigger the fission of at least as many further nuclei.
An engineering technique that consists of straightening, deepening, widening, clearing, or lining existing stream channels. The purpose is to control floods, improve drainage, control erosion, or improve navigation. It is a very controversial practice that may have significant environmental impacts.
Synthesis of organic compounds by energy derived from chemical reactions.
Chernobyl, Ukraine
In April 1986 there was an explosive leak, caused by overheating, from a nonpressurized boiling-water reactor, one of the largest in Europe. The resulting clouds of radioactive material spread as far as the UK. Thirty-one people were killed in the explosion, and thousands of square kilometers of land were contaminated by fallout. By June 1992, seven times as many children in the Ukraine and Belarus were contracting thyroid cancer as before the accident, and the incidence of leukemia was rising; it was estimated that more than 6,000 people had died as a result of the accident, and that the death toll in the Ukraine alone would eventually reach 40,000.
Chlorofluorocarbons (CFCs)
Highly stable compounds that have been or are being used in spray cans as aerosol propellants and in refrigeration units (the gas that is compressed and expanded in a cooling unit). Emissions of chlorofluorocarbons have been associated with potential global warming and stratospheric ozone depletion.
An acute intestinal infection caused by ingestion of contaminated water or food.
Chronic Effects (Exposure)
Long-lasting results of exposure to a toxin; can be a permanent change caused by a single, acute exposure or a continuous, low-level exposure.
Short hairlike appendages found on the surfaces of some types of cells and organisms; used for either propelling trapped material out of the body or for locomotion.
stands for Convention on International Trade in Endangered Species (of Wild Fauna and Flora); this organization, which boasts a membership of 145 countries, bans commercial international trade in an agreed-upon list of endangered species, and regulates and monitors trade in others that might become endangered.
City Park
A natural, public, recreational area designed for urban cities.
City Planning
Conscious design of the growth and development of an urban area.
cutting - In timber harvesting, the practice of cutting all trees in a stand at the same time.
The representative or characteristic conditions of the atmosphere at particular places on Earth. Climate refers to the average or expected conditions over long periods; weather refers to the particular conditions at one time in one place.
Climax State
The final stage of ecological succession and therefore an ecological community that continues to reproduce itself over time, or a stage in ecological succession during which an ecological community achieves the greatest biomass or diversity. (The first definition is the classical definition.)
Closed Systems
A type of system in which there are definite boundaries to factors such as mass and energy such that exchange of these factors with other systems does not occur.
Colorado River
The Colorado River is a river in the southwestern United States and northwestern Mexico, approximately 1,450 mi (2,333 km) long, draining a part of the arid regions on the western slope of the Rocky Mountains. The natural course of the river flows into the Gulf of California, but the heavy use of the river as a fresh water source has desiccated the lower course of the river in Mexico such that it no longer reaches the sea.
A relationship between two kinds of organisms in which one benefits from the relationship and the other is neither helped nor hurt.
Commercial Forestry
In order to retain biodiversity in commercial forest, they must be managed in ways that simulate disturbances that take place in old growth forests, such as forest fires and storms. Over time, some of the structural characteristics of old-growth forests, such as old trees, deadwood and deciduous trees, can also be added.
land that belongs to the public, not to individuals. Historically a part of old English and New England towns where all the farmers could graze their cattle.
The situation that exists when different individuals, populations, or species compete for the same resource(s) and the presence of one has a detrimental effect on the other. Sheep and cows eating grass in the same field are competitors.
Competitive Exclusion Principle
The idea that two populations of different species with exactly the same requirements cannot persist indefinitely in the same habitat - one will always win out and the other will become extinct. Which one wins depends on the exact environmental conditions. Referred to as a principle, the idea has some basis in observation and experimentation.
Biochemical process in which organic materials, such as lawn clippings and kitchen scraps, are decomposed to a rich, soil-like material.
Confined Aquifer
An aquifer that is bound above and below by dense layers of rock and contains water under pressure.
Contour Farming (Plowing)
Plowing land along topographic contours, perpendicular to the slope—as much in the horizontal plane as possible, thereby decreasing the erosion rate.
control condition: the specimen that is used as an example in the experiment; a standard against which other conditions can be compared in a scientific experiment.
Control Rod
A device in the core of a reactor which absorbs neutrons, and is used to control the rate of fission and to stop the chain reaction.
Controlled Burning
Using prescribed fire to reduce the risk from wildfires, control tree diseases, increase food and habitat for wildlife, and manage forests for greater production of desirable tree species.
Controlled Experiment
A controlled experiment is designed to test the effects of independent variables on a dependent variable by changing only one independent variable at a time. For each variable tested, there are two set-ups (an experiment and a control) that are identical except for the independent variable being tested. Any difference in the outcome (dependent variable) between the experiment and the control can then be attributed to the effects of the independent variable tested.
Convergent Evolution
The process by which species evolve in different places or different times and, although they have different genetic heritages, develop similar external forms and structures as a result of adaptation to similar environments. The similarity in the shapes of sharks and porpoises is an example of convergent evolution.
Convergent Plate Boundary
Boundary between two lithosphere plates in which one plate descends below the other (subduction).
The innermost layer of the Earth, made up of mostly of iron and nickel. The core is divided into a liquid outer core and a solid inner core. The core is the densest of the Earth's layers.
Cosmopolitan Species
A species with a broad distribution, occurring whenever in the world the environment is appropriate.
Benefit Analysis- The examination of a public project and the evaluation of its total costs and benefits to all concerned.
Cracking Tower
The building structures where the distillation of oil occurs.
Crude Birth Rate
The annual number of live births per 1000 population, without regard to age or sex composition.
Crude Death Rate
The annual number of deaths per 1000 population, without regard to age or sex composition.
Crude Oil
Naturally occurring petroleum normally pumped from wells in oil fields. Refinement of crude oil produces most of the petroleum products we use today.
The outermost layer of rock the Earth.
A protozoan (single-celled organism) that can infect humans, usually as a result of exposure to contaminated drinking water.
Cultural Eutrophication
Eutrophication of lakes caused by human-induced processes, such as nutrient-rich sewage water entering a body of water, is called cultural eutrophication.
The unit used to describe the intensity of radioactivity in a sample of material. The curie is equal to 37 billion (3.7 x 1010) disintegrations per second, which is approximately the activity of 1 gram of radium. The Becquerel (Bq) has replaced the Ci in the SI system. The Becquerel (Bq) is 1 disintegration per second.
Cycling Rate
The amount of time required for a biogeochemical cycle to complete all phases of the cycle.
Cyclone Collector (Separator)
Instrument used to remove large particles (diameter greater than 3 m) from ambient air. The conical geometry of the collector subjects the air to rotation, and the centrifugal force leads to deposition of the particles. The particles can be sampled from the walls of the device for analysis, or simply removed physically from the airflow.
(Dichlorodiphenyltrichloroethane) a pesticide commonly used in the mid-1900s to control insect outbreaks. Breakdown elements from DDT and other pesticides called chlorinated hydrocarbons accumulated in the upper levels of the food chain. The results of this accumulation proved particularly hazardous for birds of prey and other bird species that eat primarily fish, because high quantities of these chemicals caused an abnormality in calcium production.
Death rate
The rate at which deaths occur in a population, measured either as the number of individuals dying per unit time or as the percentage of a population dying per unit time.
An organism that obtains its energy and nutritional requirements by feeding on dead organisms; or, a feeder on dead organisms.
Deductive Reasoning
Drawing a conclusion from initial definitions and assumptions by means of logical reasoning.
well Injection- A method of disposal of hazardous liquid waste that involves pumping the waste deep into the ground below and completely isolated form all freshwater aquifers. Deep-well disposal is a controversial method of waste disposal that is being carefully evaluated.
The removal of forest stands by cutting and burning to provide land for agricultural purposes, residential or industrial building sites, roads, etc., or by harvesting the trees for building materials or fuel.
Demographic Transition
The pattern of change in birth and death rates as a country is transformed from undeveloped to developed. There are three stages: (1) in an undeveloped country birth and death rates are high, and the growth rate is low; (2) the death rate decreases, but the birthrate remains high and the growth rate is high; (3) the birthrate drops toward the death rate and the growth rate therefore decreases.
The study of populations, especially their patterns in space and time.
The conversion of nitrate to molecular nitrogen by the action of bacteria - an important step in the nitrogen cycle.
Dependent Variable
A variable that changes in response to changes in an independent variable; a variable taken as the outcome, or dependent, variable.
The removal of salts from seawater or brackish water so that the water can be used for purposes such as agriculture, industrial processes, or human consumption.
An area, either hot or cold, where the annual precipitation is less than 25 cm (10 in).
The process of creating a desert where there was not one before. Farming in marginal grasslands, which destroys the soil and prevents the future recovery of natural vegetation, is an example of desertification.
Dead or decaying organic matter.
Developed (less developed) Nations
A less developed nation is a nation with a low income average, a relatively backwards infrastructure and a poor human development index when compared to the global norm.
Developed (more developed) Nations
A more developed nation is a nation that is technologically advanced and that enjoys a relatively high standard of living.
An organic compound composed of oxygen, hydrogen, carbon, and chlorine. About 75 types are known today. Dioxin is not normally manufactured intentionally but is a by-product resulting from chemical reactions in the production of other materials, such as herbicides. Known to be extremely toxic to mammals, its effects on the human body are being intensively studied and evaluated.
Direct Costs
In economics, costs borne by the producer and passed directly on to the user of purchaser.
Divergent Evolution
Organisms with the same ancestral genetic heritage migrate to different habitats and evolve into species with different external forms and structures, but typically continue to use the same kind of habitats. The ostrich and the emu are believed to be examples of divergent evolution.
Divergent Plate Boundary
Boundary between two lithosphere plates characterized by the production of new lithosphere; found along oceanic ridges.
DO (Dissolved Oxygen)
The amount of oxygen freely available in water and necessary for aquatic life and the oxidation of organic materials.
Dobson Unit
Commonly used unit to measure the concentration of ozone. One Dobson unit is equivalent to a concentration of 1 ppb ozone.
The Mauritius Dodo (Raphus cucullatus, called Didus ineptus by Linnaeus), more commonly just Dodo, was a meter-high flightless bird of the island of Mauritius. The Dodo, which is now extinct, lived on fruit and nested on the ground.
Refers to the amount of chemical that enters the body.
Dose Response Curve
A graph to show the relation between the dose of a drug and the degree of response it produces, as measured by the percentage of the exposed population showing a defined effect. If the effect determined is death, such a curve may be used to estimate an LD50 value.
Doubling Time
The time necessary for a quantity of whatever is being measured to double.
Removal of mud from the bottom of water bodies. This can disturb the ecosystem and cause silting that kills aquatic life. Dredging of contaminated mud's can expose biota to heavy metals and other toxics.
Drip Irrigation
Irrigation by the application of water to the soil from tubes that drip water slowly, greatly reducing the loss of water from direct evaporation and increasing yield.
E Horizon
Horizon that is composed of light-colored materials resulting from leaching of clay, calcium, magnesium, and iron to lower horizons. The A and E horizons together constitute the zone of leaching.
Early Successional Species
Species that occur only or primarily during early stages of succession. With vegetation, these are typically rapidly growing and short-lived with high reproductive rates.
Easter Island
One of the greatest mysteries on Earth are the statutes which stand on Easter Island. Easter Island is one of the most remote islands on Earth. It is in the southern Pacific Ocean, 2,300 miles west of the coast of Chile and 2500 miles southeast of Tahiti. The closest island is 1400 miles away, and that island is uninhabited. Easter Island is only 15 miles long and 10 miles wide. Yet, Easter Island, which was almost uninhabited when it was discovered on Easter Day in 1722 by a Dutch captain, is covered with hundreds of giant statutes, each weighing several tons and some standing more than 30 feet tall.
Ecological Island
An area that is biologically isolated so that a species occurring within the area cannot mix (or only rarely mixes) with any other population of the same species.
Ecological Justification (for the conservation of nature)
An argument for the conservation of nature on the grounds that a species, an ecological community, an ecosystem, or the Earth's biosphere provides specific functions necessary to the persistence of our life or of benefit to life. The ability of trees in forests to remove carbon dioxide produced in burning fossil fuels is such a public benefit and an argument for maintaining large areas of forests.
Ecological Niche
The general concept is that the niche is a species' "profession"—what it does to make a living. The term is also used to refer to a set of environmental conditions within which a species is able to persist.
The science of the study of the relationships between living things and their environment.
A community of plants, animals, and microorganisms that are linked by energy and nutrient flows and that interact with each other and with the physical environment. Rain forests, deserts, coral reefs, grasslands, and a rotting log are all examples of ecosystems.
ED 50
The effective dose or dose that causes an effect in 50% of the population on exposure to a particular toxicant. It is related to the onset of specific symptoms, such as loss of hearing, nausea, or slurred speech.
Edge Effect
An effect that occurs following the forming of a forest island; in the early phases the species diversity along the edge is greater than in the interior. Species escape from the cut area and seek refuge in the border of the forest, where some may last only a short time.
Electromagnetic Radiation
Radiation consisting of electric and magnetic waves that travel at the speed of light. Examples: light, radio waves, gamma rays, x-rays.
Electromagnetic Spectrum
Radiation consisting of electric and magnetic waves that travel at the speed of light. Examples: light, radio waves, gamma rays, x-rays.
Electrostatic Precipitator
An electrical device used in removing particles from combustion gases prior to release from a power plant's stack.
The migration of people out of a country.
Endangered Species
A species that faces threats that might lead to its extinction in a short time.
Endemic Species
A species that is native to a particular area.
Endocrine System
A system of ductless glands that regulates bodily functions via hormones secreted into the bloodstream. The endocrine system includes the hypothalamus, pituitary gland, thyroid, adrenal glands, and gonads (ovaries and testes).
Energy Efficiency
A measure of energy produced compared to energy consumed.
Energy Pyramid
A representation of the loss of useful energy at each step in a food chain.
(El Nino-Southern Oscillation) The term currently used by scientists to describe basin-wide changes every 2 to 7 years in air-sea interaction in the equatorial Pacific Ocean. El Niño/La Niña is the oceanic component and the Southern Oscillation is the atmospheric component of the phenomenon.
A measure in a system of the amount of energy that is unavailable for useful work. As the disorder of a system increases, the entropy in a system also increases.
Environmental Protection Agency (EPA)
A federal agency created in 1970 to permit coordinated and effective governmental action, for protection of the environment by the systematic abatement and control of pollution, through integration of research monitoring, standard setting, and enforcement activities.
Environmental Risk
Used in discussions of endangered species to mean variation in the physical or biological environment, including variations in predator, prey, symbiotic, or competitor species that can threaten a species with extinction.
Environmental Science
The scientific study that uses biological principles to look at the relationships between humans and their environment.
The study of the patterns, causes, and control of disease in groups of people.
Estimated Reserves
Estimated quantities of oil and gas which are not supported by geological or engineering data and are simply an educated estimation.
Increase in the concentration of chemical elements required for living things (i.e. phosphorus). Increased nutrient loading may lead to a population explosion of photosynthetic algae and blue-green bacteria that become so thick that light cannot penetrate the water. Plants deprived of light beneath the surface die; as they decompose, dissolved oxygen in the lake is lowered and eventually a fish kill may result. Eutrophication of lakes caused by human-induced processes, such as nutrient-rich sewage water entering a body of water, is called cultural eutrophication.
Even-aged Stands
Forest area where all live trees began growth from seeds and roots planted in about the same year.
The act of conducting a controlled test or investigation.
Exponential Growth
growth in which the rate of increase is a constant percentage of the current size; that is, the growth occurs at a constant rate per time period.
In economics, an effect not normally accounted for in the cost-revenue analysis of producers.
Disappearance of a life-form from existence; usually applied to a species.
During succession, one species prepares the way for the next (and may even be necessary for the occurrence of the next.)
A field that is allowed to grow with a cover crop without harvesting for at least one season.
Family Planning
Controlling reproduction; planning the timing of birth and having as many babies as are wanted and can be supported.
A sever shortage of food.
Fecal Coliform (Bacteria)
A standard measure of microbial pollution and an indicator of disease potential for a water source.
Feedlot Runoff
Contaminated runoff from a building where livestock are fattened for market or other farms.
A fishery (plural: fisheries) is an organized effort by humans to catch fish or other aquatic species, an activity known as fishing. Generally, a fishery exists for the purpose of providing human food, although other aims are possible (such as sport or recreational fishing), or obtaining ornamental fish or fish products such as fish oil. Industrial fisheries are fisheries where the catch is not intended for direct human consumption.
Flat topography adjacent to a stream in a river valley that has been produced by the combination of overbank flow and lateral migration of meander bends.
Food Chain
The linkage of who feeds on whom.
Food Web
A network of who feeds on whom or a diagram showing who feeds on whom.
Fossil Fuels
Forms of stored solar energy created from incomplete biological decomposition of dead organic matter. Include coal, crude oil, and natural gas.
Fractional Distillation
A process used to separate the parts of a liquid mixture due to differences in boiling points of the constituents.
Free Market Economy
A system where resources are owned by households: markets distribute resources through the price mechanism; and income depends upon the value of resources owned by an individual.
Fuel Rod
A long, slender tube that holds fuel (fissionable material) for nuclear reactor use. Fuel rods are assembled into bundles called fuel elements or fuel assemblies, which are loaded individually into the reactor core.
A chemical that kills fungi.
Gamma Rays
One of the three major kinds of nuclear radiation. A type of electromagnetic radiation emitted from the isotope similar to X rays but more energetic and penetrating.
Gene Pool
The total genetic information encoded in the total genes in a breeding population existing at a given time.
Generalist Species
A species with the ability to live in many different places while tolerating a wide range of environmental conditions.
Genetic Diversity
Variation among and within species that is attributable to differences in hereditary material.
Genetic Drift
Changes in the frequency of a gene in a population as a result of chance rather than of mutation, selection, or migration.
Genetic Engineering
The technique of removing, modifying, or adding genes to a DNA molecule in order to modify a specific organism for the purpose of changing one of its characteristics.
Genetic Risk
Used in discussions of endangered species to mean detrimental change in genetic characteristics not caused by external environmental changes. Genetic changes can occur in small populations from such causes as reduced genetic variation, genetic drift, and mutation.
Giant Panda
A large black-and-white herbivorous mammal of bamboo forests of China and Tibet that has become an endangered species.
Glen Canyon Dam
A dam on the Colorado River at Page, Arizona. The dam has been controversial since its inception, because it caused the flooding of Glen Canyon to create a man-made reservoir, Lake Powell.
Global Extinction
Disappearance or extinction of a species everywhere.