Environmental Problems, Their Causes, and Sustainability 1

fundamental niche The full potentialrange of the physical, chemical, and biologicalfactors a species can use if there is nocompetition from other species. See ecologicalniche. Compare realized niche.fungicide Chemical that kills fungi.Gaia hypothesis Hypothesis that theearth is alive and can be considered a systemthat operates and changes by feedbackof information between its living and nonlivingcomponents.gamma rays A form of ionizing electromagneticradiation with a high energy contentemitted by some radioisotopes. Theyreadily penetrate body tissues. See alsoalpha particle, beta particle.gangue Waste or undesired material in anore. See ore.GDP See gross domestic product.gene flow Movement of genes betweenpopulations, which can lead to changes inthe genetic composition of local populations.gene mutation See mutation.gene pool The sum total of all genesfound in the individuals of the populationof a particular species.generalist species Species with a broadecological niche. They can live in manydifferent places, eat a variety of foods, andtolerate a wide range of environmental conditions.Examples are flies, cockroaches,mice, rats, and human beings. Comparespecialist species.genes Coded units of information aboutspecific traits that are passed on from parentsto offspring during reproduction. Theyconsist of segments of DNA moleculesfound in chromosomes.gene splicing See genetic engineering.genetic adaptation Changes in thegenetic makeup of organisms of a speciesthat allow the species to reproduce and gaina competitive advantage under changedenvironmental conditions. See differentialreproduction, evolution, mutation, naturalselection.genetically modified organism (GMO)Organism whose genetic makeup has beenmodified by genetic engineering.genetic diversity Variability in thegenetic makeup among individuals within asingle species. See biodiversity. Compare ecologicaldiversity, functional diversity, speciesdiversity.genetic drift Change in the genetic compositionof a population by chance. It isespecially important for small populations.genetic engineering Insertion of an aliengene into an organism to give it a beneficialgenetic trait. Compare artificial selection,natural selection.genome Complete set of genetic informationfor an organism.geographic isolation Separation of populationsof a species for long times intodifferent areas.geology Study of the earth’s dynamic history.Geologists study and analyze rocksand the features and processes of the earth’sinterior and surface.geothermal energy Heat transferred fromthe earth’s underground concentrations ofdry steam (steam with no water droplets),wet steam (a mixture of steam and waterdroplets), or hot water trapped in fracturedor porous rock.global climate change Abroad term thatrefers to changes in the earth’s climatemostly as a result of changes in temperatureand precipitation.globalization Broad process of globalsocial, economic, and environmental changethat leads to an increasingly integratedworld. See information and globalization revolution.global warming Warming of the earth’satmosphere because of increases in theconcentrations of one or more greenhousegases primarily as a result of human activities.See greenhouse effect, greenhouse gases.grassland Biome found in regions wheremoderate annual average precipitation(25–76 centimeters, or 10–30 inches) isenough to support the growth of grass andsmall plants but not enough to supportlarge stands of trees. Compare desert, forest.greenhouse effect A natural effect thatreleases heat in the atmosphere (troposphere)near the earth’s surface. Watervapor, carbon dioxide, ozone, and severalother gases in the lower atmosphere (troposphere)absorb some of the infrared radiation(heat) radiated by the earth’s surface.This causes their molecules to vibrate andtransform the absorbed energy into longerwavelengthinfrared radiation (heat) in thetroposphere. If the atmospheric concentrationsof these greenhouse gases rise andthey are not removed by other naturalprocesses, the average temperature of thelower atmosphere will increase gradually.Compare global warming. See also naturalgreenhouse effect.greenhouse gases Gases in the earth’slower atmosphere (troposphere) that causethe greenhouse effect. Examples are carbondioxide, chlorofluorocarbons, ozone,methane, water vapor, and nitrous oxide.green manure Freshly cut or still-growinggreen vegetation that is plowed into the soilto increase the organic matter and humusavailable to support crop growth. Compareanimal manure.green revolution Popular term for introductionof scientifically bred or selectedvarieties of grain (rice, wheat, maize) that,with high enough inputs of fertilizer andwater, can greatly increase crop yields.gross domestic product (GDP) Annualmarket value of all goods and servicesproduced by all firms and organizations,foreign and domestic, operating within acountry.gross primary productivity (GPP) Therate at which an ecosystem’s producers captureand store a given amount of chemicalenergy as biomass in a given length of time.Compare net primary productivity.ground fire Fire that burns decayedleaves or peat deep below the ground surface.Compare crown fire, surface fire.groundwater Water that sinks into the soiland is stored in slowly flowing and slowlyrenewed underground reservoirs calledaquifers; underground water in the zone ofsaturation, below the water table. Comparerunoff, surface water.habitat Place or type of place where anorganism or population of organisms lives.Compare ecological niche.habitat fragmentation Breakup of a habitatinto smaller pieces, usually as a result ofhuman activities.half-life Time needed for one-half of thenuclei in a radioisotope to emit its radiation.Each radioisotope has a characteristic halflife,which may range from a few millionthsof a second to several billion years. Seeradioisotope.hazard Something that can cause injury,disease, economic loss, or environmentaldamage. See also risk.hazardous chemical Chemical that cancause harm because it is flammable orexplosive, can irritate or damage the skin orlungs (such as strong acidic or alkaline substances),or can cause allergic reactions ofthe immune system (allergens). See alsotoxic chemical.hazardous waste Any solid, liquid, orcontainerized gas that can catch fire easily,is corrosive to skin tissue or metals, isunstable and can explode or release toxicfumes, or has harmful concentrations of oneor more toxic materials that can leach out.See also toxic waste.heat Total kinetic energy of all the randomlymoving atoms, ions, or moleculeswithin a given substance, excluding theoverall motion of the whole object. Heatalways flows spontaneously from a hotsample of matter to a colder sample of matter.This is one way to state the second lawof thermodynamics. Compare temperature.herbicide Chemical that kills a plant orinhibits its growth.herbivore Plant-eating organism. Examplesare deer, sheep, grasshoppers, and zooplankton.Compare carnivore, omnivore.heterotroph See consumer.high An air mass with a high pressure.Compare low.high-input agriculture See industrializedagriculture.high-quality energy Energy that is concentratedand has great ability to performuseful work. Examples are high-temperatureheat and the energy in electricity, coal,oil, gasoline, sunlight, and nuclei of uranium-235.Compare low-quality energy.high-quality matter Matter that is concentratedand contains a high concentrationof a useful resource. Compare low-qualitymatter.G8GLOSSARY