| A | B |
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| Abiotic | Nonliving or not containing any living organisms |
| Acid fallout | Molecules of acid formed from reactions high in the atmosphere involving nitrogen, sulfur oxides, and water vapor that settle out of the atmosphere without any additional water |
| Aerobic | Living or occurring only in the presence of oxygen: aerobic bacteria. 2. Of or relating to aerobes, organisms that require and utilize oxygen. 3. Involving or improving oxygen consumption by the body: aerobic exercise. |
| Autotroph | Literally, "self eater." Organisms capable of producing their own food. |
| Bioaccumulation | An increase in the concentration of a chemical in specific organs or tissues at a level higher than would normally be expected. |
| Biodegradable | Able to be broken down into simpler substances (elements and compounds) by naturally occuring decomposers. Essentially, anything that can be ingested by an organism without causing that organism harm. |
| Biome | A specific type of terrestrial region inhabited by well-defined types of life, especially zones of vegetation, that generally cannot live outside that specific region. Examples include types of deserts ("high desert" like the Mojave or "low desert" like the Chihuahua), grasslands (prairies, coastal dunes), and forests (lodgepole pine vs. taiga; temperate rain forest; bamboo forest, tropical rain forest, cloud forest, etc.). |
| Carrying capacity | The amount of animal or plant life (or industry) that can be supported indefinitely on available resources; the number of individuals that the resources of a habitat can support. Also called biological carrying capacity. |
| Conservation biology | Multidisciplinary science created to deal with the crisis of maintaining the genes, species, communities, and ecosystems that make up earth's biological diversity. Its goals are to investigate human impacts on biodiversity and to develop practical approaches to preserving biodiversity and ecological integrity. |
| Conservation-tillage farming | Crop cultivation in which the soil is disturbed little (minimum-tillage farming) or not at all (no-till farming) to reduce soil erosion, lower labor costs, and save energy. |
| Cost-benefit analysis | Estimates and comparison of short-term and long-term costs (losses) and benefits (gains) from an economic decision. If the estimated benefits exceed the estimated costs, the decision to buy an economic good or provide a public good is considered worthwhile. |
| Deforestation | Removal of trees from a forested area without adequate replanting. |
| Desertification | Conversion of rangeland, rain-fed cropland to desert-like land, with a drop in agricultural productivity of 10% or more. It is usually caused by a combination of overgrazing, soil erosion, prolonged drought, and climate change. |
| Dioxin | A synthetic, organic chemical of the chlorinated hydrocarbon class. It is one of the most toxic compounds known to humans, having many harmful effects, including induction of cancer and birth defects, even in extremely minute concentrations. It has become a widespread environmental pollutant because of the use of certain herbicides that contain dioxin as a contaminant. |
| Ecological efficiency | The percentage of energy in biomass produced by one trophic level that is incorporated into biomass by the next highest trophic level. |
| Ecological fitness | The number of a parent's young that live to reproduce; divided by two if sexual reproduction is involved. |
| Ecological succession | Process in which communities of plant and animal species in a particular area are replaced over time by a series of different and often more complex communities. |
| Ecosystem | An ecological community of various plants, animals, and other organisms, interacting with each other and with the nonliving resources in their environment, all functioning as a unit. |
| Ecotourism | The enterprises involved in promoting tourism of unusual or interesting ecological sites. Environmentally, culturally, and scientifically responsible tourism that takes great efforts to ensure tourism revenues benefit the local communities where tourism occurs, the local inhabitants benefit the most economically (revenues are not returned to the traveler's country of origin) and native culture is not diluted with imported tourist cultures. Ecotourism safeguards the nature of the attraction that instigated the tourism and serves to strengthen conservation and scientific research efforts in the area. Very few large corporations who claim to engage in ecotourism actually do so. The most notorious and damaging of tourism industries -- the cruise line industry -- is an excellent example of a branch of travel that claims to be environmentally-friendly but is in fact extremely damaging, both culturally and ecologically. |
| Emerging disease | The Institute for Medicine defines emerging and re-emerging diseases as: "New, re-emerging, or drug-resistant infections whose incidence in humans has increased in the last two decades or whose incidence threatens to increase in the near future." |
| Endangered species | Wild species with so few individual survivors that the species could soon become extinct in all or most of its natural range. |
| Environment | All external conditions and factors, living and nonliving (chemicals and energy), that affect an organism or other specified system during its lifetime; the earth's life-support systems for us and for all other forms of life - in effect another term for describing solar capital and earth capital. |
| Exponential growth | Growth in which some quantity, such as population size or economic output, increases by a fixed percentage of the whole in a given time; when the increase in quantity over a long enough time is plotted, this type of growth typically yields a curve shaped like the letter J. |
| Extinct | A species that is no longer living on earth. All representatives of the species are dead. All the species that once occupied the earth but are no longer living are extinct. We know of their existence through studying the fossil record . Compare to extant . |
| Food chain | Figure of speech describing the dependence of heterotrophs on other organisms for food, progressing in a series beginning with primary producers (plants) and ending with the largest carnivores. The food chain is used as a figurative image for educational purposes only... real trophic systems resemble webs rather than chains. |
| Fossil | remnant, impression, mineralized mold, amber encasement, or other trace of a once-living organism. Technically, anything that once lived and has been permanently preserved is a fossil, but the most common usage implies great age. This common usage of fossil generally refers to the mineralized remains or impressions, preserved in stone (almost always sedimentary rock), of extinct organisms from past geologic ages. |
| Gene pool | The sum total of all the genes that exist among all the individuals of a species. |
| Geology | The branch of science that deals with the earth's history, particularly its physical history, as recorded in the substrate and the fossil record . |
| Global warming | The term given to the possibility that Earth's atmosphere is gradually warming because of the greenhouse effect of carbon dioxide and other gases. Global warming is thought by many to be the most serious global environmental issue facing our society. |
| Greenhouse effect | A natural effect that traps heat in the atmosphere (troposphere) near the earth's surface. Some of the heat flowing back toward space from the earth's surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the lower atmosphere (troposphere) and then radiated back toward the earth's surface. If the atmospheric concentrations of these greenhouse gases rise and are not removed by other natural processes, the average temperature of the lower atmosphere will gradually increase. |
| Green Revolution | Refers to the development and introduction of new varieties of wheat and rice (mainly) that increased yields per acre dramatically in some countries. |
| Hazardous waste | Any solid, liquid, or containerized gas that can catch fire easily, is corrosive to skin tissue or metals, is unstable and can explode or release toxic fumes, or has harmful concentrations of one or more toxic materials that can leach out. |
| Heterotroph | Literally, "eats others." An organism that must consume other organisms to fuel its metabolism. Animals, including humans, are heterotrophs. |
| Hybrid | The offspring of two parents from separate (though closely related) species. Usually sterile, though occassionally able to breed back into one of the parent lines. A hybrid can almost never produce viable offspring when mated with another hybrid. A common example is a mule, which is produced by breeding a horse with a donkey (note that the horse must be the mother, due to the large size of the foal). Hybridization is fairly common among wind-pollinated plants, while hybridization is quite uncommon among higher animals. |
| Interspecific competition | Members of two or more species trying to use the same limited resources in an ecosystem. |
| Keystone species | Species that play roles affecting many other organisms in an ecosystem. |
| Lichen | A symbiotic relationship between a fungus and a moss. The moss does most of the work, producing sugars for the lichen's collective metabolic pathways. Lichen are generally low-growing, vary in color from bright orange or yellow to gray or black, and are often found growing on rocks and tree bark. An easy mnemonic to assist recall of the nature of a lichen's symbiosis is: "A fungus took a likin' to a moss, and now they live together." |
| Mutualism | One category of symbiosis in which both participating species generally benefit. |
| Natural resources | Nutrients and minerals in the soil and deeper layers of the earth's crust; water; wild and domestic plants and animals; air; and other resources produced by the earth's natural processes. |
| Natural selection | One of several gradual mechanisms through which evolution occurs. Process by which a particular beneficial gene (or set of genes) is reproduced more than other genes in succeeding generations due to selective pressures in the environment that favor the beneficial gene. The result of natural selection is a population that contains a greater proportion of organisms better adapted to certain environmental conditions |
