GLOSSARY OF ECOLOGY TERMS

Ecology is the wide-sweaping study of the relationships between organisms and their environments. This includes the interactions of living organisms with one another and with their non-living surroundings, the flow of matter and energy in environments, and the structure and functions of nature.

Many branches of enquiry in the physical and medical sciences are subsets of this larger discipline... seeking to understanding how components of a given system interact with one another and why they behave the way they do.

Our glossary contains most of the scientific terms you'll encounter while using this site:

A-D | E-H | G-M | N-S | T-Z

A | B | C | D

 

Abiotic, adj: Nonliving or not containing any living organisms.

Abiotic factors, n: Environmental influences produced other than by living organisms; for example, temperature, wind patterns, humidity, pH, substrate rock type, and other physical and chemical influences.

Absolute poverty, n: The lack of sufficient income in cash or exchange items for meeting the most basic needs of food, clothing, and shelter.

Acid fallout, n: 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.

Acid precipitation, n: Includes acid rain, acid fog, acid snow, and any other form of precipitation that is more acidic that normal (i.e., less that pH 5.6). Excess acidity is derived from certain air pollutants, namely sulfur dioxide and oxides of nitrogen. The effects can include: fish kills and eutrophication of lakes; tree kills, leading to soil erosion; and physical corrosive damage to vehicles and buildings. Many historic buildings in Europe and the NE United States are suffering damage from severe corrosion due to acid precipitation.

Aerobe, n: An organism that utilizes atmospheric oxygen (0 2 ) in its metabolic pathways. An organism that must have oxygen in order to survive is an obligate aerobe .

Aerobic, adj: 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.

top of page

Agroforestry, n: Production of tree crops in a manner similar to agriculture. Also, production of trees along with regular crops.

Anaerobe, n.: 1: An organism capable of living in the absence of free oxygen (O2 ). 2: Obligate anaerobe: An organism that must live without oxygen, for whom oxygen (O2 ) is toxic.

Anaerobic, adj.: 1: Lacking or seriously depleted of oxygen. Opposite of aerobic. 2: Of or relating to organisms, such as certain bacteria, that can live in the absence of atmospheric oxygen (indeed, for most anaerobic bacteria, oxygen is toxic).

Autotroph, n: Literally, "self eater." Organisms capable of producing their own food. See primary producers . Contrast with heterotroph .

top of page

B

Background extinction rate, n: Normal rate of extinction -- as a natural part of the evolutionary process -- of various species as a result of changes in local environmental conditions and the actions of natural evolutionary forces. Extinctions not caused or contributed to by the actions of humans.

Bioaccumulation, n: An increase in the concentration of a chemical in specific organs or tissues at a level higher than would normally be expected.

Biodegradable, adj: 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. 2. Nontoxic and able to be decomposed in relatively short period even on a human time scale .

Biodiversity, n: The variety of biotic factors found within a specified geographic region. 2. The combined differences of living things, generally classified in four broad categories:

• Genetic Diversity: Variety among individuals within a species -- or, more specifically, the variety in the DNA of a species. See also "alleles."
• Species Diversity: Variety of different organisms at the species taxonomic level. See also species and taxonomy .
• Cultural Diversity: Variety of learned behaviors among individuals of a species.
• Ecosystem Diversity: Variety of biomes and habitats occuring in the biosphere.

top of page

Binomial nomenclature, n: The two-name system, developed by Carolus Linnaeus (the founder of modern taxonomy), used to assign scientific names to all living things. Homo sapiens, for example, is the scientific name for humans. The first name is the genus name and is always capitalized. This is sort of like your last name... it belongs to several of your close relatives, too, and it shows that you are all closely related. The second name is the species name is always lower case. This is like your first name, which no one else in your circle of relatives posseses and so it uniquely identifies you. Memory tool: you probably know the meanings of the terms generic (i.e. general, broad) and specific (i.e. precise, exact). These terms come from the same origins as genus and species, so recalling their meaning will help you recall the relationship between the two portions of a scientific name.

Biome, n: 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.).

Bionomics, n: See ecology .

Biosphere, n: The portion of the earth and its atmosphere in which living organisms exist or that is capable of supporting life. 2. All of earth's ecosystems combined into one inclusive unit. Also called the "ecosphere." 3. The living organisms and their environment composing the biosphere. "...all life on earth and the realms that support it, from the outermost reaches of the atmosphere to the deepest trenches of the seas." National Geographic Atlas of the World, 6th Edition.

top of page

C

Carrying capacity, n: 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, n: 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, n: 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.

Coral bleaching, n: The loss of color from a coral as it expels its zooxanthellae-usually a stress response.

Cost-benefit analysis, n: 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.

top of page

D

Debt-for-nature swap, n: Agreement in which a certain amount of foreign debt is canceled in exchange for local currency investments that will improve natural resource management or protect certain areas in the debtor country from harmful development.

Deforestation, n: Removal of trees from a forested area without adequate replanting.

Demographic transition, n: Hypothesis that countries, as they become industrialized, have declines in death rates followed by declines in birth rates.

Desertification, n: 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, n: 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.

Acknowledgements

Many thanks to Troy Knott and Catherine Burr for their hard work in assisting to compile this glossary.