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HLSC114 EcologyTerms
50 Key Ecological Terms needed for Midterm
Term | Definition |
---|---|
Abiotic | Nonliving or not containing any living organisms |
Acceptable daily intake (ADI) | is a measure of the amount of a specific substance that can be ingested (orally) over a lifetime without an appreciable health risk |
Bioaccumulation | An increase in the concentration of a chemical in specific organs or tissues at a level higher than would normally be expected. |
Biodiversity | The variety of biotic factors found within a specified geographic region. |
Biomagnification | the process whereby certain substances such as pesticides or heavy metals become concentrated in tissues or internal organs as they move up the chain because the substances are very persistent and stable. |
Biome | Complex communities characteristic of a regional climatic zone. |
Biosphere | The portion of the earth and its atmosphere in which living organisms exist or that is capable of supporting life. |
Biotic community | Natural grouping of various plant and animal species within a given habitat. |
Biotic potential | the maximum reproductive capacity of a population if resources are unlimited. Full expression of the biotic potential of an organism is restricted by environmental resistance. |
Carcinogen | any substance or radiation, that is directly involved in the development or spread of cancer. |
Carrying capacity | The amount of organisms that can be supported indefinitely on available resources |
Climax community | A relatively stable, self-perpetuating biotic community |
Chronic toxicity | the toxic, or harmful, effects of a substance on a living organism due to continuous, repeated, or long-term exposure. |
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. |
Decomposer | organisms that break down dead or decaying organisms, and in doing so carry out the natural process of decomposition. |
Deforestation | Removal of trees from a forested area without adequate replanting. |
Demographic transition | Hypothesis that countries, as they become industrialized, have declines in death rates followed by declines in birth rates. |
Desertification | Conversion of rangeland or cropland to desert-like land, with a drop in agricultural productivity of 10% or more. |
Ecological dominant | Organisms that largely control the flow of energy through a community. |
Ecological succession | The gradual replacement of one biotic community by another over time. |
Ecosystem | A natural area where living things interact with the chemical and physical environment. |
Emissions trading (also known as cap and trade) | is a market-based approach used to control pollution by providing economic incentives for achieving reductions in the emissions of pollutants. |
Environmental degradation | A reduction of an ecosystem's ability to support its natural biotic community. |
Environmental Justice | The fair tx of people of all races and incomes w/ respect to development, implementation, and enforcement of env. laws, regulations, and policies. |
Eutrophication | Excessive nutrients in a body of water, usually caused by runoff , which causes a dense growth of plant life; the decomposition of the plants depletes the supply of oxygen, leading to the death of animal life |
Exotic species | Nonnative organisms introduced into an established biotic community. |
Food defect action levels | the accepted level of natural or unavoidable defects that present no health hazards for humans. Food defect action levels are published by the US Food and Drug Administration. |
Greenhouse effect | A natural effect that traps heat in the troposphere near earth's surface. If the atmospheric concentrations of these greenhouse gases rise and are not removed by other natural processes, the average temp of the lower atmosphere will gradually increase. |
Homeostatic control | The physiological capacity of an organism to regulate itself by rapidly restoring internal conditions following a sudden perturbation in the external environment |
Integrated pest management (IPM) | Combined use of biological, chemical, and cultivation methods in proper sequence and timing to keep the size of a pest population below the size that causes economically unacceptable loss of a crop or livestock animal. |
Inversion layer | A layer of warm air in the atmosphere that prevents the rise of cooling air and traps pollutants beneath it. |
Keystone predator | Animal species that moderate competition among prey species, thereby maintaining greater diversity within the community. |
Kwashiorkor, n | Type of malnutrition that occurs in infants and very young children when they are weaned from mother's milk to a starchy diet low in protein. |
Limiting factors | Environmental conditions that control where an organism can live. |
Lowest observable effect level (LOEL) | The lowest concentration or amount of a substance found by experiment or observation which causes an adverse effect on the target organism. |
Marasmus | Nutritional-deficiency disease caused by a diet that does not have enough calories and protein to maintain good health. |
Niche diversification | Adaptations to life in a specific environment that reduce competition among species for food and living space. |
Ozone (O3) or trioxygen | is a triatomic molecule, consisting of three oxygen atoms. |
Ozone layer | a layer in the stratosphere (at approximately 20 miles) that contains a concentration of ozone sufficient to block most ultraviolet radiation from the sun |
Particulate Matter (PM) | Solid or liquid particles of soot, dust, smoke, fumes, and aerosols. |
Pest | An organism which is detrimental to humans or human concerns. |
Pesticide | Any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest |
Pollutant | A particular chemical or form of energy that can adversely affect the health, survival, or activities of humans or other living organisms. |
Population | Individuals of the same species living together within a given area. |
Population change, n | An increase or decrease in the size of a population. It is equal to (births + immigration) - (deaths + emigration). |
Precautionary principle | env. policy position that states that if an action has a suspected risk of causing harm to the public/environment, w/o scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking the action. |
Radon | a chemical element that is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as the decay product of radium. |
T value (or T level) | For a specific soil, the maximum average annual soil loss expressed as tons per acre per year that will permit current production levels to be maintained economically and indefinitely; the soil loss tolerance level. |
Teratogen | Any agent that can disturb the development of an embryo or fetus. Teratogens may cause a birth defect in the child or may halt the pregnancy outright. The classes of teratogens include radiation, maternal infections, chemicals, and drugs |
Trophic level | The relative position occupied by an organism in a food chain. |