 | Term | Definition |
| |
abiotic |
Nonliving. |
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abiotic interactions |
Interactions between organisms and nonliving components of the environment. |
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biotic |
Having to do with life or living organisms. |
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biotic interactions |
Interactions between organisms and living components of the environment. |
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population densities |
Numbers of individuals in a population relative to the area in which they live. |
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population structure |
Distribution of species in different age groups and different areas. |
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population dynamics |
Patterns which affect growth or change within a population. |
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community |
A group of organisms inhabiting the same region and interacting with each other. |
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competition |
Type of interaction between organisms when resources (like food, mates, shelters, etc.) are scarce. |
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predation |
When one species feeds on another species. |
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predator |
Any animal that lives by killing and eating on other animals. |
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prey |
An organism that is killed and eaten by another as food. |
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parasitism |
Interaction between organisms from different species in which one member depends on the other for its life functions; the dependent member (the parasite) benefits from the relationship while the other (the host) is harmed by it. |
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parasite |
An organism that takes nutrients from another living organism (the host), without giving that organism anything in return. |
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host |
An organism that is infected with or fed upon by a parasitic or pathogenic organism. |
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amensalism |
Type of interaction between organisms in which one organism is unaffected and the other suffers. |
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commensalism |
Type of interaction where one organism benefits while the other is neither harmed nor benefited. |
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mutualism |
Interdependent interaction between organisms in which all the organisms involved benefit. |
| |
disturbance |
An event that affects the survival of some or all of the species in a community. |
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ecological succession |
The gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established. |
| |
primary succession |
The initial colonization of barren or sterile areas by organisms; examples include vegetation growth on lava newly formed lava flows. |
| |
secondary succession |
The series of community changes which take place on a previously colonized, but disturbed or damaged habitat; examples include areas which have been cleared of existing vegetation by floods or fires. |
| |
pioneer species |
The first organisms to colonize an area after a disturbance. |
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shade intolerant species |
Plants that grow best in open sun. |
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shade tolerant species |
Plants that grow well in the shade. |
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intermediate disturbance hypothesis |
The theory that diversity is maximized through moderate amounts of disturbance. |
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density dependent factors |
Factors which affect the population of a species due to the actual population size of the species; some examples are increased predation (higher frequency falling to prey) and shortage of food. |
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density independent factors |
Factors which affect the population regardless of its population size; usually from abiotic causes such as forest fires. |
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environmental carrying capacity |
The maximum population size that can be supported indefinitely by a given environment. |
| |
logistical growth |
Population growth pattern that begins with rapid growth, and slows down as the environmental carrying capacity is reached; characterized by an S-shaped curve when graphed. |
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resources |
Available supplies that can be drawn on when needed. |
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ecology |
The study of the interactions among organisms and between organisms and their environment. |
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natural resource |
A substance created by natural processes that humans obtain from the environment. |
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nonrenewable resource |
A resource that cannot be replenished by natural processes in any reasonable time period. |
| |
renewable resources |
Natural resources that can regenerate themselves if alive, and replenish themselves through chemical cycles if they're not alive. |
| |
perpetual resources |
Renewable resources that can be rapidly replaced through short term natural processes and can therefore be considered inexhaustible. |
| |
potentially renewable resources |
Resources that can renew themselves over a short period of time, but that can be damaged or overused to the extent that they're no longer capable of replenishing themselves. |
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fossil fuel |
A hydrocarbon deposit, such as petroleum, coal, or natural gas, derived from living matter millions of years ago and used for energy. |
| |
rangeland |
Land that has the primarily purpose of feeding grazing animals. |
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carrying capacity |
The maximum number of organisms that can be supported by a given area of land. |
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overgraze |
To permit animals to graze excessively, to the detriment of the vegetation. |
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erosion |
The process by which soil and other materials are worn away from the Earth's surface. |
| |
biofuels |
Fuels, such as ethanol or methanol, that are created from the fermentation of plants or plant products. |
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atmosphere |
The layer of gas surrounding the Earth. |
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troposphere |
The layer of the Earth's atmosphere that is closest to the earth's surface. |
| |
stratosphere |
The middle layer of the Earth's atmosphere. |
| |
mesosphere |
Outermost layer of the Earth's atmosphere. |
| |
surface water |
The liquid water sitting on top of the land in the major water bodies. |
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groundwater |
The water that penetrates the Earth's surface and seeps into deeper levels of the crust. |
| |
aquifers |
Underground stores of water. |
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watershed |
The area of land from which water and sediments are transported into a major stream or stream system. |
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pollution |
The contamination of soil, water, and the atmosphere by the discharge of harmful substances. |
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pollutants |
Substances that make the environment unfit for or harmful to living things. |
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degradable pollution |
Pollution that can be quickly broken down by natural processes, such as by bacteria or other microorganisms. |
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persistent pollution |
Pollution that cannot be broken down quickly, taking many years to disappear from the environment. |
| |
nondegradable pollution |
Pollution that cannot be broken down through natural processes over any reasonable time period. |
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point source pollutants |
Pollutants that come from a few clearly identifiable sources. |
| |
non-point source pollutants |
Pollutants that come from many widely dispersed sources. |
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Environmental Protection Agency |
EPA |
| |
National Ambient Air Quality Standards |
NAAQS |
| |
wetlands |
Land that is shallowly covered by surface or ground water often enough to support the growth of plants that live in water-saturated soil; examples include swamps, marshes, and bogs. |
| |
biomagnification |
Process by which poisons become more concentrated in animal and plant tissue as they move higher in the food web. |
| |
deforestation |
Loss or change of forest habitat. |
| |
desertification |
The process by which productive lands are converted to deserts, often through poor agricultural practices. |
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greenhouse gases |
Gases like methane and carbon dioxide which trap heat between the earth and the lower atmosphere. |
| |
greenhouse effect |
The trapping of infrared light reflected off the earth's surface, by gaseous molecules in the Earth's atmosphere. |
| |
halons |
Molecules that contain carbon and one of the halogen atoms. |
| |
halogen |
A family of elements that includes fluorine, chlorine, bromine, iodine, and astatine. |
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