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Ecology: Glossary

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Glossary of ecology.

Referenced material is from A Glossary of Terms Related to Basic Ecology (Ecology - Wikibooks - the Creative Commons Attribution-ShareAlike License), most other defimnitions from Wikipedia - Glossary of ecology Creative Commons Attribution-ShareAlike License . A few terms have been added or modified.

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Abiotic factors The non-biological environmental influences that affect organisms; for example, temperature, rainfall, and humidity. Wikipedia glossary

Autopoïesis An organized self contained system whose parts and systems integrate seamlessly in a relationship of form and function.

Autotroph an organism who makes its own food from inorganic materials.. Wikipedia glossary


Biodiversity diversity of species in an environment; variety of organisms found within a specified geographical region. Wikipedia glossary

Biogeography the study of the distribution of organisms and species, past and present, and of diverse processes that underlie their distribution patterns. The patterns of species distribution at this level can usually be explained through a combination of historical factors such as speciation, extinction, continental drift, glaciation (and associated variations in sea level, river routes, and so on), and river capture, in combination with the area and isolation of landmasses (geographic constraints) and available energy supplies. Wikipedia

Biogeochemistry effect of biota on global chemistry, and the cycles of matter and energy that transport the Earth's chemical components in time and space. Wikipedia glossary

Biogeochemical cycle the pathway through which a chemical, element, or molecule moves through the atmosphere, hydrosphere, lithosphere, and biosphere. Wikipedia glossary

Biomass the sum of all living living organisms in an area; a measure of the quantity of living matter in a given unit area or volume. Wikipedia glossary

Biome The total complex of biotic communities occupying and characterizing a particular area or zone, classified according to its climate and type of vegetation. More Wikipedia glossary

Biological control or biocontrol 1. In general, the control of the numbers of one organism as a result of natural predation by another or others. Specifically, the human use of natural predators for the control of pests or weeds. Also applied to the introduction of large numbers of sterilized males of the pest species, whose matings result in the laying of infertile eggs (Allaby, 1998). 2. The release of one species to control another (Carlton, 2001). 3. The management of weeds using introduced herbivores (often insects) as biological control agents (Booth et al., 2003). 4. Control method involving a biological control agent that is a natural enemy of a target pest (Heutte and Bella, 2003).

Biological diversity or biodiversity Used to describe species richness, ecosystem complexity, and genetic variation (Allaby 1998).

Bioregion A biological subdivision of the earth's surface delineated by the flora and fauna of the region (Allaby 1998).

Biota The plants and animals of a specific region or period, or the total aggregation of organisms in the biosphere (Allaby 1998); the total collection of organisms of a geographic region or a time period. More

Biotic factors The living environmental influences that affect organisms, such as predators, competitors, prey. Wikipedia glossary

Biosphere The sphere of life; all living organisms on the planet and their interactions, Wikipedia glossary


Community Any grouping of populations of different organisms that live together in a particular environment (Allaby 1998). A Biocenose, or community, is a group of populations of plants, animals, micro-organisms. Each population is the result of procreations between individuals of same species and cohabitation in a given place and for a given time. When a population consists of an insufficient number of individuals, that population is threatened with extinction; the extinction of a species can approach when all biocenoses composed of individuals of the species are in decline. In small populations, consanguinity (inbreeding) can result in reduced genetic diversity that can further weaken the biocenose. Biotic ecological factors also influence biocenose viability; these factors are considered as either intraspecific and interspecific relations.


Disturbance An event or change in the environment that alters the composition and successional status of a biological community and may deflect succession onto a new trajectory, such as a forest fire or hurricane, glaciation, agriculture, and urbanization (Art 1993).


Ecology The study of the interactions of organisms with their environment and with each other. Wikipedia glossary

Ecosystem A discrete unit, or community of organisms and their physical environment (living and non-living parts), that interact to form a stable system (Allaby 1998).

Endemic A species or taxonomic group that is restricted to a particular geographic areas because of such factors as isolation or response to soil or climatic conditions; this species is said to be endemic to the place (Allaby 1998) and would be native.

Exotic species This term is commonly used in publications and literature, and is similar to the terms alien species, foreign species, introduced species, non indigenous species, and non native species (Heutte and Bella 2003). Other definitions include: 1. An introduced, non native species, or a species that is the result of direct or indirect, deliberate or accidental introduction of the species by humans, and for which introduction permitted the species to cross a natural barrier to dispersal (Noss and Cooperrider 1994). 2. In North America, often refers to those species not present in a bioregion before the entry of Europeans in the 16th century, or present in later parts of that region and later introduced to an ecosystem by human-mediated mechanisms (Cohen and Carlton 1988).


Fauna The animal life of a region or geological period (Allaby 1998)

Fitness Survival and reproduction ability of an individual Wikipedia glossary

Flora Plant or bacterial life forms of a region or geological period (Allaby 1998).

Food chain a group of organisms interrelated by the fact that each member of the group feeds upon on the one below it. Wikipedia glossary

Food web a set of interconnected food chains by which energy and materials circulate within an ecosystem. Wikipedia glossary


Habitat 1. The place, including physical and biotic conditions, where a plant or an animal usually occurs (Allaby 1998). 2. The physical conditions that surround a species, or species population, or assemblage of species, or community (Clements and Shelford, 1939).

Host organism that serves as a habitat for another organism. A host may provide nutrition for a parasite, alternatively with mutualism the host benefits. (from UCMP Understanding Evolution Glossary)


Indigenous A species that occurs naturally in an area; a synonym for native species (Allaby 1998), although see endemic. Wikipedia glossary

Interspecific relations interactions between different species—are numerous, and usually described according to their beneficial, detrimental or neutral effect (for example, mutualism (relation ++) or competition (relation --). The most significant relation is the relation of predation (to eat or to be eaten), which leads to the essential concepts in ecology of food chains (for example, the grass is consumed by the herbivore, itself consumed by a carnivore, itself consumed by a carnivore of larger size). A high predator to prey ratio can have a negative influence on both the predator and prey biocenoses in that low availability of food and high death rate prior to sexual maturity can decrease (or prevent the increase of) populations of each, respectively. Selective hunting of species by humans which leads to population decline is one example of a high predator to prey ratio in action. Other interspecific relations include parasitism, infectious disease and competition for limiting resources, which can occur when two species share the same ecological niche.

Intraspecific relations relations which are established between individuals of the same species, forming a population. They are relations of co-operation or competition, with division of the territory, and sometimes organization in hierarchical societies.


K-selected species species that produce fewer but stronger offspring and dedicate more care to their upbringing. K-selected species are better suited for, and better able to compete with strong competitors in a crowded environment Wikipedia glossary

Keystone species keystone species is a species that has a disproportionate effect on its environment relative to its abundance. Such species affect many other organisms in an ecosystem and help to determine the types and numbers of various others species in a community. Wikipedia glossary


Mimicry imitative behavior, one species resembling one another, and gaining advantages as a result. For example harmless flies that have the same colouration as bees and wasps. Because preditors know that wasps sting they tend to avoid anything that looks like them. Wikipedia glossary

Mutualism A biological interaction between individuals of two different species, where each individual derives a fitness benefit. It includes relationships which are mutualistic, parasitic or commensal.. Wikipedia glossary


Native range The ecosystem that a species inhabits (Booth et al. 2003).

Native species 1. A synonym for indigenous species 2. A species that occurs naturally in an area, and has not been introduced by humans either intentionally or unintentionally (Allaby 2005). 3. In North America, a species established before the year 500 (Jeschke and Strayer 2005)

Naturalized species 1. A species that was originally introduced from a different country, a different bioregion, or a different geographical area, but now behaves like a native species in that it maintains itself without further human intervention and now grows and reproduces in native communities (Allaby 1998). 2. A non native species that forms self-sustaining populations but is not necessarily an invasive species (Booth et al. 2003).

Niche the role the species plays in the functioning of the ecosystem: the "functional status of an organism in its community" (Charles Elton, in Odum, 1959).

Nitrogen cycle a continuous cycle by which nitrogen from the atmosphere and compounded nitrogen keeps getting exhanged through the soil into substances that can be taken up and used by green plants, what is left returns to the air as a result of denitrification. Wikipedia glossary

Nitrogen fixation conversion of nitrogen into nitrogen compounds (ex. nitrate and nitrite) that is carried out naturally by certain bacteria and algae. Wikipedia glossary


Paleoecology the study of the relationships between species in fossil assemblages. More

Population A group of potentially inter-breeding individuals of the same species found in the same place at the same time (Booth et al. 2003).

Population ecology major subfield of ecology that deals with the dynamics of species populations and how these populations interact with the environment. The older term, autecology refers to the roughly same field of study, coming from the division of ecology into autecology—the study of individual species in relation to the environment—and synecology—the study of groups of organisms in relation to the environment—or community ecology. Odum (1959, p. 8) considered that synecology should be divided into population ecology, community ecology, and ecosystem ecology, defining autecology as essentially "species ecology." However, biologists have for some time recognized that the more significant level of organization of a species is a population, because at this level the species gene pool is most coherent. In fact, Odum regarded "autecology" as no longer a "present tendency" in ecology (i.e., an archaic term), although included "species ecology"—studies emphasizing life history and behaviour as adaptations to the environment of individual organisms or species—as one of four sub-divisions of ecology. The development of the field of population ecology owes much to the science of demography and the use of actuarial life tables. Population ecology has also played an important role in the development of the field of conservation biology especially in the development of population viability analysis (PVA) which makes it possible to predict the long-term probability of a species persisting in a given habitat patch (e.g., a national park). While essentially a subfield of biology, population ecology provides many interesting problems for mathematicians and statisticians, which work mainly in the study of population dynamics. wikipedia

Population size a statistic (n) which describes the number of individuals of a species in a particular geographic range. Wikipedia glossary

Predation the interaction among populations when one organism kills and consumes another one. Wikipedia glossary

Prey living organisms that predators feed on.

Primary producer an autotroph that obtains energy directly from the nonliving environment through photosynthesis or less commonly through chemosynthesis. Wikipedia glossary

Primary production production of organic compounds from carbon through photosynthesis. This effects all life on Earth either directly or indirectly. Wikipedia glossary


R-selected species A species that produces a large number of off-spring, each of which receives little care (quantity rather than quality). R-selected species are better suited for variable or unpredictable environments. Wikipedia glossary

Ruderal species A plant associated with human dwellings, construction, or agriculture, that usually colonizes disturbed or waste ground. Ruderals are often weeds which have high demands for nutrients and are intolerant of competition. See also native weed or invasive native (Allaby 1998).


Species A group of organisms formally recognized as distinct from other groups; the taxon rank in the hierarchy of biological classification below that of genus; the basic unit of biological classification, usually defined by the reproductive isolation of the group from all other groups of organisms (Allaby 1998). Evolution glossary. Page


Weed 1. A plant in the wrong place, being one that occurs opportunistically on land or in water that has been disturbed by human activities (see also ruderal species and native weed or invasive native), or on cultivated land, where it competes for nutrients, water, sunlight, or other resources with cultivated plants such as food crops. Under different circumstances the weed plant itself may be cultivated for beneficial purposes (Allaby, 1998). 2. A native or introduced species that has a perceived negative ecological or economic effect on agricultural or natural ecosystems (Booth et al., 2003). 3. A plant growing in an area where it is not wanted (Royer and Dickinson, 1999).


The following refrences are included with A Glossary of Terms Related to Basic Ecology (Ecology - Wikibooks) and don't reflect all the definitions on this page

Allaby, M. 1998. Oxford Dictionary of Ecology. New York, NY: Oxford University Press.

Art, H. W. 1993. The Dictionary of Ecology and Environmental Science. New York, NY: Henry Holt and Company.

Booth, B. D., S. D. Murphy, and C. J. Swanton. 2003. Weed Ecology in Natural and Agricultural Systems. Cambridge, MA: CABI Publishing.

Carlton, J.T. 2001. Introduced Species in U.S. Coastal Waters: Pew Oceans Commissions Report. Pew Oceans Commissions: Washington, DC.

Clements, Frederic E., and Victor E. Shelford. 1939. Bio-ecology. John Wiley & Sons, New York. 425 pp.

Cohen, A. H., and J. T. Carlton. 1998. Accelerating invasion rate in a highly invaded estuary. Science 279: 555-58.

Colautti, R. I., and H. J. MacIsaac. 2004. A neutral terminology to define 'invasive' species. Diversity and Distributions 10: 134-41.

Heutte, T., and E. Bella. 2003. Invasive plants and exotic weeds of Southeast Alaska. Anchorage, AK: USDA Forest Service.

Jeschke, J. M., and D. L. Strayer. 2005. Invasion success of vertebrates in Europe and North America. Proceedings of the National Academy of Sciences 102(20):7198-202.

Noss, R. F., and A. Y. Cooperrider. 1994. Saving Nature's Legacy: Protecting and Restoring Biodiversity. Washington, DC: Island Press.

Odum, E. P. 1959. Fundamentals of ecology. W. B. Saunders Co., Philadelphia and London. 546 p.

Royer, F., and R. Dickinson. 1999. Weeds of the northern U.S. and Canada. Edmonton, AB: Lone Pine Press.

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