Environmental Science- Chapter Four Vocabulary

Abundance

The number or amount of something

Batesian mimicry

Evolution by one species to resemble the coloration, body shape, or behavior of another species that is protected from predators by a venomous bad taste, stinger, or some other defense adaptation

Climax community

A relatively stable, long-lasting community reached in a successional series; usually determined by climate and soil type

Coevolution

The process in which species exert selective pressure on each other and gradually evolve new features or behaviors as a result of those pressures

Commensalism

A symbiotic relationship in which one member is benefited and the other is neither harmed nor benefited

Complexity

The number of species at each trophic level and the number of trophic levels in a community

Diversity

The number of species present in a community (species richness), as well as the relative abundance of each species.

Ecological development

A gradual process of environmental modification by organisms

Ecological niche

The functional role and position of a species (population) within a community (ecosystem), including what resources it uses, how and when it uses the resources, and how it interacts with other populations

Ecotone

A boundary between two types of ecological communities

Edge effects

A change in species composition, physical conditions, or other ecological factors at the boundary between two ecosystems

Environmental Indicators

Organisms or physical factors that serve as a gauge for environmental changes. Specifically, organisms with these characteristics are called bioindicators.

Equilibrium communities/Disclimax community

A community subject to period disruptions, usually by fire, that prevent it from reaching a climax stage

Evolution

A theory that explains how random changes in genetic material and competition for scarce resources cause species to gradually change

Fire climax community

An equilibrium community maintained by periodic fires; examples include grasslands, chapparal shrubland, and some pine forest.

Habitat

The place or set of environmental conditions in which a particular animal lives

Interspecific competition

In a community, competition for resources between members of DIFFERENT species

Intraspecific competition

In a community, competition for resources among members of the SAME species

Keystone species

A species whose impacts on its community or ecosystem are much larger and more influential than would be expected from mere existence

Mullerian mimicry

Evolution of two species, both of which are unpalatable and have poisonous stingers or some of defense mechanism, to resemble each other

Mutualism

A symbolic relationship between individuals of two different species in which both species benefit from the association

Natural selection

The mechanism of evolutionary change in which environmental pressures cause certain genetic combinations in a population to become more abundant. Genetic combinations best adapted for present environmental conditions tend to become predominant.

Parasites

Organisms that live on or in another organism, deriving nourishment at the expense of it's host, usually without killing it.

Patchiness

Within a larger ecosystem, the presence of smaller areas that differ in some physical conditions and thus support somewhat different communities; adversity promoting phenomenom.

Pathogens

Organism that produce disease in a host organism, disease being an alteration of one or more metabolic functions in response to the presence of the organism

Pioneer species

In primary succession on a terrestrial site, the plants, lichens, and microbes that first colonize the site.

Plankton

Primarily microscopic organisms that occupy the upper water layers in both fresh water and marine ecosystems

Predator

An organism that feeds directly on other organisms in order to survive; live-feeders, such as herbivores and carnivores

Primary productivity

Synthesis of organic materials (biomass) by green plants using the energy captured in photosynthesis

Primary succession

An ecological succession that begins in an area where no biotic community previously existed

Resource Partitioning

In a biological community, various populations sharing environmental resources through specialization, thereby reducing direct competition

Secondary succession

Succession on a site where an existing community has been disrupted

Structure

Patterns of organization, both spatial and functional , in a community

Symbiosis

The intimate living together of members of two different species, includes mutualism, commensalism, and, sometimes, parasitism.

Territoriality

The intense form of intraspecific competition in which organisms define an area surrounding their homesite or nesting site and defend it, primarily against other members of their own species

Tolerance limits

Chemical or physical factors that limit the existence, growth, abundance, or distribution of an organisms