An assemblage of populations of various species living close enough for potential interaction
An interaction with another species in a community
The competition by two species for a particular limited resource
The local elimination of one of two or more strongly competing species (-/-)
The sum total of a species' use of the biotic and abiotic resources in its environment
The differentiation of niches that enables similar species to coexist in a community
The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
Occurring in the same or overlapping geographical areas
Occurring in areas isolated geographically from one another
An interaction between species in which one species, the predator, kills and eats the other, the prey. (+/-)
Animals that chew up or digest plant seeds
Camouflage, making prey more difficult to spot
Bright warning coloration possessed by poisonous or otherwise harmful species
Evolution by one species to resemble the coloration body shape or behavior of another species that is protected from predators
Evolution of two species, both of which are unpalatable or lethal, to resemble each other
An interaction in which an animal eats parts of a plant or alga (+/-)
A symbiotic interaction in which one organism, the parasite, derives its nourishment from another, the host, which is harmed in the process (+/-)
An interaction in which two species live together in direct contact
Parasites that live within the skin of a host
Parasites that feed on the outer surface of a host
A type of parasitism in which an insect lays eggs on or in a living host; the larvae then feed on the body of the host, eventually killing it
A disease-causing agent similar to a parasite (+/-)
An interspecific interaction that benefits both species (+/+)
An interaction between species that benefits one of the species but neither harms nor helps the other; for example, "hitchhiking species". (+/0)
A process by which two species evolve in response to changes in each other
The variety of different kinds of organisms in a setting, such as a community
The total number of different species in a community
The proportion each species represents of the total individuals in a community
The feeding relationships between organisms
The transfer of food energy up the trophic levels from its source in plants and other photosynthetic organisms to herbivores, carnivores, and eventually decomposers
A network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem
The length of a food chain is limited by the inefficiency of energy transfer along the chain (supported)
Dynamic Stability Hypothesis
Long food chains are less stable than short chains, and population fluctuations are magnified at higher trophic levels (unsupported)
Those species in a community that are most abundant or have the collective highest biomass
The total mass of all the individuals of a population
Species, generally introduced by humans, that take hold outside of their native range, able to attain environments lacking their natural predators and pathogens.
Species not necessarily abundant in a community, that nevertheless exert strong control on community structure by their pivotal ecological niches
Foundation species that alter the structure or dynamics of the environment so as to have a positive effect on the survival and reproduction of some other species in the community
Postulates an unidirectional influence from lower to higher trophic levels
Postulates that influence moves from predators down to prey
Communities constantly change after being buffeted by disturbances
An event, such as a storm, fire or drought, that changes a community, removes organisms from it, and alters resource availability
Intermediate Disturbance Hypothesis
Suggests that moderate levels of disturbance can create conditions that foster greater species diversity than lower or higher levels of disturbance
A process in which a disturbed area may be colonized by a variety of species,
The colonization of new land that is exposed by avalanches, volcanoes, or glaciers by pioneer organisms
A sequence of community changes that take place after a community is disrupted by natural disasters or human actions
The evaporation of water from soil plus the transpiration of water from plants.
The amount of water annually transpired by plants and evaporated from a landscape, usually measured in millimeters
A combined measure of temperature and sunlight that affects productivity
The biodiversity pattern, first noted by Alexander von Humboldt, that illustrates that the larger the geographic area of a community, the greater the number of species.
The concept, put forth by F. E. Clements, that a community is an assemblage of closely linked species, locked into association by mandatory biotic interactions that cause the community to function as an integrated unit, a sort of superorganism.
The concept, put forth by H. A. Gleason, that a plant community is a chance assemblage of species found in the same area simply because they happen to have similar biotic requirements.
The concept, put forth by Paul and Anne Ehrlich, that many or most of the species in a community are associated tightly with other species in a web of life. according to this model, an increase or decrease in one species in a community affects many other species.
The concept, put forth by Henry Gleason and Brian Walker, that most of the species in a community are not tightly coupled with one another (that is, the web of life is very loose). According to this model, an increase or decrease in one species in a community has little effect on other species, which operate independently.