The bright coloration of animals with effective physical or chemical defenses that acts as a warning to predators.
A type of mimicry in which a harmless species looks like a species that is poisonous or otherwise harmful to predators.
A technique for restoring eutrophic lakes that reduces populations of algae by manipulating the higher-level consumers in the community rather than by changing nutrient levels or adding chemical treatments.
The dry weight of organic matter comprising a group of organisms in a particular habitat.
A model of community organization in which mineral nutrients control community organization because nutrients control plant numbers, which in turn control herbivore numbers, which in turn control predator numbers.
The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
The mutual evolutionary influence between two different species interacting with each other and reciprocally influencing each other's adaptations.
A symbiotic relationship in which the symbiont benefits but the host is neither helped nor harmed.
All the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction.
The concept that when populations of two similar species compete for the same limited resources, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other population.
Camouflage, making potential prey difficult to spot against its background.
A force that changes a biological community and usually removes organisms from it. Disturbances, such as fire and storms, play pivotal roles in structuring many biological communities.
Those species in a community that have the highest abundance or highest biomass. These species exert a powerful control over the occurrence and distribution of other species.
dynamic stability hypothesis
The idea that long food chains are less stable than short chains.
The sum total of a species' use of the biotic and abiotic resources in its environment.
Transition in the species composition of a biological community, often following ecological disturbance of the community; the establishment of a biological community in an area virtually barren of life.
A parasite that feeds on the external surface of a host.
A parasite that lives within a host.
The concept that the length of a food chain is limited by the inefficiency of energy transfer along the chain.
The evaporation of water from soil plus the transpiration of water from plants.
A species that has a positive effect on the survival and reproduction of other species in a community and that contributes to community structure.
The pathway along which food is transferred from trophic level to trophic level, beginning with producers.
The elaborate, interconnected feeding relationships in an ecosystem.
An interaction in which an herbivore eats parts of a plant or alga.
The larger participant in a symbiotic relationship, serving as home and feeding ground to the symbiont.
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 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.
intermediate disturbance hypothesis
The concept that moderate levels of disturbance can foster greater species diversity than low or high levels of disturbance.
Relationships between species of a community.
Competition for resources between plants, between animals, or between decomposers when resources are in short supply.
A species that is not necessarily abundant in a community yet exerts strong control on community structure by the nature of its ecological role or niche.
A mutual mimicry by two unpalatable species.
A symbiotic relationship in which both participants benefit.
The model of communities that emphasizes that they are not stable in time but constantly changing after being buffeted by disturbances.
An organism that absorbs nutrients from the body fluids of living hosts.
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.
An interaction between species in which one species, the predator, eats the other, the prey.
A type of ecological succession that occurs in a virtually lifeless area, where there were originally no organisms and where soil has not yet formed.
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.
Differences in the abundance of different species within a community.
The division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species.
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.
A type of succession that occurs where an existing community has been cleared by some disturbance that leaves the soil intact.
The number and relative abundance of species in a biological community.
The number of species in a biological community.
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.
A model of community organization in which predation controls community organization because predators control herbivores, which in turn control plants, which in turn control nutrient levels; also called the trophic cascade model.
The different feeding relationships in an ecosystem, which determine the route of energy flow and the pattern of chemical cycling.