community
a group of populations of different species living close enough to interact
interspecific interaction
a relationship between individuals of two or more species in a community
interspecific competition
a -/- interaction that occurs when individuals of different species compete for a resource that limits their growth and survival
competitive exclusion
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
ecological niche
the sum of a species' use of the biotic and abiotic resources in its environment
resource partitioning
the differentiation of niches that enables similar species to coexist in a community
predation
a +/- interaction between species in which one species kills and eats the other
cryptic coloration
camouflage such that a potential prey is difficult to spot against its background
aposematic coloration
the bright colors of animals with effective physical or chemical defenses that acts as a warning to predators
Batesian mimicry
a palatable or harmless species mimics an unpalatable or harmful model
Mullerian mimicry
two or more unpalatable species resemble each other
herbivory
a +/- interaction in which an organism eats parts of a plant or alga
symbiosis
a relationship where individuals of two or more species live in direct and intimate contact with one another
parasitism
a +/- symbiotic interaction in which one organism derives its nourishment from another organism which is harmed in the process
parasite
an organism that feeds on the cell contents, tissues, or body fluids of another species while in or on the host organism; often harm but usually do not kill their host
host
the larger participant in a symbiotic relationship, serving as home and food source for the smaller symbiont
endoparasite
an organism that lives within its host
ectoparasite
an organism that feeds on the external surface of a host
mutualism
a +/+ symbiotic interaction that benefits both species
commensalism
a +/0 symbiotic interaction between species that benefits one of the species but neither harms nor helps the other
species diversity
the variety of different kinds of organisms that make up the community
species richness
the number of different species in the community
relative abundance
the proportion each species represents of all individuals in the community
trophic structure
the different feeding relationships in an ecosystem, which determine the route of energy flow and the pattern of chemical cycling
food chain
the pathway along which food energy is transferred from trophic level to trophic level, beginning with producers
food web
the interconnected feeding relationships in an ecosystem
energetic hypothesis
the concept that the length of a food chain is limited by the inefficiency of energy transfer along the chain
biomass
the total amount of organic matter comprising a group of organisms in a particular habitat
dynamic stability hypothesis
the idea that long food chains are less stable than short chains
dominant species
a species with substantially higher abundance than other species in a community, exerting a powerful control over the occurrence and distribution of other species
invasive species
a species, often introduced by humans, that takes hold outside its native range
keystone species
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