Community Ecology

niche

An organism's particular role in an ecosystem, or how it makes its living.

tolerance

ability of an organism to survive and reproduce under changing environmental conditions

resource partitioning

the differentiation of niches that enables similar species to coexist in a community

predation

An interaction in which one organism captures and feeds on another organism

parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

symbiosis

A close relationship between two species that benefits at least one of the species.

herbivory

interaction in which one animal (the herbivore) feeds on producers (such as plants)

mutualism

A relationship between two species in which both species benefit

commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

competition

the struggle between organisms to survive in a habitat with limited resources

intraspecific competition

competition between members of the same species

interspecific competition

competition between members of different species

abiotic factor

physical, or nonliving, factor that shapes an ecosystem

biotic factor

A living part of an ecosystem

ecosystem

A biological community of interacting organisms and their physical environment.

autotroph

An organism that makes its own food

producers

Organisms that make their own food

photosynthesis

process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

chemosynthesis

process in which chemical energy is used to produce carbohydrates

primary consumers

animals that feed on producers; ex. herbivores

secondary consumers

carnivores that eat herbivores

tertiary consumers

carnivores that eat other carnivores

trophic levels

levels of nourishment in a food chain

decomposer

organism that breaks down and obtains energy from dead organic matter

energy pyramid

A diagram that shows the amount of energy that moves from one feeding level to another in a food web

food chain

series of steps in an ecosystem in which organisms transfer energy by eating and being eaten

food web

a system of interlocking and interdependent food chains.

apex predator

the top predator in an ecosystem

carnivore

organism that obtains energy by eating animals

omnivore

organism that obtains energy by eating both plants and animals

scavenger

an organisms that feeds on the bodies of dead organisms

herbivore

organism that obtains energy by eating only plants

heterotroph

an organism that cannot make its own food

keystone species

a species that influences the survival of many other species in an ecosystem

succession

A series of predictable and orderly changes within an ecosystem over time.

primary succession

An ecological succession that begins in an area where no biotic community previously existed (starting from rock)

secondary succession

reestablishment of a damaged ecosystem in an area where the soil was left intact

pioneer species

first species to populate an area during succession

climax communities

a stable community that completes the succession process

species diversity

Variety of different kinds of organisms that make up a community.

disturbance

an event, caused by physical, chemical, or biological agents, resulting in changes in population size or community composition

detritivore

organism that feeds on plant and animal remains and other dead matter

10% rule

the amount of energy transferred between trophic levels moving up the energy pyramid.

lichen

pioneer species in primary succession

sun

source of energy for the planet