BIOL1104 Communities and Ecosystems

Community

an assemblage of populations of different species interacting with one another within the same environment.

species richness

number of various species in the community

species diversity

includes both species richness and the relative abundance of the different species

Population

A group of individuals that belong to the same species and live in the same area

Abiotic components of an ecosystem

-nutrients

-water

-solar energy

-air

Biotic components of an ecosystem

communities of living organisms in a given area

Autotrophs

Organisms that make their own food

Producer

autotrophs; they produce food from inorganic nutrients.

Consumers

consume food generated by a producer:

herbivores, carnivores, omnivores, decomposers, detritivores

herbivores

Feed on plants and algae

Detritovores

Organisms that feed on detritus

decomposers

Feed on decomposing organic matter

Carnivores

Feed on other animals

Energy flow

The passage of energy through the components of an ecosystem

Food chain

diagram showing a single path of energy flow in an ecosystem.

trophic level

Each step in a food chain or food web

food web

Represents interconnecting paths of energy flow within ecosystems

Describes trophic (feeding) relationships

ecological pyramid

illustration of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web

abiotic reservoir

where a chemical accumulates or is stockpiled outside of living organisms

biogeochemcial cycle

the exchange of matter through the biosphere

Coevolution

Process by which two species evolve in response to changes in each other

ecological niche

A specific role of a species within an ecosystem, including its use of resources, and relationships with other species.

Ecosystem

A community of organisms and their abiotic environment

interspecific competition

competition between different species

keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

Mutualism

both organisms benefit

Predation

the preying of one animal on others.

Commensalism

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

Parasitism

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

relative abundance (evenness)

the proportion each species represents of all individuals in the community