Bio307_Lect18_NatureofCommunities_S21 copy

Community

A group of interacting species that inhabit a defined area.

Species richness

The number of different species represented in a community.

Species evenness

The relative abundance of different species in a community.

Species diversity

A measure that combines species richness and species evenness.

Taxonomic affinity

A subset of species defined based on their taxonomic group.

Guilds

Groups of species that use the same resources.

Functional group

Species that share similar functions in the ecosystem but may differ in resources used.

Food web

A complex network of feeding relationships among species in a community.

Trophic levels

Different levels in a food chain that represent the flow of energy and nutrients.

Primary producers

Organisms, such as plants and algae, that produce energy from sunlight.

Primary consumers

Herbivores that consume primary producers.

Secondary consumers

Carnivores that eat primary consumers.

Tertiary consumers

Carnivores that eat secondary consumers.

Species accumulation curves

Graphs that plot species richness against the number of individuals counted.

Keystone species

Species that have a disproportionately large effect on their environment relative to their abundance.

Ecosystem engineers

Species that create, modify, or maintain habitats for themselves and other organisms.

Shannon Index

A common measure of species diversity that accounts for both abundance and evenness of species.

Trophic facilitation

An indirect positive effect on a consumer that occurs due to interactions between different species.

Dominant species

Species that are abundant and have large effects on their community structure.

Direct interactions

Interactions that occur directly between two species, such as predation or competition.

Indirect interactions

Interactions that occur when a relationship between two species is mediated by a third species.