Chapter 41 – Ecological Communities: Vocabulary Review

A comprehensive set of vocabulary flashcards covering key terms from Chapter 41 on Ecological Communities, including species interactions, community structure, disturbance, succession, and disease dynamics.

community ecology

Study of how interactions between species affect community structure and organization.

interspecific interaction

Relationship between individuals of two or more species in a community.

interspecific competition

A –/– interaction in which individuals of different species compete for a limiting resource.

competitive exclusion

Concept that when two similar species compete for the same resources, one will out-compete and eliminate the other.

ecological niche

Sum of a species’ use of biotic and abiotic resources in its environment.

resource partitioning

Division of resources by coexisting species so each differs in one or more niche factors.

character displacement

Greater divergence of traits in sympatric populations than in allopatric ones.

exploitation

+/– interaction in which one species benefits by feeding on and harming another (includes predation, herbivory, parasitism).

predation

Interaction where one species (predator) kills and eats another (prey).

cryptic coloration

Camouflage that makes prey difficult to detect against background.

aposematic coloration

Bright warning colors of animals with effective defenses.

Batesian mimicry

Harmless species resembles a harmful or unpalatable one.

herbivory

+/– interaction in which an organism eats parts of a plant or alga.

parasitism

+/– interaction where parasite benefits by feeding on a host, which is harmed.

parasite

Organism that feeds on the cell contents, tissues, or fluids of a host, usually without killing it.

host

Larger participant in a symbiosis that provides home and food for a smaller symbiont.

endoparasite

Parasite that lives within its host.

ectoparasite

Parasite that feeds on the external surface of its host.

positive interaction

+/+ or +/0 relationship in which at least one species benefits and neither is harmed (mutualism or commensalism).

mutualism

+/+ interaction benefiting individuals of both participating species.

commensalism

+/0 interaction benefiting one species while neither harming nor helping the other.

species diversity

Number of species and their relative abundances in a community.

species richness

Total number of species in a community.

relative abundance

Proportion each species represents of all individuals in a community.

Shannon diversity index (H)

Metric of community diversity: H = – Σ (p ln p) for each species.

biomass

Total mass of organic matter of organisms in a habitat.

introduced species

Species moved by humans to a new region; also called non-native, exotic, or invasive species.

trophic structure

Feeding relationships that govern energy flow and chemical cycling in an ecosystem.

food chain

Pathway along which food energy transfers from one trophic level to the next, beginning with producers.

trophic level

Position an organism occupies in a food chain.

food web

Network of interconnected food chains in an ecosystem.

foundation species

Species that have large effects on community due to size, abundance, or pivotal ecological role, often providing habitat or food.

keystone species

Not necessarily abundant yet exerts strong control on community structure through its ecological role.

ecosystem engineer

Organism that influences community by causing physical changes in the environment.

disturbance

Event, natural or human-caused, that changes a community and removes organisms.

nonequilibrium model

View that communities change constantly after being affected by disturbances.

intermediate disturbance hypothesis

Moderate disturbance levels foster greater species diversity than low or high levels.

ecological succession

Sequential change in species composition following a disturbance.

primary succession

Succession in an area originally lacking organisms and soil.

secondary succession

Succession where a disturbance clears an area but leaves soil intact.

evapotranspiration

Total ecosystem water loss via plant transpiration and landscape evaporation.

species-area curve

Pattern showing that larger geographic areas harbor more species.

pathogens

Organisms or viruses that cause disease.

zoonotic pathogens

Disease agents transmitted to humans from other animals.

vector

Organism that transmits pathogens from one host to another.