Community Ecology

Flashcards for Community Ecology Lecture Review

Biological Community

An assemblage of populations of various species living close enough for potential interaction.

Interspecific Interactions

Relationships between species in a community, such as competition, predation, herbivory, symbiosis, and facilitation.

Interspecific Competition

A -/- interaction in which species compete for a resource in short supply.

Competitive Exclusion

Local elimination of a competing species due to strong competition.

Ecological Niche

The sum of a species’ use of biotic and abiotic resources in its environment; an organism’s ecological role.

Resource Partitioning

Differentiation of ecological niches, enabling similar species to coexist in a community.

Fundamental Niche

The niche potentially occupied by a species.

Realized Niche

The niche actually occupied by a species, often as a result of competition.

Character Displacement

Tendency for characteristics to be more divergent in sympatric populations than in allopatric populations.

Predation

A +/- interaction in which one species (predator) kills and eats the other (prey).

Herbivory

A +/- interaction in which an herbivore eats parts of a plant or alga.

Symbiosis

A relationship where two or more species live in direct and intimate contact with one another.

Parasitism

A +/- interaction in which one organism (parasite) derives nourishment from another (host), which is harmed.

Mutualism

A +/+ interaction; an interspecific interaction that benefits both species

Commensalism

A +/0 interaction in which one species benefits and the other is neither harmed nor helped.

Facilitation

A +/+ or 0/+ interaction in which one species has positive effects on another species without direct and intimate contact.

Species Diversity

The variety of organisms that make up a community; includes species richness and relative abundance.

Species Richness

The number of different species in a community.

Relative Abundance

The proportion each species represents of all individuals in a community.

Trophic Structure

The feeding relationships between organisms in a community.

Food Chain

A series of steps linking trophic levels from producers to top carnivores.

Food Web

A branching food chain with complex trophic interactions.

Energetic Hypothesis

The concept that the length of a food chain is limited by inefficient energy transfer.

Dominant Species

Species that are the most abundant or have the highest biomass in a community.

Invasive Species

A species, often introduced by humans, that takes hold outside its native range.

Keystone Species

A species that exerts strong control on community structure by their ecological roles or niches.

Bottom-up Model

A model of community organization proposing a unidirectional influence from lower to higher trophic levels.

Top-down Model

Also called the trophic cascade model, proposes that control comes from the trophic level above.

Nonequilibrium Model

Describes communities as constantly changing after being buffeted by disturbances.

Intermediate Disturbance Hypothesis

The concept that moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance.

Ecological Succession

The sequence of community changes after a disturbance.

Primary Succession

Ecological succession that occurs where no soil exists when succession begins.

Secondary Succession

Succession that begins in an area where soil remains after a disturbance.

Evapotranspiration

Evaporation of water from soil plus transpiration of water from plants.

Species-Area Curve

Quantifies the idea that a larger geographic area has more species.

Island Equilibrium Model

Maintains that species richness on an ecological island levels off at a dynamic equilibrium point.

Pathogens

Disease-causing microorganisms, viruses, viroids, and prions.

Zoonotic Pathogens

Pathogens that have been transferred from other animals to humans.