Community Ecology

What distinguishes a biological community from an ecosystem?

A biological community is a group of interacting species in a specific area, while an ecosystem includes both the community and its abiotic environment.

What is intraspecific interaction?

Interaction that occurs among individuals of the same species.

What is interspecific interaction?

Interaction between organisms of different species.

Define competition in terms of interspecific interactions.

Both species involved are harmed.

What is exploitation in interspecific interactions?

One species is positively affected, while the other is negatively affected.

What is predation?

An interaction between species in which one species, the predator, eats the other, the prey.

What is herbivory?

An interaction where an organism eats plants or algae.

Define parasitism.

Occurs when one organism lives in another organism and negatively affects the organism it is living on.

What is mutualism?

An interaction where both species benefit.

Define commensalism.

A +/0 interaction where one organism benefits and the other is neither helped nor harmed.

What is competitive exclusion?

When one species uses resources more efficiently and eventually eliminates the other population.

What is resource partitioning?

The division of environmental resources by coexisting species in a niche.

What is character displacement?

When an organism's behavioral and physical traits change to coexist with another species.

Define niche.

The role of a species in how an organism obtains its food, water, etc.

What is a realized niche?

The niche that is restricted when competition is present, smaller than the fundamental niche.

What is a fundamental niche?

The niche determined by abiotic resources.

What is species diversity?

The number and relative abundance of species in a biological community.

Define species evenness.

A measure of how evenly species are distributed in a community.

What is species richness?

The number of species in a biological community.

What are dominant species?

Species that are very abundant, usually producers, and have lots of biomass.

Define keystone species.

Species that have less biomass, typically consumers, and exert top-down control.

What is the difference between top-down and bottom-up control in community organization?

Top-down is controlled by consumers/keystone species, while bottom-up is controlled by dominant/producers.

Describe primary succession.

Starting from scratch in a new area with no soil or rock.

What is secondary succession?

When life recovers after a disturbance, and soil already exists in the environment.