AP Biology community interactions study guide

What is mutualism?

An interaction where both species benefit, e.g., bees and flowers.

Example of commensalism

Barnacles on whales; barnacles benefit, whales are unaffected.

Difference between predation and parasitism

Predation benefits one, harms the other. Parasitism benefits one, harms the other but typically does not kill.

Fill in the blank: __________ is the competition for resources between species.

Interspecific competition.

True or false: Intraspecific competition occurs between different species.

False, because it occurs within the same species.

What is the competitive exclusion principle?

Two species competing for the same resources cannot coexist indefinitely.

What is an ecological niche?

The role and space an organism occupies in its environment.

Difference between fundamental and realized niche

Fundamental niche is the potential range; realized niche is the actual range due to competition.

What is resource partitioning?

When species divide resources to reduce competition.

True or false: Keystone species have a disproportionately large effect on their environment.

True, because they maintain the structure of the ecosystem.

Examples of keystone species

- Sea otters - Wolves - Beavers

What is primary succession?

Ecological succession that starts on bare rock, e.g., after a volcanic eruption.

What is secondary succession?

Succession that occurs after a disturbance that leaves the soil intact, e.g., after a forest fire.

Define trophic levels.

The levels in a food chain, including producers, primary consumers, secondary consumers, and tertiary consumers.

What is a food web?

A complex network of feeding relationships among organisms in an ecosystem.

What role do decomposers play?

They break down dead organisms, recycling nutrients back into the ecosystem.

What is the difference between an autotroph and a heterotroph?

Autotrophs produce their own food; heterotrophs consume other organisms.

Example of a biotic factor

Plants, animals, fungi, and bacteria are all biotic factors in an ecosystem.

Example of an abiotic factor

Sunlight, temperature, soil, and water are abiotic factors.

What is a niche differentiation?

The process by which competing species evolve to utilize different resources.

Define symbiosis.

A close and long-term interaction between two different biological species.

What is a population?

A group of individuals of the same species living in a specific area.

Fill in the blank: __________ is the maximum population size that an environment can sustain.

Carrying capacity.

Define ecological footprint.

The impact of a person or community on the environment, expressed as the amount of land required.

What is an invasive species?

A non-native species that spreads widely and causes harm to native ecosystems.

What is biomagnification?

The increasing concentration of toxins in organisms at each successive trophic level.