Keystone

What is a keystone species?

• A species that is most abundant in an ecosystem.

• A species that plays a critical role in maintaining the structure of an ecological community.

• A species that has no predators in its ecosystem.

• A species that can live in a variety of ecosystems.

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Which of the following is an example of a keystone species?

• Cattle

• Sea otter

• Grass

• Mosquito

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How can the removal of a keystone species affect an ecosystem?

• It can increase biodiversity.

• It can lead to a more stable ecosystem.

• It can cause a trophic cascade and disrupt the ecosystem balance.

• It has no significant effect.

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Why are keystone species important for biodiversity?

• They are the most numerous species in their ecosystems.

• They provide food for all other species.

• They help to maintain the structure and integrity of the ecosystem.

• They have no predators, ensuring their survival.

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What could be a direct consequence of removing a top predator from an ecosystem?

• A decrease in the population of primary consumers.

• An increase in the diversity of plant species.

• A decrease in the overall biodiversity of the ecosystem.

• An increase in the population of herbivores, leading to overgrazing.

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A species that plays a critical role in the health, maintenance, growth, or definition of an ecosystem.

• keystone

• invasive

• engineer

• predator

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Which one of the following keystone examples is a keystone predator found in the tidal pools of northwestern North America and was the species that launched Robert Paine’s keystone species concept?

• starfish

• sea otters

• beavers

• wolves

• elephants

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Based on the graph shown, how can you tell sea otters are a keystone species?

• as the sea otter population decreases, biodiversity increases

• as sea otter population increases, biodiversity increases

• changes in the sea otter population have little effect on biodiversity 

• the sea otter population dereases due to the presence of urchins

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Why are bees considered a keystone species?

• The honey they make supports the bear population

• They pollinate flowers that produce fruit which supports the ecosystem

• They sting when threatened

• They live in hives

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Why are some sharks considered a keystone species?

• Because they are a top predator

• They scare off smaller fish that may overgraze an area of sea grass

• They are tertiary consumers

• They are cartilaginous

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