Unit 3: Functioning Ecosystems. 5

What is a keystone species?

• A species that is the most abundant in an ecosystem

• A species that has a unique and crucial role in maintaining the structure of a community

• A species that is the largest in an ecosystem

• A species that is the fastest in an ecosystem

Which of the following is NOT a category of keystone species?

• Producers

• Predators

• Ecosystem engineers

• Mutualists

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

• Flowers

• Beavers

• Sharks

• Bees

What role do ecosystem engineers play in an ecosystem?

• They disperse seeds

• They control prey numbers

• They create, destroy, or change an ecosystem

• They interact for mutual benefit

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

• Cassowaries

• Bees

• Beavers

• Sharks

What is the main food of the Southern Cassowary?

• Insects

• Rainforest fruits

• Fish

• Small mammals

How does the Southern Cassowary help in seed dispersal?

• By eating seeds and excreting them unharmed

• By burying seeds in the ground

• By carrying seeds on its fur

• By dropping seeds from trees

What is a key feature of a keystone species?

• It is the fastest species in the ecosystem

• It is the largest species in the ecosystem

• Its influence on other organisms is out of proportion to its biomass or abundance

• It is the most abundant species in the ecosystem

What happens if a keystone species is removed from an ecosystem?

• New species immediately take its place

• The ecosystem may collapse or become unbalanced

• The ecosystem becomes more diverse

• Nothing changes

Which of the following is NOT a role of a keystone species?

• Controlling prey numbers

• Creating new ecosystems

• Maintaining the balance of organisms

• Interacting for mutual benefit