Ecosystem Relationships and Keystone Species

The video tutorial covers symbiosis, a close and permanent relationship between two organisms, and its three types: commensalism, mutualism, and parasitism. Commensalism involves one organism benefiting while the other is unaffected. Mutualism benefits both organisms, while parasitism benefits one and harms the other. The video also discusses keystone species, which are crucial for maintaining ecosystem balance. Removing keystone species can lead to ecosystem collapse.

What is the primary requirement for a relationship to be considered symbiotic?

• The relationship must be close and permanent.

• Both organisms must benefit equally.

• The relationship must be temporary.

• Both organisms must be of the same species.

In a commensal relationship, what happens to the organism that is not benefiting?

• It dies.

• It is unaffected.

• It is harmed.

• It benefits equally.

Which of the following is an example of commensalism?

• A tick feeding on a dog.

• A remora fish riding on a shark.

• A lion hunting a zebra.

• A bee pollinating a flower.

What is the main characteristic of mutualism?

• Both species are unaffected.

• One species is unaffected.

• Both species benefit.

• One species benefits while the other is harmed.

Which of the following pairs is an example of mutualism?

• A shark and a remora fish.

• A lion and a gazelle.

• A cleaner fish and a moray eel.

• A flea on a dog.

In parasitism, what typically happens to the host organism?

• It benefits from the relationship.

• It is unaffected.

• It dies immediately.

• It is harmed but not killed.

Which of the following is a common example of parasitism?

• A tick feeding on a mammal.

• A lion hunting a zebra.

• A bee pollinating a flower.

• A remora fish riding on a shark.

What role do keystone species play in an ecosystem?

• They are critical for maintaining ecosystem balance.

• They have no significant impact.

• They are the least important species.

• They are the most numerous species.

What can happen to an ecosystem if a keystone species is removed?

• New species immediately take over.

• The ecosystem collapses.

• Nothing changes.

• The ecosystem becomes more stable.

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

• A sea otter.

• A house cat.

• A garden snail.

• A domestic dog.