6) What is a keystone species? How are keystone species different from dominant species? Provide examples. Why is the starfish, Pisaster, considered a keystone species in many intertidal zones? How might you test whether a species is a keystone?7) What is an ecosystem engineer? How is it different from a keystone species? What is an example of an ecosystem engineer? What is a genetic engineer? Explain why beaver are examples of ecosystem engineers and genetic engineers.8) What is a trophic cascade? What happens if largemouth bass are added to a lake that contains algae, zooplankton, and minnows? Describe how the abundance of each organismincreases or decreases.9) What is biomanipulation? Provide examples of when and why biomanipulation might not go as we planned.