Unit 2: Part 4

Scientists observe that wolves in Yellowstone control elk populations, allowing young trees to grow. What concept does this best illustrate?

• Mutualism

• Energy pyramid

• Trophic cascade

• Commensalism

After sea stars were removed from a tide pool ecosystem, mussels took over and biodiversity decreased. What does this tell you about sea stars?

• They are decomposers

• They are producers

• They are a keystone species

• They are herbivores

A student notices hawks and owls hunt similar prey. At night, owls are more successful. What ecological concept is demonstrated here?

• Predation

• Mutualism

• Niche partitioning

• Trophic cascade

A scientist creates an energy pyramid. Only 10% of energy from plants is passed to deer. What happens to the other 90%?

• Stored in fat

• Lost as heat or used for life processes

• Used in photosynthesis

• Turned into waste only

In a coral reef, a small fish eats parasites off larger fish. Which relationship is best shown?

• Parasitism

• Commensalism

• Mutualism

• Competition

If a new disease kills off the grass population in a prairie, what would happen to the rest of the food web?

• Herbivores increase

• All populations increase

• Collapse of higher trophic levels due to energy loss

• Carnivores will become producers

A biologist removes all coyotes from a desert ecosystem. What might be a logical effect?

• Plants increase rapidly

• Nothing changes

• Rise in small herbivores, decline in plants

• More water becomes available

Why do energy pyramids typically have no more than four or five trophic levels?

• Lack of space

• Too much competition

• Energy decreases at each level, limiting sustainability

• Producers are outcompeted

Which relationship is best modeled by this scenario: A remora fish rides on a shark and eats leftover scraps, but the shark is unaffected.

• Parasitism

• Mutualism

• Commensalism

When wolves were reintroduced to Yellowstone National Park, the behavior of the deer population changed, leading to the regrowth of certain vegetation areas. This series of events demonstrates a trophic cascade. What is the primary reason for the vegetation regrowth in Yellowstone following the reintroduction of wolves?

• Wolves provided additional nutrients to the soil through their waste, which promoted vegetation growth.

• The deer population decreased due to predation by wolves, reducing overgrazing and allowing vegetation to recover.

• Wolves directly planted new vegetation as part of their territorial marking behaviors.

• The presence of wolves led to an increase in the number of plant species that deer do not eat, which outcompeted other vegetation.