Keystone Species and Trophic Cascades

What was the primary question the ecologists sought to answer with his starfish experiment?

• How do predators influence the structure of ecosystems?

• How do starfish reproduce?

• What determines the population size of starfish?

• What was the apex predator in the ecosystem?

Tags

NGSS.HS-LS2-6

NGSS.HS-LS4-5

The original hypothesis of food chains was

• the green hypothesis

• the bottom up hypothesis

• energy flow hypothesis

• Keystone hypothesis

What was the unexpected result of removing starfish from the ecosystem?

• starfish population increased

• number of species decreased

• the ecosystem was unchanged

• number of species increased

Tags

NGSS.HS-LS2-6

NGSS.HS-LS4-5

What term did Robert Paine coin to describe the influence of a single species on an ecosystem?

• Apex predator

• Dominant species

• Keystone species

• Primary species

Tags

NGSS.HS-LS4-5

What was the main finding of the ecologists research on sea otters?

• Sea otters are primary producers

• Sea otters have little to no impact on the ecosystem

• Sea otters indirectly controlled the sea urchins

• Sea otters directly controlled the sea urchins

Tags

NGSS.HS-LS2-6

What happened to the kelp forest when the sea otters were removed?

• Kelp forests became more diverse

• Kelp forests disappeared

• Kelp forests thrived

• Kelp forests were unchanged

Tags

NGSS.HS-LS2-6

What do ecologists call the effect of one species affecting multiple levels in a food chain?

• direct

• indirect

• no effect

• neutral effect

Tags

NGSS.HS-LS2-6

What did ecologists call the effect of one species on multiple levels of a food chain?

• Trophic cascade

• Food chain reaction

• direct effect

• Keystone effect

Tags

NGSS.HS-LS2-6

What broader implication does the study of keystone species and trophic cascades have for ecology?

• It indicates that predators have no significant role in ecosystems

• It shows that all species have equal impact on ecosystems

• It highlights the importance of top down regulation in ecosystems

• It suggests that ecosystems are primarily controlled by the producers

Tags

NGSS.HS-LS2-6

NGSS.HS-LS4-5

What is the role of keystone species in an ecosystem?

• They have no effect on the ecosystem

• They have a disproportionately large effect on the abundance and number of species

• They are the most abundant species

• They are always apex predators.

Tags

NGSS.HS-LS4-5