EcologyLesson 3 of 5 in the course Succession and disturbance

Keystone Species: Predation, Mutualism, and Ecosystem Engineering

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

This lesson introduces what makes a species a keystone, how the concept was developed, and why a species’ ecological influence cannot be judged by its abundance alone.

A keystone species has a disproportionately large effect on its natural environment relative to its abundance. It can influence the structure of an ecological community by affecting the populations of many other organisms and helping determine which species live there and in what numbers.

All flashcards

What is a keystone species?
A species with an ecological effect that is disproportionately large relative to its abundance, helping shape the structure of its community.
Who introduced the keystone species concept?
Zoologist Robert T. Paine introduced the concept in 1969, drawing on research into intertidal marine communities.
What did Paine’s sea star removal experiment show?
Without ochre sea stars, mussels expanded across the rocks and crowded out many other species, showing that a predator could help maintain community diversity.
Why is a keystone in an arch an analogy for a keystone species?
A relatively small part can support a larger structure, which may collapse if that part is removed.
How does a keystone species differ from a flagship species?
A keystone species is defined by its unusually large ecological effect. A flagship species is defined by its ability to attract public interest and conservation support.

Quiz questions

  1. What is a trophic cascade?Answer: A chain of effects that spreads through feeding relationships.
  2. Why can a sea star be a keystone predator even though it is not an apex predator?Answer: It can regulate mussels even though other animals prey on it.
  3. How can acorn banksia support pollination in Western Australia’s Avon Wheatbelt?Answer: Its nectar supports honeyeaters that pollinate many plant species.
  4. What makes an organism an ecosystem engineer?Answer: It changes the physical environment in ways that affect other species.
  5. What did Bruce Menge observe about the role of Paine’s purple sea star?Answer: It had a stronger keystone effect in wave-exposed areas than in sheltered places.

Based on the Wikipedia article Keystone species, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

More in Ecology

All Ecology lessons
EcologyEnvironmental Controls on Species Distributions and Ecosystem Processes5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPrimary Production: Ecosystem Controls, Measurement, and Human Impacts5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPredation: Foraging, Adaptations, and Ecosystem Effects5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPopulation Growth, Regulation, and Life-History Strategies5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyBiogeochemical Cycles of Water, Carbon, Nitrogen, Phosphorus, and Sulfur5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPopulation Regulation and K–r Life-History Strategies5 flashcards · 5 quiz questions · 4 gamesPlay free →