[Campbell Biology P.718] Lichens are described as "important pioneers" on cleared rock and s... | Practice Question

Lichens are described as "important pioneers" on cleared rock and soil surfaces. Which of the following best explains their pioneering role in ecological succession, according to the text?

  • A: They act as primary producers, directly consumed by higher trophic levels, thus initiating a food web.
  • B: They secrete acids to break down rock and trap windblown soil, which creates conditions for plant growth.
  • C: They primarily serve as a food source for herbivores in harsh environments, making them suitable for subsequent colonization.
  • D: They fix atmospheric nitrogen, but this fixed nitrogen is only accessible to the fungal partner, not other plants.

Explanation

The text explicitly states: 'They break down the surface by physically penetrating and chemically attacking it, and they trap windblown soil. ...These processes make it possible for a succession of plants to grow.' This directly describes their pioneering role in creating suitable conditions for other plant life.