Changes in ecosystems Quiz
Studying this course? Keep your progress in one place.
Pick an answer for each. Quizzes never use energy.
5 questions, one answer each
Each answer is checked as you go, with why.
See all 5 questions
1. Which statement describes secondary succession?
- A. It begins on bare rock
- B. It begins where soil is already present
- C. It always ends in a plagioclimax
- D. It never involves pioneer species
2. A frost kills 40% of a population regardless of its size. This is a
- A. density-dependent biotic factor
- B. density-independent abiotic factor
- C. density-independent biotic factor
- D. density-dependent abiotic factor
3. Why does grazing maintain a plagioclimax?
- A. It adds nutrients so trees grow faster
- B. It stops the climate changing
- C. It prevents woody species establishing
- D. It speeds succession to the climatic climax
4. How do pioneer species help later colonisers?
- A. They decompose to form soil that retains water and nutrients
- B. They prevent any competition
- C. They remove all light
- D. They lower the temperature of the bedrock
5. In a field investigation, random sampling is used to
- A. save time
- B. make sure the sites have the same abiotic conditions
- C. avoid bias in the choice of sample positions
- D. increase the carrying capacity