Worksheet Chapter 9: Ecosystem

1. Explain two ways human activities disrupt natural carbon and nitrogen nutrient cycles in ecosystems.

2. A student uses ten 1 m × 1 m quadrats to estimate the population of dandelion plants in a field. Dandelions were present in 7 quadrats, with a total count of 35 individual plants across all quadrats. Calculate: (a) The percentage frequency of dandelion. (b) The population density of dandelion per m².

3. True or False: Primary succession occurs much faster than secondary succession because soil is already present.

4. Which ecological interaction is demonstrated by tapeworms residing in human intestines?

5. Explain why food chains rarely extend beyond four or five trophic levels.

6. Distinguish between intraspecific competition and interspecific competition, giving one example for each.

7. True or False: In a pyramid of energy, energy increases as you move up from producers to tertiary consumers.

8. State the formula used to estimate population size using the Capture-Mark-Release-Recapture method.

9. Describe the stages of primary succession in a mangrove swamp estuary leading to a terrestrial rainforest climax community.

10. Fill in the blank: The total dry mass of living organic material per unit area at a specific trophic level is referred to as ________.