Question

Two main structural features of an ecosystem are:

• A. Species composition and stratification
• B. Species composition and productivity
• C. Productivity and energy flow
• D. Nutrient cycling and stratification

Answer 1

The correct option is A:

Explanation of the correct answer:

1. Ecosystem is the major ecological unit.
2. It has both structure and functions.
3. The structure is related to species diversity and stratification.
4. Species Diversity is simply the number and relative abundance of species found in a given biological organisation.
5. Stratification is the vertical distribution of different species occupying different levels. For e.g., tree occupy top vertical strata or layer of a forest, shrubs the second and herbs and grasses occupy the bottom layers.

Explanation of the incorrect answers:

Option B:

1. Productivity of the ecosystem and energy flow in the ecosystem are the functional aspects of the ecosystem.
2. These are not structural aspects.

Option C:

1. Ecosystem contains four functional aspects for its maintenance.
2. These are biogeochemical cycles, energy flow, nutrient cycle, and productivity.
3. Hence, nutrient cycling is also the functional aspect of the ecosystem.

Option D:

1. Productivity is the functional aspect of the ecosystem.
2. Hence, this option is not correct.

Final answer: Two main structural features of an ecosystem are species composition and stratification.