Which is not a structural aspect of ecosystem?

Options

A. Productivity
B. Species composition
C. Diversity
D. Life cycle

Explanation

To determine which option is not a structural aspect of an ecosystem, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of an Ecosystem**:
- An ecosystem is a functional unit of ecology that includes both living (biotic) and non-living (abiotic) components and their interactions.

2. **Identify Structural Aspects of Ecosystems**:
- Structural aspects of an ecosystem refer to the physical and biological components that make up the ecosystem. This includes:
- **Species Composition**: The variety of species present in the ecosystem.
- **Diversity**: The variety of life forms and their abundance in the ecosystem.
- **Life Cycle**: The various stages of development that organisms go through in their life.

3. **Evaluate the Options**:
- Given options are:
1. Productivity
2. Species Composition
3. Diversity
4. Life Cycle

4. **Analyze Each Option**:
- **Productivity**: Refers to the rate at which energy is produced in an ecosystem (e.g., through photosynthesis). It is more related to the functioning of the ecosystem rather than its structure.
- **Species Composition**: A structural aspect as it defines what species are present.
- **Diversity**: A structural aspect as it indicates the variety of species and their distribution.
- **Life Cycle**: A structural aspect as it describes the developmental stages of organisms within the ecosystem.

5. **Conclusion**:
- Based on the analysis, **Productivity** is not a structural aspect of the ecosystem. Therefore, the correct answer is **Option 1: Productivity**.