The energy available to the organism at the third trophic level is called

Options

A. gross primary productivity
B. net primary productivity
C. secondary productivity
D. primary productivity

Answer

To solve the question regarding the energy available to organisms at the third trophic level, we can break down the concepts involved step by step:

### Step-by-Step Solution:

1. **Understanding Trophic Levels**:
- Trophic levels refer to the different levels in a food chain where organisms obtain energy. The first trophic level consists of producers (plants), the second level consists of primary consumers (herbivores), and the third level consists of secondary consumers (carnivores).

2. **Identifying the Trophic Levels**:
- The first trophic level includes producers (e.g., plants).
- The second trophic level includes primary consumers (e.g., herbivores).
- The third trophic level includes secondary consumers (e.g., carnivores).

3. **Defining Productivity**:
- Productivity refers to the rate at which biomass is produced. In the context of ecosystems, we often refer to primary productivity, which is the production of organic compounds by producers.

4. **Types of Primary Productivity**:
- **Gross Primary Productivity (GPP)**: This is the total amount of energy captured by photosynthesis in a given area and time.
- **Net Primary Productivity (NPP)**: This is the energy that remains after the energy used for respiration by producers is subtracted from GPP. NPP is the energy available to primary consumers (herbivores).

5. **Energy Transfer Between Trophic Levels**:
- Generally, about 10% of the energy from one trophic level is transferred to the next level. Thus, the energy available to herbivores (NPP) is what they use to grow and reproduce.

6. **Understanding Secondary Productivity**:
- The energy that is available to the third trophic level (secondary consumers) is derived from the biomass produced by the herbivores, which is referred to as secondary productivity.

7. **Conclusion**:
- The energy available to organisms at the third trophic level is termed **Secondary Productivity**.

### Final Answer:
The energy available to the organism at the third trophic level is called **Secondary Productivity**.

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