The rate of conversion of light energy into chemical energy of organic molecules in an ecosystem is

Options

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

Answer

To solve the question regarding the rate of conversion of light energy into chemical energy of organic molecules in an ecosystem, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept**:
- The question asks about the conversion of light energy into chemical energy. This process primarily occurs in plants through photosynthesis.

2. **Identifying the Process**:
- During photosynthesis, plants use sunlight to convert carbon dioxide and water into glucose and oxygen. The glucose represents the chemical energy stored in organic molecules.

3. **Defining Productivity**:
- The term "productivity" in ecology refers to the rate at which energy is converted into organic substances. In this context, it specifically refers to how efficiently plants convert light energy into chemical energy.

4. **Types of Productivity**:
- There are two main types of primary productivity:
- **Gross Primary Productivity (GPP)**: This is the total amount of light energy converted into chemical energy by plants in a given area over a specific time period.
- **Net Primary Productivity (NPP)**: This is the amount of chemical energy stored in the plant biomass after accounting for the energy used in respiration by the plants.

5. **Determining the Correct Term**:
- Since the question specifically asks for the rate of conversion of light energy into chemical energy, we focus on the total conversion, which is represented by Gross Primary Productivity (GPP).

6. **Conclusion**:
- Therefore, the rate of conversion of light energy into chemical energy of organic molecules in an ecosystem is called **Gross Primary Productivity (GPP)**.

### Final Answer:
The rate of conversion of light energy into chemical energy of organic molecules in an ecosystem is called **Gross Primary Productivity (GPP)**.