The rate of production of organic matter of an ecosystem during photosynthesis is

Options

A. Net primary productivity
B. Gross primary productivity
C. Primary productivity
D. Secondary productivity

Answer

To solve the question regarding the rate of production of organic matter in an ecosystem during photosynthesis, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding Ecosystem Productivity**:
- An ecosystem is a functional unit of nature where various organisms interact with each other and their environment. One of the key characteristics of an ecosystem is its productivity, which refers to the rate at which organic matter is produced.

2. **Defining Productivity**:
- Productivity in an ecosystem can be measured in terms of weight (mass of organic matter) or energy (energy captured through photosynthesis).

3. **Identifying Types of Productivity**:
- **Gross Primary Productivity (GPP)**: This is the total amount of organic matter produced by autotrophs (producers) in an ecosystem through photosynthesis.
- **Net Primary Productivity (NPP)**: This is the amount of organic matter that remains after autotrophs have used some of the GPP for their own respiration. It represents the energy available for consumption by herbivores and other organisms.
- **Primary Productivity**: This is a general term that encompasses both GPP and NPP.
- **Secondary Productivity**: This refers to the generation of biomass by heterotrophic organisms (consumers) that eat the organic matter produced by autotrophs.

4. **Focusing on Photosynthesis**:
- The question specifically asks about the rate of production of organic matter during photosynthesis. Since we are interested in the total organic matter produced by autotrophs through photosynthesis, we need to focus on Gross Primary Productivity.

5. **Choosing the Correct Answer**:
- Based on the definitions and the context of the question, the correct answer is **option B: Gross Primary Productivity**. This is because it directly relates to the total organic matter produced during the process of photosynthesis.

### Final Answer:
The rate of production of organic matter of an ecosystem during photosynthesis is **Gross Primary Productivity (option B)**.

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