The species composition that invades a barren area and drives the succession is called

Options

A. a climax community
B. a pioneer community
C. the keystone species
D. the standing crop

Answer

To solve the question regarding the species composition that invades a barren area and drives the succession, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ecological Succession**:
- Ecological succession is the process through which ecosystems change and develop over time. It involves a series of stages where different species colonize an area, leading to changes in community structure and composition.

**Hint**: Think about how ecosystems evolve and the role of different species in that process.

2. **Identifying Key Terms**:
- In the context of succession, several terms are important:
- **Climax Community**: The final, stable community that results from succession.
- **Pioneer Community**: The first species to colonize a barren area, initiating the succession process.
- **Keystone Species**: A species that has a disproportionately large effect on its environment relative to its abundance.
- **Standing Crop**: The total biomass of living organisms in a given area at a specific time.

**Hint**: Familiarize yourself with these terms and their definitions to understand their roles in ecological succession.

3. **Recognizing the Role of Pioneer Species**:
- Pioneer species are typically hardy organisms that can thrive in harsh conditions. They are the first to invade barren areas (such as after a volcanic eruption or glacial retreat) and prepare the environment for subsequent species by altering the habitat (e.g., by breaking down rocks, accumulating organic matter).

**Hint**: Consider what types of organisms are usually the first to grow in a new or disturbed environment.

4. **Determining the Correct Answer**:
- Given the definitions and roles of the different communities, the species composition that invades a barren area and drives the succession is referred to as the **Pioneer Community**. This is the group that initiates the ecological succession process.

**Hint**: Focus on the term that describes the initial colonizers of barren land.

### Final Answer:
The species composition that invades a barren area and drives the succession is called a **Pioneer Community**.