In autogenic succession

Options

A. early and continued dominance of autotrophic organism takes place like green plants
B. replacement of existing communities cause largely by any other external condition
C. early dominance of heterotrophs takes place such as bacteria, fungi and other animals
D. community itself modifies its own environment thus causing its own replacement by new communities.

Answer

**Step-by-Step Solution:**

1. **Understanding Autogenic Succession**:
- The term "autogenic" is derived from "auto," meaning self, and "genic," meaning producing or causing. Thus, autogenic succession refers to ecological succession that is driven by biotic factors within an ecosystem.

2. **Role of Biotic Factors**:
- Biotic factors are the living components of an ecosystem, including plants, animals, and microorganisms. In autogenic succession, these living organisms play a crucial role in driving the changes within the ecosystem.

3. **Example of Autogenic Succession**:
- An example of autogenic succession can be seen in plant communities. The plants themselves can cause changes in the environment that lead to succession. For instance, as certain plants grow and die, they alter the soil composition, light availability, and other environmental factors, which can facilitate the growth of other plant species.

4. **Definition of Succession**:
- Succession refers to the gradual changes in community structure over time. It is a process where one community replaces another in a sequential manner, leading to a more stable ecosystem.

5. **Characteristics of Autogenic Succession**:
- In autogenic succession, the changes are primarily driven by the organisms within the community. The existing community modifies its own environment, leading to its replacement by a new community. This means that the community itself is responsible for the changes that occur.

6. **Identifying the Correct Statement**:
- Among the statements provided regarding autogenic succession, the correct one is that the community itself modifies its own environment, thus causing its own replacement by a new community. This highlights the self-driven nature of autogenic succession.