The sequence of blue-green algae `to` crustose `to` lichens `to` foliose linchens `to` mosses `to` shrubs `to` dicot trees represents

Options

A. genetic mutation
B. ecological succession
C. ecological pyramids
D. evolutionary trend

Answer

To solve the question regarding the sequence of organisms from blue-green algae to dicot trees, we need to analyze the sequence and understand its significance in ecological terms.

### Step-by-Step Solution:

1. **Identify the Sequence**:
The sequence given is:
- Blue-green algae
- Crustose
- Lichens
- Foliose lichens
- Mosses
- Shrubs
- Dicot trees

2. **Understand the Organisms**:
- **Blue-green algae**: These are the first organisms that can colonize bare surfaces, such as rocks. They are photosynthetic and can fix nitrogen.
- **Crustose lichens**: These are formed when blue-green algae (or cyanobacteria) associate with fungi. They can grow on bare substrates, contributing to soil formation.
- **Lichens**: More complex than crustose lichens, they represent a mutualistic relationship between fungi and algae or cyanobacteria.
- **Foliose lichens**: A type of lichen that has leaf-like structures, indicating further ecological development.
- **Mosses**: These are non-vascular plants that require moist environments and can grow in more developed soil.
- **Shrubs**: These are woody plants that can grow in the soil developed by mosses and lichens.
- **Dicot trees**: These are mature trees that represent a climax community in a forest ecosystem.

3. **Concept of Ecological Succession**:
- The sequence represents **ecological succession**, which is the process through which ecosystems develop over time. It starts from bare rock (pioneer species) and moves towards a more complex community (climax community).
- In this case, the sequence illustrates how life progresses from simple organisms (like blue-green algae) to more complex forms (like dicot trees) through a series of stages.

4. **Conclusion**:
- The sequence illustrates the process of ecological succession, where each stage prepares the environment for the next, leading to increased biodiversity and complexity in the ecosystem.

### Final Answer:
The sequence of blue-green algae to dicot trees represents **ecological succession**.