which of the following ecological characteristics undergo change during succession? (a) Humus content of soil (b) total biomass (c) number of species (d) temperature

Options

A. all except (a)
B. all except (b)
C. all except (c)
D. all except (d)

Answer

To solve the question regarding which ecological characteristics undergo change during succession, we can analyze each of the options provided:

1. **Understanding Succession**: Succession is a natural process where an ecological community undergoes changes over time, leading from a barren environment to a more complex ecosystem, often reaching a climax community.

2. **Analyzing Each Option**:
- **(a) Humus content of soil**: During succession, as pioneer species colonize the barren land, they contribute organic matter to the soil, increasing the humus content. Therefore, this characteristic does change during succession.

- **(b) Total biomass**: As succession progresses, the number of plants and animals increases, leading to greater biomass. Thus, total biomass also changes during succession.

- **(c) Number of species**: In the early stages of succession, few species are present. As the ecosystem develops, more species (including plants, animals, and microorganisms) are introduced, leading to an increase in species diversity. Hence, the number of species does change during succession.

- **(d) Temperature**: Temperature is primarily influenced by climatic conditions and does not directly change due to ecological succession. It remains relatively constant regardless of the changes in the community structure.

3. **Conclusion**: Based on the analysis, the characteristics that undergo change during succession are:
- Humus content of soil (a)
- Total biomass (b)
- Number of species (c)

The only characteristic that does not change is temperature (d).

**Final Answer**: The correct answer is (a), (b), and (c) undergo change during succession, while (d) does not.