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 determine which ecological characteristics undergo change during succession, we need to analyze each option provided:

1. **Humus content of soil**:
- During ecological succession, especially in primary and secondary succession, the accumulation of organic matter increases as plants grow, die, and decompose. This leads to an increase in humus content over time.
- **Hint**: Think about how plant growth contributes to soil quality.

2. **Total biomass**:
- In the early stages of succession, biomass may be low as pioneer species establish themselves. As succession progresses, more complex plant communities develop, leading to an increase in total biomass.
- **Hint**: Consider how the number of plants and animals increases as ecosystems mature.

3. **Number of species**:
- Succession typically leads to an increase in biodiversity. Initially, only a few pioneer species may inhabit an area, but as succession continues, more species are introduced and established, increasing the overall number of species present.
- **Hint**: Reflect on how ecosystems become more complex over time.

4. **Temperature**:
- Temperature is largely a physical characteristic of the environment and does not change significantly due to biological succession. It is influenced more by geographical and climatic factors rather than ecological changes.
- **Hint**: Consider what factors influence temperature compared to biological processes.

**Conclusion**:
The characteristics that undergo change during succession are:
- Humus content of soil (a)
- Total biomass (b)
- Number of species (c)

The characteristic that does not undergo change during succession is:
- Temperature (d)

Thus, the answer is all except (d) temperature.

### Summary of Steps:
1. Analyze each ecological characteristic.
2. Determine how each characteristic is affected by succession.
3. Conclude which characteristics change and which do not.