The tendency towards increased variety and density of species at community junctions is known as the

Options

A. Biotic potential
B. Variability
C. Vital index
D. Edge effect

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the term that describes the tendency towards increased variety and density of species at community junctions.

2. **Identifying Key Terms**: The key terms in the question are "increased variety," "density of species," and "community junctions."

3. **Exploring Possible Answers**: The video transcript mentions several terms: biotic potential, variability, vital index, and edge effect. We need to determine which of these relates to the increased variety and density of species at community junctions.

4. **Analyzing the Edge Effect**: The transcript states that the edge effect is associated with increased variety and density of species at the junction of two communities. This is where two different ecosystems meet, such as a forest and a grassland or land and sea.

5. **Differentiating Other Terms**:
- **Biotic Potential**: Refers to the maximum reproductive rate of a population, not directly related to species diversity at junctions.
- **Variability**: Refers to genetic variations within a population, not specifically about community junctions.
- **Vital Index**: This is the ratio of birth to death rates in a population, which does not pertain to species diversity at junctions.

6. **Conclusion**: Based on the analysis, the term that describes the tendency towards increased variety and density of species at community junctions is the **edge effect**.

---