Reproductive isolation is essential for speciation. Why?

Explanation

**Step-by-Step Solution:**

1. **Definition of Reproductive Isolation**: Reproductive isolation refers to the mechanisms that prevent different species from interbreeding. This can occur due to various factors such as behavioral differences, temporal differences (mating seasons), or geographical barriers.

2. **Role in Speciation**: Speciation is the process through which new species arise from a common ancestor. Reproductive isolation is crucial for this process because it ensures that once populations diverge, they do not interbreed, allowing them to evolve independently.

3. **Divergence of Populations**: When populations of the same species become separated (for example, due to geographical changes like the formation of islands), they may adapt to their new environments differently. Over time, these adaptations can lead to significant differences in traits.

...