In which of the following situations is adaptive radiation least likely to occur?

• A. A mass extinction event that leaves many ecological niches vacant
• B. A newly formed volcanic island with many unoccupied habitats
• C. A population colonizing a new area with diverse resources and little competition
• D. A stable environment with little ecological change and few available niches

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the concept of adaptive radiation. Adaptive radiation refers to the rapid evolution of diverse species from a common ancestor when new ecological niches become available. This typically occurs in environments with abundant resources and minimal competition.
2. Step 2: Analyze the scenarios provided in the problem. Adaptive radiation is most likely to occur in situations where there are unoccupied habitats, diverse resources, or ecological niches that can be exploited by organisms. Conversely, it is least likely to occur in stable environments with little ecological change.
3. Step 3: Evaluate each option: - A mass extinction event creates vacant ecological niches, which can lead to adaptive radiation. - A newly formed volcanic island provides unoccupied habitats, promoting adaptive radiation. - A population colonizing a new area with diverse resources and little competition also encourages adaptive radiation. - A stable environment with little ecological change and few available niches does not provide the conditions necessary for adaptive radiation.
4. Step 4: Identify the correct answer based on the analysis. The scenario least likely to result in adaptive radiation is the one where the environment is stable, with little ecological change and few available niches.
5. Step 5: Summarize the reasoning. Adaptive radiation requires ecological opportunities, such as unoccupied niches or diverse resources. A stable environment with few changes does not provide these opportunities, making it the least likely scenario for adaptive radiation to occur.