The construction of a beaver dam is an example of which of the following?

• A. Niche construction
• B. Directional selection
• C. Genetic drift
• D. Convergent evolution

Answer: (A)

Verified step by step guidance

1. Understand the concept of 'niche construction': Niche construction refers to the process by which organisms modify their environment, often creating new ecological niches that can influence their own survival and reproduction as well as that of other species.
2. Analyze the behavior of beavers: Beavers build dams to alter their environment, creating ponds that provide them with protection from predators and access to food. This is a clear example of an organism actively modifying its surroundings.
3. Compare 'niche construction' with the other options: Directional selection refers to a type of natural selection that favors one extreme phenotype over others, genetic drift involves random changes in allele frequencies in a population, and convergent evolution describes the process where unrelated species evolve similar traits due to similar environmental pressures.
4. Eliminate incorrect options: The construction of a beaver dam does not involve changes in allele frequencies (genetic drift), does not favor a specific phenotype (directional selection), and is not an example of unrelated species evolving similar traits (convergent evolution).
5. Conclude that the correct answer is 'niche construction' because it directly describes the process of beavers modifying their environment to create a new ecological niche.