Which of the following is NOT a common mechanism by which reproductive isolation occurs during speciation?

• A. Mechanical isolation
• B. Genetic drift
• C. Behavioral isolation
• D. Temporal isolation

Answer: (B)

Verified step by step guidance

1. Understand the concept of reproductive isolation: Reproductive isolation refers to mechanisms that prevent different species from interbreeding and producing viable, fertile offspring. These mechanisms are crucial for the process of speciation, where one species splits into two or more distinct species.
2. Review the types of reproductive isolation: Common mechanisms include mechanical isolation (differences in reproductive structures), behavioral isolation (differences in mating behaviors), and temporal isolation (differences in timing of reproduction). These mechanisms prevent gene flow between populations.
3. Analyze the term 'genetic drift': Genetic drift is a random change in allele frequencies within a population due to chance events. While it can influence the genetic makeup of populations, it is not a direct mechanism of reproductive isolation. Instead, it is a process that can contribute to evolutionary changes over time.
4. Compare genetic drift to the other options: Mechanical, behavioral, and temporal isolation are all direct mechanisms that prevent interbreeding between populations, whereas genetic drift does not directly prevent reproduction but rather affects genetic variation within populations.
5. Conclude that genetic drift is NOT a common mechanism of reproductive isolation: Based on the definitions and roles of each term, genetic drift does not fit the criteria of a reproductive isolation mechanism, making it the correct answer to the question.