Which of the following does NOT tend to promote speciation?

• A. Natural selection in different environments
• B. Gene flow between populations
• C. Genetic drift in small populations
• D. Geographic isolation

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the concept of speciation. Speciation is the process by which populations evolve to become distinct species. It often occurs when populations are isolated and subjected to different evolutionary pressures.
2. Step 2: Analyze each option provided in the question. Natural selection in different environments can lead to speciation because populations adapt to their specific environments, resulting in divergence over time.
3. Step 3: Consider the role of genetic drift in small populations. Genetic drift refers to random changes in allele frequencies, which can lead to divergence between populations, especially in small populations, promoting speciation.
4. Step 4: Examine geographic isolation. Geographic isolation physically separates populations, preventing gene flow and allowing them to evolve independently, which is a key driver of speciation.
5. Step 5: Evaluate the impact of gene flow between populations. Gene flow involves the exchange of genetic material between populations, which tends to homogenize genetic differences and prevent divergence, thereby NOT promoting speciation.