Which of the following would be least likely to be a cause of natural selection in a population?

• A. Differential reproductive success due to environmental pressures (some individuals leave more offspring than others)
• B. A change in allele frequencies caused by a random event (genetic drift)
• C. Genetic variation among individuals that affects survival or reproduction
• D. Heritable traits being passed from parents to offspring

Answer: (B)

Verified step by step guidance

1. Understand the concept of natural selection: it is the process where individuals with certain heritable traits tend to survive and reproduce more successfully due to environmental pressures, leading to changes in allele frequencies over generations.
2. Identify the key factors that drive natural selection: these include differential reproductive success caused by environmental pressures, genetic variation affecting survival or reproduction, and the heritability of traits from parents to offspring.
3. Recognize that genetic drift, which is a change in allele frequencies caused by random events, is a separate evolutionary mechanism and does not rely on differential reproductive success or environmental pressures.
4. Compare each option to the definition of natural selection to determine which one does not fit: natural selection requires non-random survival and reproduction based on traits, whereas genetic drift is random and not driven by trait advantages.
5. Conclude that the least likely cause of natural selection in a population is the change in allele frequencies caused by a random event (genetic drift), because it operates independently of environmental pressures and differential reproductive success.