Question

Which of the following phenomena can lead to microevolution?
A. Natural Selection
B. Sexual Selection
C. Genetic Drift
Choose the most appropriate answer from the options given below:

• A. A and B only
• B. B and C only
• C. A and C only
• D. A, B and C

Hint:

Remember the five main fingers of evolution that cause changes in allele frequency (microevolution):

Small population size (Genetic Drift)
Non-random mating (Sexual Selection)
Mutation
Gene Flow (Migration)
Natural Selection (Adaptation)
All options in the question are on this list.

Answer 1

The Correct Option is D

Step 1: Concept Overview:
Microevolution is defined as shifts in allele frequencies within a population across generations, representing small-scale evolutionary changes within a species. The question identifies mechanisms driving these shifts.

Step 2: Detailed Explanation:
- A. Natural Selection: This process favors the survival and reproduction of individuals with advantageous heritable traits, leading to an increased prevalence of beneficial alleles and driving microevolution.
- B. Sexual Selection: A form of natural selection where mating success determines gene transmission. Traits enhancing mate acquisition become more prevalent, altering allele frequencies.
- C. Genetic Drift: Random variations in allele frequencies between generations due to chance, particularly in small populations. This non-adaptive mechanism can cause alleles to be lost or fixed, resulting in microevolutionary change.

Step 3: Conclusion:
Natural Selection, Sexual Selection, and Genetic Drift all demonstrably cause changes in population allele frequencies. Consequently, all three contribute to microevolution. The correct answer is (D).