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: Understanding the Concept:
Microevolution is defined as the change in allele frequencies in a population over successive generations. It refers to small-scale evolutionary changes within a species. The question asks which of the given mechanisms cause these changes.

Step 2: Detailed Explanation:
- A. Natural Selection: This is the process where individuals with certain heritable traits survive and reproduce at higher rates than other individuals because of those traits. This leads to an increase in the frequency of advantageous alleles and is a primary driver of microevolution.
- B. Sexual Selection: This is a specific type of natural selection in which mating success determines the passing of genes to the next generation. Traits that increase an organism's chances of securing a mate will become more common over time, thus changing allele frequencies.
- C. Genetic Drift: This refers to random fluctuations in allele frequencies from one generation to the next due to chance events, especially in small populations. It is a non-adaptive mechanism that can lead to the loss or fixation of alleles, causing microevolutionary change.

Step 3: Final Answer:
All three listed phenomena—Natural Selection, Sexual Selection, and Genetic Drift—are established mechanisms that cause changes in allele frequencies in a population. Therefore, all three lead to microevolution. The correct answer is option (D).