Question

Which of the following factors produce and redistribute variations?
A. Mutation
B. Natural selection
C. Gene flow
D. Recombination
Choose the correct answer from the options given below:

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

Hint:

To remember the evolutionary forces, categorize them:
{Creates new variation:} Mutation
{Shuffles/Redistributes variation:} Recombination, Gene Flow
{Filters/Changes frequencies of variation:} Natural Selection, Genetic Drift

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Evolutionary change is driven by processes that introduce, shuffle, and filter genetic variation within and between populations. The question asks to identify which factors are responsible for creating new genetic variation (produce) or shuffling existing variation into new combinations (redistribute).
Step 2: Detailed Explanation:
- A. Mutation: This is the ultimate source of all new genetic variation. A mutation is a change in the DNA sequence, creating new alleles. Therefore, it produces variation.
- B. Natural selection: This is a mechanism that acts upon existing variation. It is a process of differential survival and reproduction, where certain traits are favored over others. Natural selection reduces or maintains variation; it does not produce or redistribute it.
- C. Gene flow: This is the transfer of alleles from one population to another through migration. It redistributes variation by introducing alleles from one population's gene pool into another's.
- D. Recombination: This process, occurring during meiosis (specifically, crossing over), shuffles existing alleles on chromosomes to create new combinations in offspring. It is a major source of genetic shuffling and thus redistributes variation.
Step 3: Final Answer:
Mutation (A) produces new variation. Gene flow (C) and Recombination (D) redistribute existing variation. Natural selection (B) is a filtering mechanism, not a source or redistributor of variation. Therefore, the correct factors are A, C, and D.