Question

Match the following:

• A. A-III, B-IV, C-I, D-V
• B. A-II, B-IV, C-V, D-I
• C. A-III, B-V, C-I, D-II
• D. A-III, B-IV, C-I, D-II {Correct Answer:} (3) A-III, B-V, C-I, D-II

Hint:

Natural selection can take different forms—directional selection favors one extreme trait, while genetic drift and bottleneck effects lead to random changes in allele frequencies.

Answer 1

The Correct Option is C

Directional selection (A-III): A type of natural selection where an advantageous trait (e.g., DDT resistance in mosquitoes) becomes more common over time.
Genetic load (B-V): The accumulation of harmful mutations can lead to genetic disorders like sickle cell anaemia.
Bottleneck effect (C-I): A sudden reduction in population size causes genetic drift, leading to traits like polydactyly in dwarfs.
Centrifugal selection (D-II): Occurs when multiple advantageous traits are selected, as seen in Darwin’s finches adapting to different environments.

Answer 2

To solve this problem, we need to match the terms in List-1 with their correct descriptions in List-2.

1. Understanding the Terms:
Let's analyze the terms from List-1 and their possible corresponding descriptions in List-2:

• A. Directional selection: Directional selection is a type of natural selection where one extreme phenotype is favored over others. An example of this is Darwin's finches, where beak size evolved based on food availability, making the correct match A-III.
• B. Genetic load: Genetic load refers to the accumulation of deleterious alleles in a population. This is commonly associated with the presence of harmful recessive alleles, which in turn can lead to conditions like sickle cell anemia. Therefore, the correct match is B-V.
• C. Bottle neck effect: The bottle neck effect occurs when a population's size is drastically reduced, leading to a loss of genetic diversity. This effect can be seen in the resistance of mosquitoes to DDT, which is a result of selective survival. Thus, the correct match is C-I.
• D. Centrifugal selection: Centrifugal selection refers to the selection pressures that push traits towards extreme variation. This can be seen in the case of the tailed human baby, as an example of an adaptation. Therefore, the correct match is D-II.

2. Conclusion:
The correct matches are:

• A-III (Directional selection and Darwin's finches)
• B-V (Genetic load and Sickle cell anemia)
• C-I (Bottle neck effect and DDT resistant mosquitoes)
• D-II (Centrifugal selection and Tailed human baby)

Final Answer:
The correct answer is Option C: A-III, B-V, C-I, D-II.