Question

Of the following, which one is the most direct measure of Darwinian fitness?

• A. Adult body size
• B. Lifetime reproductive success
• C. Lifespan
• D. Maximum sprint speed

Hint:

Darwinian fitness is best measured by the number of offspring an individual produces that survive and reproduce, not by physical traits like size or speed.

Answer 1

The Correct Option is B

Darwinian fitness refers to an individual's ability to survive and reproduce in its environment, contributing to the gene pool of the next generation.

Step 1: Understand Darwinian fitness.
Fitness is most directly measured by the number of viable offspring an individual produces that survive to reproduce. This is known as lifetime reproductive success.

Step 2: Evaluate options.
- Option (A): Adult body size may correlate with fitness but is not a direct measure of reproductive success.
- Option (B): Lifetime reproductive success is the most direct measure, as it directly quantifies the number of offspring produced.
- Option (C): Lifespan alone does not indicate reproductive success. An individual may live long but produce few offspring.
- Option (D): Maximum sprint speed is unrelated to overall reproductive success or fitness in terms of gene contribution.

Step 3: Conclusion.
The most direct measure of Darwinian fitness is lifetime reproductive success, making option (B) the correct answer.