How is fitness different from general health or vigor?

How is fitness different from general health or vigor?

• A. Fitness is health and vigor.
• B. Fitness is about physical condition.
• C. Fitness measures reproductive success and contribution to the gene pool.
• D. Fitness is about lifespan alone.

Answer: (C)

In evolution, fitness is about how effectively an individual passes its genes to the next generation. It isn’t just about how healthy or vigorous someone is today. Fitness combines survival to reproductive age with the number of offspring that themselves survive and go on to reproduce, so it reflects the genetic contribution to future generations. An organism can be very strong or long-lived but have few or no offspring, in which case its fitness is low; or it can have moderate health but high reproductive success, giving its genes a strong presence in the population. That’s why the best choice says fitness measures reproductive success and contribution to the gene pool. General health, vigor, physical condition, or lifespan alone don’t capture how many of an individual’s genes are actually propagated into future generations.

In evolution, fitness is about how effectively an individual passes its genes to the next generation. It isn’t just about how healthy or vigorous someone is today. Fitness combines survival to reproductive age with the number of offspring that themselves survive and go on to reproduce, so it reflects the genetic contribution to future generations. An organism can be very strong or long-lived but have few or no offspring, in which case its fitness is low; or it can have moderate health but high reproductive success, giving its genes a strong presence in the population.

That’s why the best choice says fitness measures reproductive success and contribution to the gene pool. General health, vigor, physical condition, or lifespan alone don’t capture how many of an individual’s genes are actually propagated into future generations.