Define fitness in evolutionary terms and distinguish it from general health or vigor.

Define fitness in evolutionary terms and distinguish it from general health or vigor.

• A. Health measures overall well-being but not evolutionary fitness.
• B. Longevity and vigor are the sole determinants of fitness.
• C. Fitness measures an individual's reproductive success and contribution to the gene pool.
• D. Fitness is determined by body size alone.

Answer: (C)

Fitness in evolutionary terms is the ability to pass one's genes to the next generation. It’s measured by reproductive success—the number of offspring that survive to reproduce—and by how those offspring contribute to the gene pool of future generations. This distinguishes fitness from general health or vigor, which describe current condition or physical robustness but don’t guarantee more offspring or genetic transmission. An individual can be very healthy or vigorous yet have few offspring, while another with less apparent vigor might achieve higher reproductive success and thus higher fitness. Fitness is also relative and context-dependent: traits that boost gene transmission in one environment may not in another. So the best description is that fitness reflects reproductive success and contribution to the gene pool.

Fitness in evolutionary terms is the ability to pass one's genes to the next generation. It’s measured by reproductive success—the number of offspring that survive to reproduce—and by how those offspring contribute to the gene pool of future generations. This distinguishes fitness from general health or vigor, which describe current condition or physical robustness but don’t guarantee more offspring or genetic transmission. An individual can be very healthy or vigorous yet have few offspring, while another with less apparent vigor might achieve higher reproductive success and thus higher fitness. Fitness is also relative and context-dependent: traits that boost gene transmission in one environment may not in another. So the best description is that fitness reflects reproductive success and contribution to the gene pool.