In evolutionary terms, what is the term for an organism's ability to survive and reproduce in its environment?

• A. Longevity
• B. Strength
• C. Adaptability
• D. Fitness

Answer: (D)

Fitness is the measure of how well an organism can survive and reproduce in its environment. It isn’t just about living a long life or being physically strong; it centers on reproductive success—the number of offspring that survive to reproduce. Organisms with higher fitness leave more copies of their genes in the next generation, shaping which traits persist in the population through natural selection. Longevity describes lifespan, which can affect fitness but doesn’t by itself equal reproductive success. Strength is a single trait that might help survival or mating, but it doesn’t automatically translate to more offspring. Adaptability describes the ability to handle changing conditions, which can influence future fitness, but the term for the actual reproductive success in a given environment is fitness.