Which of these is not a characteristic of fitness?

The concept of fitness in ecology and evolution refers to an organism's ability to survive and reproduce in its environment. Fitness can indeed be influenced by various traits that affect an individual's reproductive success. However, the assertion that fitness works only on traits such as size and speed is overly simplistic.

Fitness encompasses a wider range of traits, depending on environmental conditions and species characteristics. These traits can include behavioral adaptations, reproductive strategies, and physiological capabilities, among others. While size and speed might contribute to an individual's fitness in specific contexts—such as predator avoidance or competitive interactions—they do not encompass the full scope of what fitness entails.

Fitness being environment-specific means that what may enhance fitness in one habitat might not do so in another, highlighting the adaptiveness of various traits. The species-specific nature of fitness indicates that different species may exhibit different adaptations that contribute to their fitness in their respective environments. Lastly, measuring fitness across several generations provides insight into how traits can influence evolutionary changes and natural selection over time, reinforcing that fitness is a dynamic concept rather than a static one based solely on physical attributes like size or speed.