What does the 'fitness' of a species mean?

The 'fitness' of a species refers to its ability to survive, reproduce, and pass on its genes to future generations in a given environment. It encompasses not just physical traits but also behavioral and ecological adaptations that enhance survival. Higher fitness means a greater likelihood of contributing offspring to the next generation, thereby influencing the overall gene pool. Fitness is often measured in relation to other species and can change over time due to environmental pressures and evolutionary processes.