Final answer:
Fitness in the context of evolution refers to the relative ability of an organism to survive and reproduce. Direct fitness focuses on an individual's own reproductive success, while inclusive fitness considers the reproductive success of close relatives.
Step-by-step explanation:
Fitness in the context of evolution by natural selection refers to the relative ability of an organism to survive and produce fertile offspring. It is not necessarily about being strong, large, or fast, but rather about how well an organism can adapt to its environment and reproduce successfully. Direct fitness and inclusive fitness are two concepts related to fitness.
Direct fitness refers to an individual's own reproductive success, including the number of offspring they produce. It focuses on an individual's ability to pass on their own genes.
Inclusive fitness takes into account an individual's direct fitness as well as the reproductive success of their close relatives. It considers the benefits an individual gains by helping their relatives reproduce successfully and pass on shared genes.