Adaptation refers to the process by which populations of organisms become better suited to their environment through natural selection. This process occurs when certain traits or characteristics that confer an advantage in the environment become more common in a population over time.
Fitness, on the other hand, refers to the relative reproductive success of an individual or a population in a given environment. Individuals with traits that confer higher fitness are more likely to survive and reproduce, passing on those advantageous traits to their offspring. In this way, adaptation and fitness are closely related, as adaptations increase the fitness of individuals and populations by allowing them to better survive and reproduce in their environment.
The concept of adaptation and fitness is central to the theory of evolution, as it explains how populations of organisms change over time in response to changing environments. However, it is important to note that adaptations are not perfect, and are always subject to trade-offs and limitations. Additionally, what may be an advantageous trait in one environment may not be in another, highlighting the importance of the relationship between an organism and its environment in shaping the course of evolution.