Final answer:
Adaptive behaviors increase an animal's fitness and can evolve through natural selection if they provide a survival or reproductive advantage and are genetically based.
Step-by-step explanation:
Adaptive behaviors enhance an animal's fitness because they allow animals to adjust to unexpected events, leading to the development of behaviors that may be more advantageous in subsequent similar occurrences.
For example, wolves hunting in packs is an adaptive behavior that increases their chances of obtaining food, thereby improving their fitness. In contrast, a behavior like a squirrel sounding an alarm to warn others of a predator seems counterintuitive to individual fitness, but such behaviors may still prevail if they ultimately benefit the species as a whole.
Through the process of evolution by natural selection, behaviors that improve an animal's fitness may become more common. Behaviors controlled by genes have the potential to evolve, especially if they result in higher survival and reproductive rates. These beneficial behaviors are passed down to future generations, becoming more frequent within the population. Conversely, behaviors that diminish fitness are less likely to continue.
In summary, most animal behaviors are the result of both genetic makeup and environmental experiences. When such behaviors confer a survival advantage, they are subject to natural selection and can lead to increased adaptation within a species.