An adaptation is a trait which increases the relative fitness of an individual. The fitness of an individual has 3 components: 1. Probability of survival to reproductive age. 2. Probability of attracting a mate. 3. Average number of offspring. Any trait which increases the fitness of an individual by positively impacting one of these three aspects is considered an adaptation.
There are 2 types of adaptation: physical and behavioral. These are self-explanatory. Physical adaptations could include things like adaptations to morphology or physiology of an organism. Behavioral adaptations are adaptations to, well . . . behavior :)
