Mutation

A mutation is an alteration in an organism's DNA that can bring about a range of effects. Mutations may have little or no effect, they may be harmful, or they may be beneficial to the organism. Beneficial mutations are known as adaptations. Mutations typically occur randomly and not as a result of specific environmental factors or pressures. 

Adaptation

An adaptation is a mutation that bestows the organism with advantageous features that enhance its fitness to its environment. In this instance, fitness refers to the organism’s likelihood of surviving and reproducing in its native environment. Adaptations are favored by selection as they provide organisms with a selective advantage in that particular environment.