What is natural selection and how is it different from evolution?

Natural selection can be defined as: The gradual process in which inherited characteristics become more or less common in a population, in response to the environment determining the breeding success of individuals possessing those characteristics. For example: A brown bear, in a snowy landscape, has a MUTATION that makes its fur white. This leads to increased VARIATION in the population of brown bears. The white bear has a COMPETITIVE ADVANTAGE over the brown bears because it can camouflage and is therefore more likely to catch prey. The white bear is better fed and is therefore more likely to survive (SURVIVAL OF THE FITTEST) and REPRODUCE. The advantageous allele is INHERITED, therefore the offspring of the white bear are also white. If the landscape remains snowy, the white furred offspring are more likely to survive and therefore reproduce, resulting in a change of the proportion alleles that code for fur colour in the population over time. On the other hand, evolution can be defined as: A change in genetic code or phenotype over time, often resulting in speciation. Using the previous example, evolution would be the change in the proportion of alleles coding for white and brown fur over time, whereas natural selection is the process that caused the change i.e. mutation, variation, competitive advantage, survival of the fittest, reproduction and passing on of advantageous alleles.