Evolution is the process by which a specific change its characteristics over multiple generations.
Natural selection involves the process of evolving with the phenomenon of survival of the fittest.
It acts as a mechanism of nature by which evolution is driven or caused.
The species can survive and evolve to a new environment via natural selection.
Example of evolution via natural selection is the origin of the long necks of giraffes to eat leaves from the top of the tree from the ancestral species which had necks of ordinary length similar to deer or antelope.