<human>:  Can you explain the difference between the theories of evolution and natural selection?
<bot>: Evolution is the process by which species of living organisms have changed over time and have adapted to the changes in their environment. Natural selection, on the other hand, is the process by which those species that are best adapted to their environment survive and reproduce, while those that are less adapted are less likely to survive and reproduce. This difference of survival and reproduction leads to the development of new species over time. In other words, evolution is the process by which species change over time, and natural selection is the mechanism that allows certain members of a species to survive and reproduce more successfully than others.