An organism's DNA affects how it looks, how it behaves, and its physiology. So a change in an organism's DNA can cause changes in all aspects of its life. Mutations are essential to evolution; they are the raw material of genetic variation. Without mutation, evolution could not occur.
The theory of organic evolution, developed by Charles Darwin in the mid-1800s, revolutionized taxonomy. Thus, modern taxonomists who study plants or animals do not merely name and catalog species, they also try to construct evolutionary trees showing the relationships of different species
