The image above shows the two forms of the moth Biston betularia, a dark colored form and a light colored form. Prior to the industrial revolution, the trees in England were very light colored and only light colored moths were recorded. Following the Industrial Revolution of the 18th Century, however, a great deal of soot has been deposited on the country side around industrial areas. The soot darkened the surfaces of trees and rocks. In 1848, a dark-colored moth was first recorded. Today, in some areas, 90% or more of the-peppered moths are dark in color. More than 70 species of moth in England have undergone a change from light to dark. Similar observations have been made in other industrial nations, including the United States.