The Grand Canyon, shown here, is an American icon and one of the wonders of the natural world. People come from all over the world to view this natural wonder. The Grand Canyon is also a record of the past. Look at the rock layers in the picture. If you were to walk down a trail to the bottom of the canyon, with each step down you would be taking a step back in time. That’s because lower layers of rock represent the more distant past. The rock layers and the fossils they contain show the history of Earth and its organisms over a 2-billion-year time span.
Although Charles Darwin never visited the Grand Canyon, he saw rock layers and fossils in other parts of the world. They helped inspire his theory of evolution. Darwin’s theory rocked the scientific world. You will read why in the following concepts.