DOI link for Background
Creationists are split into old earthers and new earthers according to whether they accept geological evidence for deep time. Several types of evidence for evolution were available to Charles Darwin. This evidence demonstrated that organisms had, in fact, changed over time and that mechanisms that Darwin suggested for evolution did, in fact, cause biological change. Fossils are visible traces of organisms that lived in the past and, therefore, provide direct evidence for earlier life. Artificial selection demonstrates that biological change over generations in organisms can be achieved by a selection process and thus is an important type of evidence for Darwin’s mechanism for evolutionary change. The example shows that evolution is a process; selection continues as the environment changes, and, in fact, evolutionary changes can lead to the very environmental changes that lead to continued selection. The major evolutionary forces are selection, mutation, chance, and gene flow.