• A number of lines of evidence suggest that species have evolved from a common ancestor, rather than being fixed in form and created separately.

• On a small scale, evolution can be seen taking place in nature, such as in the color patterns of moths, and in artificial selection experiments.

• Natural variation can cross the species border, for example in the ring species of gulls, and new species can be made artificially in the processes of hybridization and polyploidy.

• Homologous similarities between species suggest that the species descended from a common ancestor. Universal homologies - such as the genetic code - found in all living things suggest that all species are descended from a single common ancestor.

• The fossil record provides evidence for evolution in the origin of new species and the order of succession of major groups in the fossil record.