Evolution and the eye: the Darwin bicentennial and the sesquicentennial of the origin of species.

Evolution is an essential concept for anyone who considers science to be the best way to understand the natural world. It is as fully established as any scientific principle can be and is the great unifying theme in all of biology, as integral to understanding life-forms as gravity is to understanding the cosmos. On the bicentennial of the birth of Charles Darwin in 1809, and 150 years after the publication of On the Origin of Species by Means of Natural Selection in 1859, we should remember the main features of eye evolution and the prominent place the eye holds in the development and refinement of evolutionary theory. A few highlights include the antiquity of rhodopsin, the ready capacity of an eye to evolve, the effect of eyes on the diversification of life-forms, and the promising influence of genetics on developmental and evolutionary biology.