Evolution's Witness: How Eyes Evolved
With predation and carnivory as catalysts, the first known eye appeared in a trilobite during the Cambrian explosion approximately 543 million years ago. This period was a crucible of evolution and teemed with anatomic creativity although the journey to formed vision actually began billions of years before that. The Cambrian period, however, spawned nearly all morphologic forms of the eye, followed by descent over hundreds of millions of years providing an unimaginable variety of eyes with at least ten different designs. Some eyes display spectacular creativity with mirror, scanning or telephoto optics. Some of these ocular designs are merely curiosities, while others offer the finest visual potential packed into a small space, limited only by the laws of diffraction or physiological optics.