books.google.co.nz - "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...http://books.google.co.nz/books/about/Evolution_s_Witness.html?id=ftpQB_GjtJgC&utm_source=gb-gplus-shareEvolution's Witness
