Indeed, the gene which is responsible for producing the photo sensitive protein rhodopsin, the molecular basis of vision in all complex animals, appears to be very ancient, and first arose in a blue green algae. So the most primitive eye probably arose some time near when single called life first developed oxygen photosynthesis,around 2.2-2.5 billion years ago.
How the gene made the jump into ancestors of animals is unclear.
How the gene made the jump into ancestors of animals is unclear.
