This is a profound statement from Prof Ronald Fernald of Stanford.
"Light has probably been the most profound selective force to act during biological evolution. The 1015 sunrises and sunsets that have taken place since life began have led to the evolution of eyes which use light for vision and for other purposes including navigation and timing. Although eyes occur in a variety of shapes, sizes, optical designs and locations on the body, they all provide similar information about wavelength and intensity to their owners."
Fernald, R. D. (2000). "Evolution of eyes." Curr Opin Neurobiol 10(4): 444-50. The file is here = PDF
[NOTE added 25/11/2011. Since posting this I went and re-checked Fernald's estimate and it is wrong by 3 orders of magnitude. I estimate that there have been 1012 sunrises and sunsets, not 1015 .]
[NOTE added 25/11/2011. Since posting this I went and re-checked Fernald's estimate and it is wrong by 3 orders of magnitude. I estimate that there have been 1012 sunrises and sunsets, not 1015 .]
