Speaking of the evolution of the eye, recently I began reading the book <i>The Vital Question</i> (Nick Lane), and incidentally, last night I closed my reading on a discussion on that exact topic.<p>Allow me to quote [topic: &#x27;The missing steps to complexity&#x27;, page-45]:<p>&quot;In <i>The Origin of Species</i> Darwin made the point that that natural selection actually predicts that intermediates should be lost. In that context, it is not terribly surprising that there are no surviving intermediates between bacteria and eukaryotes [e.g. plants, humans]. What is more surprising, though, is that the same traits do not keep on
arising, time and time again -- like eyes.<p>We do not see the historical steps in the evolution of eyes, but we do see an ecological spectrum. From a rudimentary light-sensitive spot on some early worm-like creature, eyes have arisen independently on scores of occasions. That is exactly what natural selection predicts. Each small step offers a small advantage in one particular environment, with
the precise advantage depending on the precise environment.
Morphologically distinct types of eye evolve in different environments, as divergent as the compound eyes of flies and mirror eyes of scallops,or as convergent as the camera eyes that are so similar in humans and octopuses. Every conceivable intermediate from pinholes to accommodating
lenses, is found in one species or another. We even see miniature eyes, replete with a &#x27;lens&#x27; and a &#x27;retina&#x27;, in some single-celled protists [e.g. amoeba].&quot;