Given that eyes appear to have evolved multiple times independently through evolution, why has human-level intelligence not evolved more than once? – Quora

Richard Dawkins (in “The Blind Watchmaker”) writes:

“Michael Land reckons that there are nine basic principles for image-forming that eyes use, and that most of them have evolved many times independently. For instance, the curved dish-reflector principle is radically different from our own camera-eye (we use it in radiotelephones, and also in our largest optical telescopes because it is easier to make a large mirror than a large lens), and it has been independently ‘invented’ by various molluscs and crustaceans. Other crustaceans have a compound eye like insects (really a bank of lots of tiny eyes), while other molluscs, as we have seen, have a lensed camera-eye like ours, or a pinhole camera-eye. For each of these types of eye, stages corresponding to evolutionary intermediates exist as working eyes among other modern animals.”

With all respect to Mr. Dawkins, to believe that a structure as complex as any brain has evolved more than once is stretching credulity too far.

Michael Land calls the eyes “the premier sensory outposts of the brain” (see The Evolution of Eyes (1992)), but he only mentions the eye/brain connection three times (and then only in passing), and not in any brain evolution context.

Tags: ,

Comments are closed.