Another instance of a misleading passage in Complexity: A Guided Tour:

Another example where Evo-Devo is challenging long-held views about evolution concerns the notion of convergent evolution. In my high school biology class, we learned that the octopus eye - greatly different in morphology - were examples of convergent evolution: eyes in these two species evolved completely independently of one another as a consequence of natural selection acting in two different environments in which eyes were a useful adaptation.

However, recent evidence has indicated that the evolution of these two eyes was not as independent as previously thought. Humans, octopi, flies, and many other species have a common gene called PAX6, which helps direct development of eyes. In a strange but revealing experiment, the Swiss biologist Walter Gehring took PAX6 genes from mice and inserted them into the genomes of fruit flies. In particular, in different studies, PAX6 was inserted in three different parts of the genome... The researchers got eerie results: eye-like structures formed... Gehring's conclusion: the eye evolved not many times independently, but only once, in a common ancestor with the PAX6 gene. This conclusion is still quite controversial among evolutionary biologists.

The author clearly doesn't understand the concept of convergent evolution here. The PAX6 gene, a master regulator transcription factor that controls eye development, certainly existed in the common ancestor of mammals and octopuses. But having the PAX6 gene is not the same thing as actually having an eye. The common ancestor of octopuses and humans did not have the kind of complex eye found an octopus or a human - the kind with a lens, an iris, etc. It probably had some sort of light-sensitive spot.

Thus, while the PAX6 gene in an octopus is homologous to the PAX6 gene in humans, the actual eyes themselves are not homologous and are in fact a great example of convergent evolution "as a consequence of natural selection acting in two different environments in which eyes were a useful adaptation." The lens, iris, and perhaps even the retina and optic nerve as well, all evolved independently in octopi and vertebrates, by means of a homologous gene that already existed in the common ancestor of mammals and octopuses. This is not controversial among biologists, and neither are the cool PAX6 results.

The biology tourism in this guided tour of complexity is one of the most frustrating asepcts of the book. Over and over the author writes that new ideas, somehow associated with the emerging science of complexity, are overturning and challenging long-held views. And yet all of her examples are basically like the one above: an unsophisticated understanding of biology coupled with hype about supposedly new ideas. (Evo-Devo in this book is put in a chapter on network thinking, even though the science of networks has contributed nothing to Evo-Devo, which is basically a merger of molecular developmental biology with evolution.)

I want to believe, I really do, that the science of computation, that network statistics, Turing machines, cellular automata, chaos theory, etc. have something fruitful to contribute to molecular biology and evolution. But I always come away disappointed.

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