I understand that this book has spawned a fairly popular BBC production, which I should probably check out. I picked the book up because I was looking for answers to lingering questions I’ve had about evolution, and was pleased to find not only the answers I was looking for, but answers to a lot of questions I probably should have been asking! A serviceable analogy is to imagine Shubin as a magician revealing his trade secrets. Before I read this, the idea of nature having separately created so many specialized adaptations seemed almost incomprehensible. Then Shubin reveals the “behind the curtain” manipulations of natural selection and change over time, and suddenly these outcomes seem not just explicable, but even just a little obvious. I expect this is how Watson felt every time Sherlock Holmes revealed the logical process that lay behind his seemingly “miraculous” deductions. Evolutionary science is by no means “elementary,” but in Shubin’s hands it is revealed to be both logical and credible.
Essentially, the book traces the ancient antecedents of our human anatomy back to their evolutionary beginnings. Some of our traits are relatively newly acquired – our sense of smell, for instance. But the basic genes that establish our body shape – that distinguish “head” from “tail”, and “left” from “right”, for instance – are ancient indeed, originating from genes that have been around since the first jellyfish populated primordial oceans.
The book tackles our basic body systems one at a time, using evidence from paleontology, embryology and genetics to painstakingly track the evolution of each body part from its origins to its modern day form/function. For instance, the author tracks how bones that used to form part of reptilian skulls in time came to be repurposed as mammalian earbones; how nerves that used to enable fish to use their throats to both breathe and eat gradually came to control the muscles that pump our heart (inefficiencies in this “jury rigged system” are to blame for hiccups, by the way); and how the genes that used to produce gills in fish have been repurposed by evolutionary pressures to create the features of our human faces.
Though the first few chapters were on the dry side, I eventually began warming to the topic and by the end was reading enthusiastically. This experience, however, inclines me to be cautious about recommending Inner Fish to others. In spite of the author’s herculean efforts to make the content entertaining and accessible, folks looking for a light scientific read or who have forgotten most of what they learned in 9th grade biology may find parts of this a tough slog. If, however, you find yourself (like me) wondering how the millions of specialized creatures inhabiting the earth today can possibly have evolved from clumps of primodial ooze, then I think you’ll find this book both fascinating and informative.