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Your Inner Fish is a book about wonder.
Neil Shubin, fish paleontologist and professor of anatomy, writes with wide-eyed and often open-mouthed astonishment
about the history of the human body. The book spans billions of years as he explains the emergence of the human body from other, decidedly less human, forms. Shubin weaves together two main strands of evidence —
physical
and genetic comparisons of humans and other modern-day organisms, and comparisons between humans and fossilized
organisms — in order to tell us what we are and how we got here. In the course of doing so, he awakes in the reader a new understanding of his or her body and the links between it and the creatures around it.
Take teeth, for example. Those unassuming
little body parts turn out to be the foundation of many seemingly-unrelated
structures: we would, as Shubin puts it, “never have scales, feathers, or breasts if we didn’t have teeth in the first place.” As it turns out, the tooth’s pattern of embryonic development is mirrored in the development of scales, feathers, and breasts. All four use the same pattern, but teeth arose first; indeed,
teeth also predate all the other hard parts of the body.
The forerunner of teeth, known to us in fossilized form as “conodonts”, show up all over the place in the early fossil record.
They are often found in the absence of any other body parts, so “…scientists disagreed over whether they were animal, vegetable, or mineral…[c]onodonts were claimed to be pieces of clams, sponges, vertebrates, even worms.” The confusion came about because conodonts appeared in animals that didn’t have any other hard parts — and so no other part of them fossilized. Upon this realization and the discovery of conodonts in the mouths of animals later in the fossil record, the mystery was solved.
Shubin explains all this — and introduces
the scientists who uncovered it — in order to make a larger point: that teeth were the first hard body part to arise and that some of the other hard parts are little more than repurposed
teeth. Indeed, Shubin goes on to discuss some peculiar fish that “look like hamburgers with fleshy tails.” The plate of armor on their heads that gives them such a beefy appearance turns out to be made of hundreds of conodonts fused together.
Shubin treats many different parts of our anatomy according to this pattern: in interlocking chapters, he explains the current form of the body part and then he explains how they got that way, considering,
for their earliest origins and similarities
between extant species. Indeed, the book is remarkable for the breadth of topics it covers. Shubin’s ability to teach about such a wide variety of phenomena is successful largely because he has a real talent for describing complicated and often subtle science in a way that makes it effortless to understand. This is crucial in his being able to share his limitless enthusiasm for the amazing and occasionally baffling paths by which the history of the body proceeded.
The distillation of the science does, however, occasionally go a bit too far: at times, the discussion is so simplified that it feels almost cursory. A conclusion is reached, but the reader is left wanting more details. That said, Shubin does hit precisely the right balance the majority of the time.
The astonishment and wonder with which the book brims is his finest achievement. Nowhere is this more evident than in the passages dealing with Shubin’s experiences on fossil digs and his interpretation of the fossil record. The pages positively burst with excitement and suck the reader in. The excitement is for the glee of scientific discovery, of course, but more, it’s an expression of wonder at the fascinating and almost unbelievable way that the history of the body has unfolded.
As Shubin puts it, “One of the joys of being a scientist is that the natural world has the power to amaze and surprise.” The experience of reading Your Inner Fish is, indeed, one of surprise and amazement, as the reader is left looking at his or her body in a wholly new way, understanding the surprising connections between hernias and the location of the testes in sharks, between alcohol mixing with the gel in the inner ear and drunken stumbling, even between the body layouts
of fruit flies and humans. |
