Thursday, December 4, 2008

Book Review: Your Inner Fish

Shubin, Neil. Your Inner Fish: A Journey into the 3.5 Billion-Year History of the Human Body. New York: Pantheon, 2008.

Neil Shubin, an evolutionary biologist who works as Provost of the Field Museum of Natural History in Chicago, clearly chose the right career. In Your Inner Fish: A Journey into the 3.5 Billion-Year History of the Human Body, Shubin traces the history of our anatomy with a passion that leaps off the page. His conversational writing style, coupled with animated anecdotes and crisp descriptions, energized my reading so that two hundred pages seemed more like twenty.

The title of the book, Your Inner Fish, refers to the evolutionary history we humans share with other animals. Shubin, who also acts as Professor of Anatomy and Associate Dean at the University of Chicago, opens with the tale of how he co-discovered Tiktaalik roseae, sometimes called the “fish that crawled out of the water,” in the Canadian Arctic in 2006. This groundbreaking find provides compelling evidence of an intermediate stage between fish and early limbed animals, and serves as an illustration of the “history of life within us,” one example among many that Shubin highlights.

Of course, Charles Darwin predicted that transitional forms would illustrate a gradual evolutionary shift between two distinct groups, and Tiktaalik fits the bill. Like most fish, Tiktaalik possessed gills, scales, and webbed fins. Yet, it also sported innovations like wrists, lungs, and a mobile neck, and it denotes the earliest creature to possess all the bones of our arm, wrist, and palm. Previous to Tiktaalik, fish did not exhibit these joints. Thus, this creature laid the stepping-stones for later vertebrates to transition onto dry land.

The author tells us why we should care about this: "Virtually every illness we suffer has some historical component. ... [D]ifferent branches of the tree of life inside us – from ancient humans, to amphibians and fish, and finally to microbes – come back to pester us today … show[ing] that we were not designed rationally, but are products of a convoluted history."

He pinpoints the evolutionary history of our senses of smell, sight, and hearing, as well as that of our wrists, teeth, jaws, and skull, and he explains such common ailments as hiccups, hernias, and sleep apnea.

In a poignant passage about dissecting the human hand, Shubin recalls his personal introduction as a student to human anatomy. After spending months dissecting internal organs, he felt detached about the task before him. Seeing the hand jolted him back to reality: “[s]uddenly this mechanical exercise, dissection, became deeply and emotionally personal.” Similarly, when he examined Tiktaalik’s modified fin for the first time, he felt that he had “uncovered a deep connection between my humanity and [that of] another being,” which is the whole premise of his book.

Your Inner Fish provides a fascinating overview of the history of our own evolution, an introduction that is both readable and inviting. I suppose the simple explanations and introductory tone Shubin uses might give more well-read students seeking in-depth analysis or discussion, reason to criticize, but for a non-scientist reader such as myself, Shubin strikes the right note for piquing my interest further. And simply by asking what evolution from our animal ancestors really means for us, Shubin makes the book personally relevant in a modern context.

Shubin concludes with an inspiring message: "I can imagine few things more beautiful or intellectually profound than finding the basis for our humanity, and remedies for many of the ills we suffer, nestled inside some of the most humble creatures that ever lived on our planet."

Roxanne Enman

(Posted as "Our Evolutionary Branch, Demystified" under the hardcover version on at

No comments: