Review

"God created a number of possibilities in case some of his prototypes failed -- that is the meaning of evolution."

The field of evolutionary biology is on the verge of an exciting new age of discovery. In Your Inner Fish, Neil Shubin narrates the story of evolution by tracing the organs of the human body back to millions of years, long before the first creatures walked the earth. The book’s stimulating title indicates that the central thrust is evolutionary—seeking to explain humans as the product of a succession of life forms from an original cell. By examining fossils and DNA, Shubin shows us that our hands actually resemble fish fins, our head is organized like that of a long-extinct jawless fish, and major parts of our genome look and function like those of worms and bacteria.

Written largely in the first person, this lively and convincing account begins with Shubin’s archeological expeditions or adventures finding fossils that conveys the excitement and also the frustrations. He brings his discoveries back to the lab and starts to link them with limb development and eventually with genes and DNA, ZPA and the action of retinoic acid. Subsequent chapters focus on the history of discoveries of the embryonic origins and genetic control mechanisms at work in different regions of the body. Shubin’s description of patterns common in the development of appendages, teeth, the vertebrate head, body plans, and sensory systems are extolled with quirky and little-known facts that add interest and intrigue. More deeply, he reveals the connections between humans and multicellular organisms at the cellular and molecular levels and the relationship of those connections to features prefigured in unicellular organisms.

The author draws remarkable analogies between body parts of creatures which otherwise differ widely. He discusses how all advanced creatures have similar architecture. The author explains how they have heads containing brains and sense organs, spinal columns...