How are embryos like fossils? How did we come to have the hands, arms, heads, bone structures, ears, eyes and many of the other parts we have? It turns out that homo sap is a very jury-rigged critter, an accumulation of biological compromises and re-purposed parts. One can look at fossils to see how we got from there, waaaay back there, to here, and one can also find, in comparing embryos of different species, evidence of our developmental history. DNA tells tales. Neil Shubin follows both paths on his road to our past in a book that demonstrates popular science writing at its best.

There is a wealth of fascinating material in this easy-to-read book on how human anatomy came to be. Paleontology, like Con Edison, swears by the motto “Dig we Must.” Shubin offers a quick intro into how one decides where one should dig to increase the odds of finding what you are looking for. He should know. Currently both a professor at the University of Chicago and Provost of the Field Museum, his primary claim to fame was as the person who located in the Canadian Arctic, a fossil, Tiktaalik roseae, a flat-headed fish/amphibian that marked the transition of animals from sea to land. This was front page news across the world in 2004.

Looking at how embryos develop one can see remarkable similarities among species. Human embryos look a lot less different from embryos of other species than we as adults look from the fuller versions of other critters. Plunging into the DNA of each holds many answers. In Your Inner Fish, Shubin looks at different parts of the human body, for example teeth, and hands and arms, eyes and ears, then traces their structures back through the scientific record to see where each bit first appeared. This is way cool, and gives one some perspective into just how much we, as humans, are part of all life on earth (and who knows where else?)

Did you know that "the head is made up of vertebrae that fused and grew a vault to hold our brains and sense organs?” (p 88) How about that “bones that are the upper and lower jaws in sharks are used by us to swallow and hear.” (p 92) There are many revelations of this sort. I was most impressed by a section that described how our ear was related to a sense organ, the neuromast, present in the sides of some fish. This figures prominently in our reaction to over-imbibing. People who overindulge in spirits experience spins. This has to do with a side-effect of alcohol not mixing well with the water in one’s ear, the ear that helps regulate our sense of balance. Just as the neuromast lets fishes know about the world around them, acting as a sense, and ultimately, balance organ, so too our ears use a very similar mechanism to help us retain our sense of balance. When alcohol mixes, poorly, with the water in our ears, it mucks up the works, thus that unfortunate spinning sensation This book offers a cornucopia of gee-whiz explanations just like those.

Shubin shows how our genetic makeup makes us high-end mutts, the product of eons of accumulated changes, a creature designed by a committee. That baggage can get heavy at times. Elements of our makeup that made sense when we were hunter gatherers now leave us ill-prepared for sedentary life in the 21st century.

Shubin has a gift for popular science writing. He says that he was “trying to understand the family tree of relatedness.” Clearly, he succeeded. There were only one or two times in the book when I felt at all strained. And his effervescent enthusiasm for his field is infectious. If I were a student, I would be offering bribes to anyone who could help get me into his class.

My only gripe about this book is that it was too short.


PS - I came across a few items while looking into the book that are worthwhile.

There is a nice interview with Shubin at http://bloggingheads.tv/diavlogs/8008. It runs about 51 minutes and was never boring. Another is http://tiktaalik.uchicago.edu/, which offers detail about Tiktaalik.