A journey into the 3.5 billion year history of the human body
by Neil Shubin

“So here is the trick to designing a new fossil expedition: find rocks that are of the right age, of the right type (sedimentary), and well exposed, and we are in business.”

This is a nonfiction science book by American paleontologist and evolutionary biologist Neil Shubin. Shubin shows the reader how our body reveal an evolutionary kinship with all other organisms on the planet. The author has taught anatomy for future physicians and it turns out that being a fish paleontologist is a powerful way of doing just that. Because all amphibians, reptile, birds and mammals are descendants of ancient fish.

Shubin uses a walk through a zoo to show the reader the commonalities between organisms. The bones in our limbs are connected in the following way; one bone, two bones, lots of bones, five bones. In our arm that would be the upper arm, lower arm, wrist and hand. It has been known for a long time that mammals, birds, amphibians and dinosaurs also share this feature. As well as jaws, heads and the general body plan. Shubin does a great job uncovering many more similarities between the bodies of different animals.

“When you see these deep similarities among different organs and bodies, you begin to recognize that the diverse inhabitants of our world are just variations on a theme.” 

In addition to general science of our evolutionary past we get to know a about how Shubin and his team found Tiktaalik. This name should ring a bell because it was a monumental discovery that literally showed a transitional fossil between fish and us tetrapods (four legged animals). The expeditions to Ellesmere Island in northern Canada is a very interesting read. He relates some funny stories such as the time they mistook an arctic hare for a polar bear. Before you laugh too much by that story, remember that we are all descendants of primates who were really skilled at avoiding predators.

By showing us how evolution works like a tinkerer, to put it in the words by François Jacob, Shubin also takes a jab at creationists and others who wants to discredit evolution and the process of natural selection. There is very little intelligent about why we men develop hernias because our spermatic cords, inherited from ancient fish ancestors, weaken the wall of our stomachs. Or how our larynx makes us vulnerable to choking. The fun part for me was how our hiccups is a remnant of how amphibians use their gills. They use the same nerve signals for breathing as we do when they misfire in our bodies. So the next time you have hiccups think of your inner tadpole. Another interesting gem is that we mammals have about 1000 genes related to the sense of smell. In humans, however, about 300 of them are rendered useless by mutations. But we still carry them. Surely if some sort of celestial engineer designed the body we wouldn’t have lots of disabled genes like that.

Your Inner Fish is easy to read and is an excellent explanation of the evolutionary process and the traces it leaves behind. The arguments are detailed and precise without being too difficult to follow. Shubin presents a thorough interconnected story of paleontology, embryology and developmental biology. Not to mention An excellent description of how the scientific method should work. A hypothesis predict certain things that can be tested, such as the location and time period when fish crawled up on land. This is also confirmed by findings in the field or by experiment. Which is precisely how Shubin and his team found Tiktaalik. Ellesmere Island is made up by sedimentary rock from the expected time period (Devonian).

“This fossil confirmed a prediction of paleontology: not only was the new fish an intermediate between two different kinds of animal, but we had found it also in the right time periond in earth’s history and in the right ancient environment.”

I highly recommend this book to anyone interesting in the history of life and how we humans fit into the larger picture. All life (on Earth mind you) is related and knowing that should inspire us to take better care of our little planet.

knowing something about the deep origins of humanity only adds to the remarkable fact of our existence: all of our extraordinary capabilities arose from basic components that evolved in ancient fish and other creatures.

I first learned about this book when I stumbled across the documentary series. The documentary is divided into three episodes titled Your Inner Fish, Your Inner Reptile and Your Inner Primate. I highly recommend that one too. You can find it on youtube.

If you only read one chapter of this book it should be the last one. It is titled The Meaning of it All, and has the following aweinspiring quote;

If you know how to look, our body becomes a time capsule that, when opened, tells of critical moments in the history of our planet and of a distant past in ancient oceans, streams, and forests… This history is our inheritance, one that affects our lives today and will do so in the future.

Rating 6/6

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