Review: Your Inner Fish by Neil Shubin

(“A nonfiction book” from the Reading Challenge)

I am switching my non-fiction book because I read this one more recently and feel that I can write a decent review. (I did read My Beloved Brontosaurus by Brian Switek, which was my original choice, and I definitely liked it a lot and would recommend it! But I didn’t get to writing a review as soon as I should have, so I’ll do this one instead.)

This book was a Christmas present from a family member, who rightly guessed that I would enjoy it. It was very good!

The author is a paleontologist and professor of anatomy, and he has a clear, engaging writing style that was very easy to read. The book is (as you might guess from the title) talking about evolution as it relates to the biology and anatomy of the human body.

I really loved the way he talks about science! He talks about his lab (which is half fossils and half genetics/DNA, apparently), and he talked about looking for fossils in ways that I hadn’t thought about before. He points out that while yes, there is a certain amount of luck involved in actually finding the fossils you’re looking for, you have to start by doing the right prep work identifying where your chances will be greatest.

He uses the example of wanting to find an intermediate stage between finned fish and amphibians with true limbs, a transition which happened between 385 and 365 million years ago. So, he had to identify rocks in that age range, of the right type to preserve fossils at all (meaning, sedimentary rocks), and that were somewhere exposed/accessible to people. In this case, Ellesmere Island in Canada, north of the Arctic Circle, turned out to be the best place, and so that is where he and his team have gone summer after summer. And, after many seasons, they did in fact find the kind of fossil they were looking for; Tiktaalik was a fish that had fins…but they were fins with bones in them, and bones in the same basic number/arrangement that we see in all limbed animals today.

He does a really good job of working the reader through a somewhat abstract idea (that we can trace our bodies/body parts/body construction back in time through evolution, as evidenced by both fossils and genetics), by providing several concrete examples that show this, and going through the process each time. Looking at our bodies this way helps to make sense of some things about us that seem confusing when you think about them by themselves. Hiccups, for example. Why do we get hiccups? Well, probably because our bodies are descended from amphibious creatures that needed to be able to switch back and forth between breathing with lungs in air and breathing with gills in water. The muscle/nerve combination that causes hiccups originally worked as a pausing mechanism that allowed for that switch…only we don’t need it anymore, so for us it’s just a leftover thing our bodies do that can be a nuisance.

All of his examples are really interesting like that. Going back to limbs, he points out that every vertebrate creature that has limbs has limb bones in the exact same combination: one upper bone, two lower bones, blobby bones in the “wrist,” and then rod-like bones that radiate from those (fingers/toes, for us). The exact shapes, lengths and configurations of these bones are very different in an alligator, a bat, and a human, but the same basic combination is there in all three animals. In another example, he talks about nerves in the human head, some of which are very complex and kind of confusing, because they do lots of different-seeming things. But when you look at them from a developmental view, they make perfect sense, because one nerve is connected to all the various parts of the head that form from one “gill arch” on the human embryo, and another nerve is connected to all the parts that form from another “gill arch,” and so on. (Those “gill arches” are so called because, in fish like sharks, they do actually form into gills. In humans, they are present when we are an embryo, but then develop into various parts of our face, jaw, neck, and throat.)

So it was a very interesting book! It falls into the category of “I sort of knew the basics of this (evolution and how it works),” but this book lays it out so much more specifically and with such fantastic examples that it just becomes much, much clearer in my head. Books like that are the best ones, for me. I definitely recommend this one to anyone interested in paleontology, science, evolution, or the history of life on earth. A fantastic read!

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