Culture Exchanges

Your Inner Fish and the Nature of Science

The Tiktaalik fish and how evolutionary biologists do their research.

Book Reviewed
Your Inner Fish: The Amazing Discovery Of Our 375-Million-Year-Old Ancestor. By Neil Shubin. Pantheon Books, New York 2008.

By Samiksha Neroorkar

Your Inner Fish is the story of evolution told by a palaeontologist cum evolutionary biologist, Neil Shubin. Shubin earned a PhD in organismic and evolutionary biology from Harvard University in 1987. He is currently the Associate Dean of Organismal Biology and Anatomy and Professor on the Committee of Evolutionary Biology at the University of Chicago. The book provides a fresh perspective on evolution by presenting new evidence and many fantastic facts which can be easily understood by the lay reader. 

The book begins with an account of the discovery of the fossil fish Tiktaalik in an expedition by Shubin and his team to the Ellesmere island in the Arctic. This extinct fish belongs to the late Devonian period and lived on Earth about 375 million years ago. Tiktaalik is classified as a fish because it had gills and scales. However, its head resembles a crocodile’s with nostril-like openings and its fins have wrist-like bones which could have been used to support its body in shallow water, like four-legged animals. These and other characteristics make Tiktaalik an important evolutionary link between fish and land animals. 

The book goes on to explain the evolution of the human body by tracing the origin of different body components like genes, limbs, skull, eyes and skeletal frames to their ancestors. In this process of unearthing our evolutionary tree, Shubin shows us how there is an entire zoo inside our body. From headless worms to hairy polar bears, we share characteristics with nearly every living being on earth. The explanation of why the human body functions in a certain way can be found within an organism somewhere on this planet. For instance two genes, responsible for hearing and vision separately in man, are combined in a mosaic fashion into a single primitive gene responsible for the development of 20 odd eyes in the box jellyfish. Another example is that the layers of the human embryo and the chick embryo share many characteristics. 

Book cover

Your Inner Fish makes several references to the tenets of the nature of science(1). First, scientific knowledge is based on empirical evidence derived from the observation of the natural world and not just laboratory work. The book explains how paleontologists and evolutionary biologists make predictions about the history of life on earth and then go about looking for fossils, footprints, and other evidence. At the same time, they conduct experiments in the laboratory that will help them understand the structure and functioning of current organisms. Second, science does not have all the answers. The information that paleontologists and evolutionary biologists gather is synthesized into a whole which might or might not substantiate their hypothesis. In cases when the evidence is ambiguous, they use statistics to arrive at conclusions. Many times they let their prediction stay as a ‘working hypothesis’ until definite data comes along to prove or disprove it. In some cases, especially that of humans, very little experimentation of this kind is possible. Then, the evolutionary biologists work with other organisms (chicks or sharks) and the results are established as ‘truth’ for humans too. This also helps to understand two more tenets of the nature of science. One that scientific knowledge is tentative. The other is that laws and theories are related yet distinct entities and individually important kinds of scientific knowledge. 

The book also strongly brings out the relationship between science and technology. The reliance on technology like DNA sequencing labs, computers, imaging, and radiographic devices is apparent in the many experiments described in the book. It explains how these advances have helped scientists see evidence in a different light in recent times. The socio-cultural aspects of science are also evident in this book. The fossil fish was discovered in the Nunavut Territory of the Arctic. Shubin and his teammates wanted the name to embody the origin of the fossil and also show their gratitude to the locals for letting them work there. The fossil was named Tiktaalik meaning “large freshwater fish” by the Inuit people of the Nunavut territory. Another socio-cultural aspect is the collaboration that comes up through the expeditions and the coordinated experiments conducted in different laboratories which help develop the results. Finally, the tenet that science is creative is brought out by Shubin’s colorful account of the process of evolution. His love for the subject is evident in the way he describes the first time he saw the internal mechanism of a dissected human hand or his discovery of the rodent jaw fossil-bearing similarities to the human jaw. Science is not dry and emotionless but beautiful, overwhelming and powerful all at the same time.

Your Inner Fish is a highly engaging compact revelation of scientific facts that leaves us amazed at the beauty of our system and how it has come to be. Filled with illustrations and photographs, lucid explanations, a dash of humor and a personal touch, Shubin simplifies the process of evolution. In his own words, he makes us want to “continue asking questions and seeking answers to the unknown.”

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Footnotes

1. Nature of science is the set of attributes and values of the science subject. Some of the basic tenets of the nature of science are that scientific knowledge is empirical and tentative, there is not a standard scientific method, science and technology are not the same, but they impact each other, science involves creativity, science is influenced by historical, social and cultural aspects and that laws and theories are two distinct products of science.  

Cover photo: Tiktaalik fish restoration. Obsidian Soul / Creative Commons BY. Edited by Thea Pan.

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About the Author:

Samiksha Neroorkar has recently completed her doctoral studies in education from Tata Institute of Social Sciences. She works in the area of Vocational Education and STEM education research.

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