Getting to know ‘your inner fish’: Shubin reveals an evolutionary journey of the human body

Paleontologist Neil Shubin unites the discoveries of fossils and the sciences of paleontology and genetics with his experience of teaching human anatomy into a written voyage of evolution, titled Your Inner Fish: A Journey Into the 3.5-Billion-Year History of the Human Body.

“The best road maps to human bodies lie in the bodies of other animals,” Shubin writes in his new book, which was released Tuesday, Jan. 15. “The reason is that the bodies of these creatures are often simpler versions of ours.”

In Your Inner Fish, Shubin, Professor and Associate Dean of Organismal and Evolutionary Biology, and provost of the Field Museum, uses new fossil finds, genetic discoveries and animal anatomy to trace the origins of humans and the evolution of different body parts, such as limbs, teeth, skulls, ears and eyes. He explains how everything that is apparently unique about humans is built from parts that are shared with other creatures.

“I was hooked from the first chapter,” writes paleoanthropologist Don Johanson (Ph.D.’74), Director of the Institute of Human Origins at Arizona State University and co-discoverer of Lucy. “Creationists will want this book banned because it presents irrefutable evidence for a transitional creature that set the stage for the journey from sea to land. This engaging book combines the excitement of discovery with the rigors of great scholarship to provide a convincing case of evolution from fish to man.”

In 2006, the public was overwhelmed with news on the discovery of Tiktaalik roseae, a fossil “fishapod” that represents the transition between fish and four-legged animals, known as tetrapods. This finding “gave us powerful new insights into the invasion of land by fish over 375 million years ago,” said Shubin, one of the fossil discoverers. This finding was his impetus to write the book.

Shubin explains why fossils are one of the major lines of evidence to understand the human body. As one example, he uses Tiktaalik roseae, which, besides its fish-like features, had a skull, a neck, ribs and parts of limbs similar to land animals.

“In this extraordinary book, Neil Shubin takes us on an epic expedition to Arctic wastelands, where his team discovered amazing new fossil evidence of creatures that bridge the gap between fish and land-living animals,” said biologist and author Mike Novacek, senior vice president and provost of science at the American Museum of Natural History.

“Ancient fish bones,” Shubin writes, “can be a path to knowledge about who we are and how we got that way. We learn about our own bodies in seemingly bizarre places, ranging from the fossils of worms and fish recovered from rocks from around the world to the DNA in virtually every animal alive on earth today.”

While a graduate student at Harvard University, Shubin realized that fish, frog and chicken embryos looked alike and that there is a common architecture within all of them. For example, a fish and a human look identical for weeks after fertilization.

“All of our extraordinary capabilities arose from basic components that evolved in ancient fish and other creatures,” Shubin writes. “We are not separate from the rest of the living world; we are part of it, down to our bones and even our genes.”

Humans can map their evolutionary history through DNA, he explains. How the human body is built is written in its genetic code, and scientists can compare that code with those of creatures as different as flies and fish. For example, appendages, such as wings, fins or limbs, are built by similar types of genes. The transformation of fins into limbs did not involve the origin of new genes, but rather, ancient ones—such as those involved in fin development—were used in novel ways to make limbs with fingers and toes.

Additionally, scientists turned to creatures such as flies, worms, yeasts, mice and even microbes to better understand diseases. Shubin suggests that many leading causes of death in humans—heart disease, diabetes, obesity and stroke—have a genetic basis and probably an evolutionary one as well. During their evolutionary history as fish, amphibians, reptiles and mammals, human ancestors were active predators or active collectors and tree-living animals. With the illnesses that humans suffer today, “much of the difficulty is almost certainly due to our having a body built for an active animal but the lifestyle of a spud,” he writes.

Shubin tells this story not only to the scientist, but also to the lay reader. His message is the same: “I can imagine few things more beautiful or intellectually profound than finding the basis for our humanity,” he writes, “and remedies for many of the ills we suffer, nestled inside some of the most humble creatures that have ever lived on our planet.”

Shubin will lecture about his book at 2 p.m. Saturday, Jan. 26, in Montgomery Ward Hall at the Field Museum. The lecture is free with basic admission to the museum.

The book will be available for sale outside the lecture hall before and after the presentation, as well, and Shubin is scheduled to sign books following the lecture.

(Maja Fiket contributed to this story.)