Body Talk

 

Nov|Dec 08 Contents
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“Let’s compare Einstein to a fish,” paleontologist Neil Shubin said to the Class of 2012, projecting images of the physicist and a purplish beast of the deep onto a screen in Irvine Auditorium.

“But why stop at a fish?” he added a few moments later. “Let’s take it further back.” Like, all the way to an eyeless, comma-sized worm. Or still further, to an organism comprised of a single cell.

Shubin’s audience had already had the summer to acquaint themselves with this roundabout approach to human anatomy. The latest installment of the Penn Reading Project—now in its 18th year, making it as old as many of this year’s participants—focused on Shubin’s new book, Your Inner Fish: A Journey Through the 3.5-Billion-Year History of the Human Body.

Considering that homo sapiens came into being no more than 200 million years ago, it may seem a little odd to trace the history of our body back to an epoch when microbes were the biggest critters in the primordial pool. But the long view comes naturally to Shubin, who made headlines in 2006 for finding a fossil that filled a crucial gap in the transition of animal life from sea to land about 375 million years ago.
Tiktaalik, as that ancient tetrapod was dubbed, had fins containing primitive wrist bones capable of bearing weight. Unlike fish but like amphibians—and Albert Einstein—the animal also had a mobile neck. (Eight years before, while still at Penn, Shubin had unearthed a related fossil called Sauripterus [“Gazetteer,” March 1998].)

“To change from a fish to an amphibian means much of the body had to change,” Shubin remarked in his lecture, which took place the weekend before convocation (see next story). “But this is not just any random piece of evolutionary history. This is actually a piece of our own past as well. Because by understanding the fish-to-amphibian transition, and understanding the origin of limbs with fingers and toes, we’re understanding a piece of us.”

The simple act of hearing his lecture, Shubin remarked, reflected the long evolutionary process by which portions of reptilian jaw bones gradually changed shape and function to become the machinery of the mammalian inner ear.  And his ability to deliver the talk depended on his vocal cords, whose deep history reaches all the way back to the gills used by fish to breathe.

Your Inner Fish presents human anatomy as a synthesis of paleontology and developmental genetics, shifting deftly between the fossil record and cutting-edge embryology. “[F]rom so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved,” Charles Darwin wrote in the concluding sentence of On the Origin of Species. Shubin walks through some of the genetic and environmental mechanisms by which this occurs.

“If you know how to look,” he writes, “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. Changes in the ancient atmosphere are reflected in the molecules that allow our cells to cooperate to make bodies. The environment of ancient streams shaped the basic anatomy of our limbs. Our color vision and sense of smell has been molded by life in ancient forests and plains. And the list goes on.”

Shubin, who taught at Penn for several years, is currently a professor of biology and anatomy at the University of Chicago. Your Inner Fish was chosen for the Penn Reading Project in part to dovetail with the Year of Evolution, a citywide commemoration of Darwin’s 200th birthday in which the Penn Museum is playing a major part with an exhibit called “Surviving: The Body of Evidence” [“Fit Enough,” May|June 2008].

Janet Monge G’91, who co-curated that exhibit, joined Shubin on a discussion panel after the lecture. Scientists, she remarked, often find themselves at a loss when faced with the huge marketing efforts that have been coordinated by proponents of biblical literalism and Creationism in recent years. The Year of Evolution, in her view, is one way forward.
“The Creationism Museum was opened up in 2007, and they had 25 million visitors in the first nine months,” Monge said, referring to a controversial museum in Kentucky that portrays human beings and dinosaurs living in harmony, among other scenes that are contradicted by overwhelming scientific evidence. “We can’t compete with the funds, we can’t compete with the square footage, but we can compete in mental power—it’s just a matter of uniting and bringing our ideas not just to ourselves and people who read Science and Nature, but really to the world out there.”

Also on the panel was Peter Dodson, a professor in the School of Veterinary Medicine who introduced himself as a geologist, dinosaur paleontologist, evolutional biologist, veterinary anatomist, and “also a deeply committed Christian.”
“Many people have the impression that one has to make a choice: that one can either be a religious sympathizer or a scientist, but not both,” he said. “This is not true.”
Dodson pointed out that the theory of evolution by natural selection has been described by some thinkers as “Darwin’s gift to theology.”  It may be incompatible with a literal reading of Genesis, but then some of Christianity’s most influential figures—including Augustine of Hippo—were not biblical literalists.  Among Neil Shubin’s predecessors in the field of paleontology is Pierre Teilhard de Chardin, a Jesuit priest and paleontologist who participated in the discovery of the Peking Man fossil and developed a theology capable of accommodating Darwin’s insights.

At the end of his lecture, Shubin reiterated one of the overarching themes of his book and his profession. There is more than just majesty to the commonalities that human beings share with other creatures; our interrelatedness is also what makes the life sciences useful and productive.
“I like to think that if cures for cancer, and Alzheimer’s, and many of the ills that cause us pain and grief are discovered, they will in some way be due to work on flies and worms,” Shubin said. “I can imagine no better statement about the importance of our connection to the rest of life on this planet than that.” —T.P.

 


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  ©2008 The Pennsylvania Gazette
Last modified 11/04/08