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Original EssaysConnectionsby Neil Shubin
My first encounter with the intellectual beauty of anatomy didn't happen in the field or the laboratory; it took place in the rare book room at the library. During my first months in graduate school, I decided to look at some of the original volumes of the classic tomes in my field. The university's library had a fairly open policy with regard to viewing rare books so I was able to dig out papers, monographs, and memoirs written by the greats in my field. One of the first I opened was On the Nature of Limbs written by the famed British anatomist Sir Richard Owen in 1859. Embedded in the middle of the text was a single drawing that set me off on the path that was to define my scientific research for the next twenty years. It was a foldout print, about four pages wide, that took a bit of work to open without damaging the book. I remember carefully exposing the folds of the yellowed paper to find a gorgeous lithograph depicting images of the skeletons of humans, birds, and reptiles. The take-home message of this diagram was as elegant as it was simple: creatures as different as birds, bats, and people may not look much alike, but their bodies share a common architecture. Owen showed that the pattern of upper arm, forearm, wrist, and finger bones was largely the same in bird wings, whale flippers, and human arms. That is, whether used to swim, fly, dig, or throw a baseball, all limbs share a common design. Owen's insight was that we animals are variations on a theme, and my job became to understand how this theme arose in the first place. Could we trace Owen's beautiful architectural design back in time to more primitive creatures that do not have limbs at all? After that early encounter with Owen, much of my time has been spent looking under the microscope at embryos, dissecting animals in the anatomy laboratory, and digging for fossils. At first blush, it is hard to imagine a common thread to these different experiences, yet it is in these arenas where we discover our deep connection to the rest of life on our planet. Embryos show us the ways that bodies are built in each generation, the biological rules and tools that build bodies from a single cell. Anatomy, particularly comparative anatomy, reveals how organs of diverse species differ from one another. And, significantly for me, fossils reveal the ways that different bodies were assembled during evolutionary time. It was here, in the search for fossils, where I truly became a science addict. You never forget the first time you find a fossil. There is a special feel to the whole experience because you know you are the first person on the entire planet to see the thing. It is even better when this fossil tells us something new about evolution or the history of our planet. The first fossils I found back in graduate school were small 200-million-year-old mouse-like creatures that gave us a new insight into how mammals evolved their distinctive ways of chewing. It was the immediacy of finding fossils that really hooked me: somehow by cracking rocks I could find an object that gives us knowledge about our world and our bodies. To a great extent, this kind discovery is the thrill of field paleontology. As I've come to learn, field paleontologists spend a lot more time not discovering than discovering. My branch of expeditionary paleontology is one where my colleagues and I try to find whole new sites for fossils, usually in places where people haven't looked before. The failure rate for this kind of work is very high, but we've had a few successes that have kept us in business. Because of these challenges, virtually every expedition has changed me, often because I've had to adapt to something new to get through the experience. It has gotten to the point where, before I depart on each new trip, I ask myself what will I learn about our world or about myself? Early on, when I was a budding field paleontologist, the lesson was patience. In our hunt for fossils, we typically set down on an area that has lots of exposed rock for us to work. The best rocks are those that haven't been covered by dirt, vegetation, or human settlements. Then, after setting up camp and making everything secure, we set off walking and looking for bones at the surface, often for weeks at a time. We spend most of our time not finding anything, and for a novice field worker, this is the toughest lesson. The best paleontologists learn to maintain intense concentration on the rocks through long days of seeing nothing. Even whole field seasons can be utter failures. In these cases, the toughest call is deciding when to quit and when to persevere. In our most recent venture, it took my colleagues and I four summers spread over six years to find what we were looking for in the Canadian Arctic. We were led up North because Canadian geologists mapped what appeared to be ideal rocks to find evidence of the transition between fish and land living animal. We walked hundreds of miles over these 375-million-year-old rocks to find fossil fish. We spent the equivalent of months looking at barren rock, often freezing in the process. Then, in 2004, the whole bet paid off: we found a beautiful fish that had many features of very primitive land-living animals. It was seeing the bones of the fin of this fish for the first time that really made me pause. Here, in the Devonian-age rocks of Ellesmere Island, we found a fish that had parts of Owen's limb architecture inside it. Owen's grand design for the skeleton of limbs had its roots in ancient fish. And not just any fish — a fish that had a whole suite of features from skull to jaw that links it to amphibians. People like Richard Owen, and later Charles Darwin, gave us the intellectual tools to see how fish bones can tell us about the basic structure of our bodies. That insight led my colleagues and me to dig in the rocks of the Arctic. It guides others who look at the embryos of sponges, worms, and fish. What we see lying inside ancient rocks and inside these embryos is almost a mirror of ourselves. Here, in these humble places, we discover how our humanity, with all its uniqueness, has emerged from parts common to the rest of life on our planet.
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Neil Shubin is provost of The Field Museum as well as a professor of anatomy at the University of Chicago, where he also serves as an associate dean. Educated at Columbia, Harvard, and the University of California at Berkeley, he lives in Chicago.
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