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May-June 2008
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< previous | 1 | 1 | 2 | 3 Fast-forward to July 2004. With grant money running out, and the prognosis looking poor, Shubin and Daeschler opted for a fourth and final trip (their third to Ellesmere). Shubin describes cracking ice and rock in the bottom of a quarry one day when he saw a patch of fossilized scales and a jaw-like “blob” in ice unlike any fish mouth he’d ever seen. The next day, while foraging at the top of the same quarry, Shubin’s colleague and former fellow graduate student Stephen Gatesy, Ph.D. ’89 (now a biology professor at Brown), dug out a piece of rock and “we realized we saw a flat-headed something, something unknown,” Shubin reports. “It was a snout sticking straight out from the rock.” The team spent the rest of the summer painstakingly chipping away at the rock around the creature so they could wrap up the boulder-cum-fossil and transport it thousands of miles to the lab where, for two months, preparers used dental tools to pick apart the specimen. What was revealed was a creature with eyes on top of its flat head, a neck, upper arm bones, a wrist, parts of a palm, and “an elbow joint that Tiktaalik would’ve used to push itself up off the substrate, as if it were doing push-ups,” Shubin explains. “And it had ribs—larger and more expandable ribs than you’d ever see on a fish.” In short, “Tiktaalik is not a random find,” he says. “It is a piece of the human story.” To date, the core research team has found about 20 individuals—based on isolated fins, jaws, and other pieces—but only about four really good specimens. “We’re the only people working up there and we’re going back this summer, in July, in hopes of finding more bones,” Shubin says. “You never know what’s going to happen when you get there, because of the weather, but the goal is to go to the original site and work on new areas around it” to find slightly younger or slightly older rocks and see if any bones they contain shed light on further developmental changes. The group has found other water-based creatures—some “really bizarre-looking” armored fish, some eight- or nine-foot-long predatory fish, and some fish as tiny as a fingernail. Shubin is excited that the Tiktaalik find has also inspired other scientists, who are looking at new, undisclosed geological locations for more Late Devonian specimens. “We are beginning to unlock the mechanisms that underlie evolutionary change, so we can ask what is the genetic and developmental recipe that built the human, and how is it different from fish?” he says. “We’re at a moment in scientific discovery where we can begin to see that that kind of understanding is possible within our lifetimes, that the basic tool kit and developmental processes are very ancient—that a version of same tool kit that builds a worm builds a human. It’s been a remarkable time for paleontology, a very powerful revolution on a lot of scientific fronts.” After his talk at Harvard Book Store, the audience asked Shubin questions that ranged from specifics about Tiktaalik’s anatomy to his arctic experiences and plans for the future, to his views on intelligent design and creationism. Did he think his discovery would sway religious beliefs? What should teachers say about Tiktaalik—how is it a scientific tool for students? “No degree of evidence will shift the views of a creationist, ” Shubin responded, then added with a laugh, “but if, next to my Tiktaalik, I’d found a human skull, then that would be truly devastating” to evolutionists. What about intelligent design? “I don’t have time for it because it’s not testable, it’s not science,” Shubin explained. “I have a job to do and that’s making hypotheses and going out in the field and finding out if they are true. I became a scientist because I like looking at creatures and discovering new things that tell us about the history of life.” ~Nell Porter Brown  
 
 
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