Out of the Classroom and Into the Field

Students in Rachel Merz's class in the field, examining an oyster community and looking at sponges, corals, crabs, and snails.

"Fiddler crabs are really charming animals," declares biologist Rachel Merz, the Walter Kemp Professor in the Natural Sciences at Swarthmore. Her affection for these busy invertebrates is apparent as she describes their feeding mechanisms and sexual dimorphism: While the females have two similar-sized small claws for feeding, the males have a small claw and a gigantic claw, the latter used for sexual display and for battling other males.

Merz reels off sample questions that students in her Marine Biology class (taught every other fall) might investigate after reading scientific papers about the crabs: How long does it take a male to feed if it has half the feeding equipment but twice the mass of the female? How does this affect its locomotion? In what ways does it escape predation? Do males and females have different digestive efficiencies? In groups of three or four, students choose a question, design an experiment and then head out to the salt marshes in Delaware to collect the animals. "That's a hysterical trip," Merz says, "because it's ... a great equalizer. There's nobody who's really graceful or lovely in the mud."

Authentic field experiences

Merz says she strives to give students an "as authentic and engaging an experience of the field as I can." She goes on to say that she wants them to learn how a biologist thinks and what it's like to make a discovery. Merz feels fortunate to have outstanding students who are "unfettered by convention," arriving at the College eager to have new experiences and enrolling in her courses out of interest, not requirement. She notes that in addition to the students' intellectual abilities and maturity, Swarthmore has small class sizes and good resources, creating an excellent environment for biological study. "Many students ... have never had the whole experience of thinking about the biology of an organism, then going and actually getting it in the wild and bringing it back and studying it. Then they do these experiments, some of which go as planned and many of which do not, but that's the authentic part," she observes wryly.

During fall break, Merz took interested students in her Invertebrate Biology class to the Duke University Marine Labs in Beaufort, N.C., to collect animals in different habitats and study them in the lab. Examining the invertebrates proved to be such an absorbing group passion that it inspired an alumna working with them, a current graduate student at Duke, to exclaim, "This is totally Swarthmore! You get into books and animals and each other, and everyone's happy."

Merz's Invertebrate Biology course focuses on examining the animals in different habitats. This year, the class went to Cape Henlopen in Delaware and investigated a variety of habitats, including mud flats, the outer coast, and the bay. Later in the semester, the students traveled to a Pennsylvania state park to search for easy-to-find fossils, another novel experience for many. The class is also planning a visit to Philadelphia's Academy of Natural Sciences to see the invertebrate displays there. These trips, along with another marine biology excursion to Belmar, N.J., in which the students study the organisms found at various intertidal zones (areas exposed by the tide), illustrate the range of the immersion experience that Merz provides. Students have ample opportunity to observe the invertebrates both in the field and in a lab, to study how people work with them, and to explore a professional invertebrate collection.

Watching students become biologists

Her course in biomechanics is less field-trip-based, but Merz helps students travel to their own field sites if their self-designed projects require it. She also facilitates student participation in summer research by overseeing applications for field funding, which is readily available. Some students work with faculty at the College, some faculty take students with them in the field, and some students are funded to work in labs that aren't associated with the College. "We like to think we span biology but we don't cover biology," says Merz. "It's important to have ways for students to have experiences beyond what we can offer them, so there are funds for that, too." Most recently, for instance, one student has been doing research in Africa on hyenas, another worked in Germany, and others were based in field stations in Virginia and Washington state.

Adam Hardy '12, a talented young biologist with whom Merz has worked extensively, originally began a project with others in Merz's Biomechanics course examining how the sand dollar rights itself after being inverted in the surf. "It's a very elegant little study," says Merz. "It's got a good specific question that clearly makes you puzzled: How could something that's built like a dinner plate turn itself over?"  Using a flow tank at the College, he discovered that the shell, which is asymmetrical, rotates itself into a position in relation to the direction and velocity of water that makes it more likely to flip back. Hardy obtained summer funding to continue this inquiry on a different species at Friday Harbor Laboratories in Washington state, where Merz also worked, and the behavior was replicated. Now Hardy and Merz are in the final stages of publishing a paper on this research, which has been accepted and will be published in early 2013.

Merz takes great pleasure in watching her students develop over four years ("students all get better!") and then maintaining many of those relationships after graduation. Every January, when the National Society for Integrative and Comparative Biology meets, she looks forward to a Swarthmore lunch. It's a chance for students to envision their futures by meeting recent grads, postdocs, and faculty who have advanced further in biology. "And they are so good to each other," she adds.

"I've come to believe I was born a biologist," says Merz, whose enthusiasm for her subject is infectious. Many of her early memories involve finding bugs in her yard in New Mexico and doing her own version of experiments. But the real epiphany occurred when the 9-year-old future scientist reacted to her first view of the ocean: "This is the neatest thing I've ever seen! I'm doing this!" And so she has.