Holding a long syringe, Pam Miller injects potassium chloride into the soft tissue around the mouth of a purple sea urchin. Within minutes, the animal’s gonads contract and begin to expel gametes—eggs in this case, since it’s a female. The high school biology teacher sets the little urchin on a beaker and watches as she sheds her eggs into the seawater, in cloud after filmy cloud.
Depositing a droplet of eggs onto a glass slide, Miller places it under a microscope, at 40x power. And then the drama really begins. When sperm from a male sea urchin are added to the slide, they swarm around each egg like agitated gnats. Bubble rings quickly encircle the eggs, indicating that fertilization has taken place—right before our eyes.
“Live urchins are a wonderful material,” says David Epel, associate director of Stanford’s Hopkins Marine Station, who works with Miller to design high school curricula using the spiny creatures. “You don’t have to learn a lot of complicated lab techniques, which makes them very good for inquiry-based education.”
Easily fertilized and relatively easy to maintain in salt-water aquaria, sea urchins have captivated researchers since the 1800s. They’re a favorite model organism for Epel, a professor of marine science and of cell and developmental biology who studies the increasing acidification of the ocean. Epel met Miller at a Hopkins open house in the early 1980s, where she got her first glimpse of the classroom potential of sea urchins. Epel ended up paying a visit to Miller’s second-year biology classes at Seaside High School, which begat return visits, which begat a long-standing professional collaboration. “The first National Science Foundation grant was funded because they showed how to take university research and apply it in a way that high schools could benefit,” says Chris Patton, a staff associate in Epel’s lab.
In 1998 Patton helped Epel, Miller and then postdoc Henrik Kibak design a NSF-funded, open-access website that received more than 10 million hits before 2001, when the University stopped counting. Intended to help high school teachers conduct live labs, the site walks them through experiments in which students can look at developing sea urchin blastulas and embryos—and ask their own questions. “The secret is for them to understand what science really is by knowing that the investigator is in charge of directing the inquiry, and that the scientific method leads them to conclusions they can draw for themselves,” says Miller, who in 2001 received a presidential award for excellence in math and science teaching.
Epel and Miller launched a new NSF-funded site in June that draws on their experience with sea urchins to construct virtual labs designed to teach core principles in biology, genetics, the environment and the scientific method. In the virtual core biology lab, students practice dragging the internal organs of male and female sea urchins to their correct positions and learn how gametes are produced. Another lab walks students through the basics of learning to calibrate a microscope. They can look at sand dollar larvae and blades of grass at various magnifications, and manipulate specimens by dragging them out of a slide box onto the microscope stage.
Miller says some of the virtual labs “do things we could never do in the classroom,” for lack of equipment or because key cell divisions would take place when students were not in class. Also, it can take five days to fertilize sea urchin eggs and watch them divide and develop into the larval stage—and all of that is just observational. “The object is to see real results from experiments they help set up.”
Epel says future labs will draw on doctoral projects in his Hopkins lab. “And we’re going to develop one virtual lab that reproduces an experiment that led to a Nobel Prize.”
