Dr. Linde Eyster has just received delicate cargo. Seven living sea urchins—three “girls” and four “boys”—have arrived on campus from Florida, which means that Dr. Eyster’s Advanced Biology students can now get to work.
After prepping the living specimens, students begin the favorite “urchin lab.” This foundational, hands-on experience gives students a conceptual, visual, and mechanical insight into the core content of their course: learning about biodiversity and development of plants and animals.
“This is the best batch of sea urchins we’ve had in years,” says Dr. Eyster as the class induces the urchins to release their mature eggs and sperm. The students, split into teams, rinse the eggs, dilute the sperm, and then study the fertilization process under microscopes. Dr. Eyster projects a slide onto the television, and the class gathers to see a magnified version of a fertilization envelope forming around a zygote. “That is so cool,” a student says.
These early events happen rapidly; to get the full experience students will spend many of the following 24 hours (with time out for eating and sleeping) in the lab. As the embryo development progresses, one of the biggest challenges for students is learning to use a pipette to catch one of the tiny, swimming larvae and transfer it—in a small drop of water—onto a depression slide for observation under a microscope. The students will create drawings by hand and record development stages using the microscopes’ digital cameras. Students record developmental markers, answering questions like, “How long did it take to get to stage X or stage Y?” They will follow the development of the larvae for three to four weeks.
“This lab experience grounds students in many of the topics we will consider throughout the year,” says Dr. Eyster. “From the parts of a cell through how global climate change might affect specific organisms.”