Classroom Pass is an Iowa Now project that sent teams of writers, photographers, and videographers to 15 classes on Wednesday, Oct. 22, to showcase the breadth and strength of the University of Iowa's academic offerings for undergraduates as well as its dynamic faculty and state-of-the-art facilities. See what other classes they visited.

Class: Age of Dinosaurs
Instructor: Christopher Brochu, associate professor of Earth and environmental sciences

Christopher Brochu strides into the Pomerantz Center auditorium with a resin replica of a five-foot-long jawbone tucked under his arm. He sets it down carefully on a table adjacent to the podium, attaches a microphone to his shirt, looks up at the 100–plus students watching him, and grins. Today’s lesson in Age of Dinosaurs: tyrannosaurs.

Tyrannosaurus rex, Brochu points out, is one of only two species popularly known by its scientific name (the other is E. coli). Everyone is familiar with the giant bipedal dinosaur, which has been depicted frequently in the media since its discovery more than 100 years ago. Millions have flocked to get a glimpse of Sue, a T. rex fossil specimen on display at the Field Museum of Natural History in Chicago (and whose left jawbone is replicated next to Brochu).

Much has been learned about tyrannosaurs in the last decade alone, and Brochu reviews the facts. Much also has been debated—some paleontologists, he divulges, are not above making sensational claims to gain attention. However, the fossil discovery 10 years ago of Dilong, believed to be a smaller ancestor of T. rex, suggested the very real possibility that T. rex had feathers: the fossil, Brochu explains, revealed “carbonized fluff.”

Other mysteries big and small still surround the dinosaur: How did it get so large? Why were its arms so small? What caused the holes in Sue’s lower jaw?

“It’s an exciting time to be working on tyrannosauroids,” Brochu says. The detective work will continue…