In the late 1960s, Curator Emeritus Niles Eldredge was a graduate student with a passion for trilobite eyes. He had been taught to expect slow and steady change among the Devonian arthropods he collected. Only his trilobites were doing one of two things: staying the same, or evolving in leaps. Several years later, Eldredge, along with Stephen Jay Gould, turned his observations into a theory known as “punctuated equilibria”: the idea that species stay relatively the same, throughout the fossil record save for rare bursts of evolutionary change.