Students arrived in class employing nearly as many misconceptions in their explanations of evolutionary change as they did key concepts. In addition, while it is deeply worrying that 70 percent of students employed misconceptions in their Evolutionary explanations, it is even more alarming that remarkably diverse assemblages of misconceptions (n > 4) were present in 40 percent of students (see also Bishop and Anderson 1990). It should be of great concern that only 30 percent of biology majors in the active-learning group (and 14 percent in the postcourse comparison group) lacked misconceptions postcourse.