Issues surrounding evolution education in the U.S are of key importance to biology educators. Little research has been published measuring the understanding of and attitude toward evolution held by biology majors in the university education system. The goal of this research was to investigate the understanding and attitude toward biological evolution of particular Iowa State University students, while simultaneously detecting any change over time due to instruction. The survey used both quantitative and qualitative measures to determine students' understanding and attitude. The results show that students' understanding of particular evolutionary concepts does improve with instruction, while only some measures of attitude toward evolution improved. Students were more likely to accept non-human evolution after instruction, but no more likely to accept human evolution. Additionally, students did not significantly change their theistic view after instruction. Nature of Science issues were also measured, and student understanding of the NOS did improve with instruction.