Grades in introductory STEM courses can impact intrinsic motivation (IM) and self-efficacy (SE). We used an exploratory approach to examine trends in grades and how IM and SE impact students' grades. It is known that most first-generation (FG) college students are from underrepresented backgrounds (URM), and that these students are least likely to persist in STEM fields. Therefore, gaining a better understanding of motivation in our most underserved students could be critical to improving their success in introductory biology courses and ultimately future persistence in STEM. We found that, on average, URM FG students received the lowest final grades and experienced the greatest declines in IM and SE. This research informs the way we may think about changes in motivation and self-efficacy in our introductory biology courses as these lay the foundation for future learning and success.