There is a tendency for lecture-based instruction in large introductory science courses to strongly focus on the delivery of discipline-specific technical terminology and fundamental concepts, sometimes to the detriment of opportunities for application of learned knowledge in evidence-based critical-thinking activities. We sought to improve student performance on evidence-based critical-thinking tasks through the implementation of peer learning and problem-based learning tutorial activities. Small-group discussions and associated learning activities were used to facilitate deeper learning through the application of new knowledge. Student performance was assessed using critical-thinking essay assignments and a final course exam, and student satisfaction with tutorial activities was monitored using online surveys. Overall, students expressed satisfaction with the small-group-discussion-based tutorial activities (mean score 7.5/10). Improved critical thinking was evidenced by improved student performance on essay assignments during the semester, as well as a 25% increase in mean student scores on the final course exam compared to previous years. These results demonstrate that repeated knowledge application practice can improve student learning in large introductory-level science courses.