Theoretically, organisational culture, instructor training, and learning space design influence how faculty teach STEM courses. Previous studies have used classroom observation protocols to characterise the range of teaching practices in mostly teacher-centered, traditional STEM classrooms. In this study, we examined the classroom behaviour of 13 STEM faculty teaching biology courses in a reformed undergraduate STEM learning environment. Our findings indicate that instructors teaching in this reformed environment guided student learning (58.4 [plus or minus] 1.9%) almost three times more than they presented information (20.0 [plus or minus] 2.2%). Students worked individually or in groups and talked to the whole class (57.1 [plus or minus] 1.8%) 1.5 times more than they received information (35.5 [plus or minus] 1.9%). We found significant positive correlation between 'instructor presenting' and 'students receiving' information (r = 0.743, p = 1.4 × 10[superscript -4]) and 'instructor guiding' and 'student working and talking' in class (r = 0.605, p = 7.2 × 10[superscript -5]), suggesting that instructors can change their own classroom behaviours and expect concurrent change in their students' behaviours. Finally, sequencing teaching practices in high active-engagement classrooms showed instructors move and guide student group work and lead whole class discussions before lecturing to students, which could lead to deeper learning of conceptual knowledge. We discuss insights from these findings that have implications for acculturating evidence-based teaching practices in STEM departments.