This paper reports Grade 12 students' biology learning during interactive teaching classes in 2001 in Taiwan. The researcher as teacher, working within an interpretive framework, set out to improve her senior high school student biology teaching and learning. An intervention based on a social constructivist view of learning was designed, implemented and evaluated. The findings of this study indicate that intervention students' cognitive development was facilitated, their reasoning and social abilities were enhanced, and they enjoyed the lessons more. Their first term examination outcomes were comparable with those in the traditional teaching classes. This study, therefore, provides an example for how interactive teaching, based on a social constructivist view of learning, can be effectively used for teaching and learning biology in the senior high school in Taiwan.