Thomas Lord's constructivist college teaching methods (Lord, 1998; Lord, 2001; Lord, 2005; and Lord & Orkwiszewski, 2006) have changed my teaching of compulsory high school biology. My students have enjoyed some successes by moving away from teacher-centered classroom toward more constructivist learning environment, defined by Dufresne et al. (1996) as a set of beliefs about knowing and learning that emphasizes the active role of learners in constructing their own knowledge. For example, cooperative learning groups have replaced straight rows and the daily bell-ringer activity is no longer question about factoid the students had allegedly learned the day before. Now, at the beginning of each class, teams of three sophomores strive to solve biological problem about which they have very little background. Blank stares and recalcitrance remain persistent challenge, but participation usually increases as the course progresses and most students have responded favorably to these changes. However, we had not realized the dramatic improvements often reported at the college level (Burrowes, 2003; Wood, 2005). In accordance with constructivist philosophy, I have attempted to eliminate traditional lectures, as Wood (2005) successfully accomplished with her college students, but have found it to be particularly vexing challenge at the high school level. For instance, several years ago my students tried peer-teaching approach within each cooperative learning group in lieu of traditional lectures. Students became experts on small parts of the unit and then taught their topic to their team members. A few students created wonderful short lessons, but most morosely read the text aloud to their group, evidently encountering the strange words for the first time. We abandoned the experiment and returned to comfortable lectures, but broke them up with frequent small challenges embedded within the notes. For example, students might brainstorm five forms of evidence supporting evolution before copying notes on the topic. The notes also evolved to include printed version (omitting illustrations and key terminology) issued to each student. This facilitated students being able to listen to stories and examples while remaining engaged enough to fill in some important terminology. Regretfully, however, the method remained long way from the Thomas Lord student-centered constructivist approach that had so inspired me at several National Association of Biology Teachers conferences. Audience Response Systems (ARS) represent powerful new tool for increasing student engagement and I report here on my use of the technology to eliminate traditional lectures in high school biology. ARS technology (known variously as electronic voting systems, personal response systems, interactive student response systems, and classroom performance systems) includes one hand-held remote per student, receiver (infrared or radio frequency, depending on the system), computer for recording student responses, and means for projecting information to the class (Lowery, 2005). Positive ARS use outcomes are widely reported at the college level (e.g., Draper & Brown, 2004; Judson & Sawada, 2002; Lowery, 2005; Kennedy & Cutts, 2005), but are less studied at the high school level (e.g., Conoley, 2005). ARS are used in variety of ways including imbedding questions into traditional Powerpoint lectures, recording responses to tests and quizzes, increasing student collaboration, and conducting anonymous surveys. Claims made by ARS manufacturers that the technology increases interactivity and student involvement are largely corroborated by the literature. Student views of ARS are generally positive. For example, at the college level, Uhari et al. (2003) reported that More than 80% of the students felt that voting improved their learning, and most of them felt that it enhanced questioning during lectures, although some students disagreed on this latter point. …