Connecting photosynthesis and cellular respiration: Preservice teachers' conceptions

The biological processes of photosynthesis and plant cellular respiration include multiple biochemical steps, occur simultaneously within plant cells, and share common molecular components. Yet, learners often compartmentalize functions and specialization of cell organelles relevant to these two processes, without considering the interconnections as well as the significance of the plant as an independent biological system functioning as a nested component within local and global ecosystems. Understanding connections among biological systems at macro and micro levels is important to biological literacy. This study examined preservice elementary teachers' conceptions of photosynthesis and plant cellular respiration, with attention to interconnections and systems. Participants were limited in their understanding of the processes impacting multiple ecological levels, and they held inadequate representations of interconnections between the processes. Participants' views were laden with sociological and egocentric components. They often compared plant functions with analogous human functions. Most participants viewed plants as dependent on humans while having societal use. Justifications for views included nominal knowledge of the processes; experiential authoritarian reasoning; and anthropomorphism. We discuss instructional implications in light of the findings. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 791–812, 2009     

Academic Functioning and Peer Influences: A Short‐Term Longitudinal Study of Network–Behavior Dynamics in Middle Adolescence

In this study, the associations between peer effects and academic functioning in middle adolescence (N = 342; 14–15 years old; 48% male) were investigated longitudinally. Similarity in achievement (grade point averages) and unexplained absences (truancy) was explained by both peer selection and peer influence, net of acceptance, and connectedness. Friendships were formed and maintained when adolescents had low levels of achievement or high levels of truancy. Friends influenced one another to increase rather than decrease in achievement and truancy. Moreover, friends’ popularity moderated peer influences in truancy in reciprocal friendships but not in unilateral friendships, whereas friends’ acceptance moderated peer influences in achievement in both unilateral and reciprocal friendships. The findings illustrate the dynamic interplay between peer effects and academic functioning.     

The effects of explicit timing on middle‐school students’ writing production across 5‐ and 15‐min sessions

Enhancing rates of accurate, active, academic responding can enhance learning. Both temporal manipulations (i.e., reducing time to work on assignments) and providing multiple distributed temporal cues (MDTC), sometimes referred to as explicit timing, have been shown to enhance rates of accurate mathematics responding. The current study was designed to evaluate the effects of session length (i.e., 5 vs. 15 min to write) and temporal cues (i.e., a single initial temporal cue vs. MDTC) on seventh‐ and eighth‐grade students writing assignment rates and writing accuracy. Results showed that the 5 min writing sessions did result in significantly greater rates of accurate responding than the 15 min sessions; however, explicit timing did not significantly alter writing rates or accuracy. These findings suggest that educators can enhance rates of accurate writing by reducing writing session lengths. Discussion focuses on applied implications of providing briefer writing sessions and future research investigating the interaction between multiple temporal cues and assignments.