Date of Award
Doctor of Philosophy
Science Education, Mallinson Institute
This dissertation project focused on pre-service elementary teachers' conceptions of the plant processes of photosynthesis and cellular respiration as being connected, occurring at multiple ecological levels, and working within "nested systems." Participants enrolled in a biology course designed for elementary education majors provided their views of the processes through a series of tasks with a peer, a semi-structured interview, and clarified both photosynthesisand plant cellular respiration directly following classroom instruction on the two topics. The instructor of the course was interviewed after a preliminary analysis of the participants' responses. Data were analyzed using the qualitative analysis computer program The Ethnograph v.5, with attention to whether theparticipants viewed the energy reactions as interconnected, within multiple ecological levels of the plant system, and as "nested systems" of the global ecosystem.
Participants did view photosynthesis as an energy process, but were less committed to cellular respiration as an energy process. While most participants described the processes within multiple ecological levels of the plant system, their accuracy of the concepts within the levels varied. Responses suggested a level of understanding that included few of the ecological levels with descriptions focused primarily on the organism level. Instruction included all multiple ecological levels with focus on the biochemical level. Many participants simplified the two processes in a manner that matched the evaluation of their instruction. Few participants held a "nested systems" view of the global ecosystem. Justifications provided for their explanations were authoritarian, and anthropomorphic, with teleological and tautological reasons also expressed. The pre-service teachers did compare plant functions with analogous human functions; potentially suggesting an intuitive conception. In general, the pre-service teachers viewed plants as dependent on humans, and having use within human society.
This project may have implications for the instruction of photosynthesis and cellular respiration. Analogy of plant processes with humans' use of energy, andthe utility of plants for human society may be a motivating factor for instruction. Instruction that focuses on the organism level first, and provides explicit signposts when moving from one ecological level to another may provide clearer understanding of the processes.
Brown, Mary H., "Understanding Photosynthesis and Plant Cellular Respiration as “Nested Systems”: The Characterization of Pre-Service Teachers’ Conceptions" (2005). Dissertations. 1020.