First-Year University Students' Understanding of Photosynthesis, Their Study Strategies & Learning Context

Abstract

O VER the last decade, research on student learning has increasingly focused on the development of students' conceptual knowledge (West & Pines 1985). There have been moves away from views of the student as an empty jug into which knowledge is poured and moves toward recognition of the effects of prior knowledge on students' subsequent learning (Ausubel, Novak & Hanesian 1978; Entwistle & Ramsden 1983). Advice on study skills has moved from focusing on techniques for aiding recall to emphasizing reflection on learning and acknowledging different contexts (Entwistle & Ramsden 1983). In this paper, we focus on students' learning of the concept of photosynthesis-the importance of which is reflected in its being taught at all levels of the education system. In studies on students' views of photosynthesis it has been found that although most students appreciated that light was involved, few grasped the notion of an energy transfer, the role of the chemical energy produced, the role of water or the idea of energy storage (Wandersee 1983; Bell 1984; Bishop, Roth & Anderson 1985; Hegarty-Hazel 1985; Haslam & Treagust 1987; Barker & Carr 1989). There was some confusion about the respective roles of carbon dioxide and oxygen. Many students were unable to link photosynthesis with other physical and chemical processes such as water uptake and respiration. Most of the biochemical reactions of photosynthesis found in curricular science belong to the domain of symbolic knowledge, whereas notions such as plant food are part of a student's intuitive knowledge (West & Pines 1985). Students' notions of plant food may be affected by packets seen on supermarket shelves and may not be compatible with scientists' views of photosynthesis. The discrepancies between the students' and scientists' views as mediated via the curriculum remained remarkably intractable in the face of successive rounds of teaching, though diminished somewhat in the final years of secondary schooling or in the first year at a university. For example, Barker and Carr (1989) found that hardly any 13-year-olds used the concept of energy storage and only about 15% of 17-year-olds and first year university students did so. However, corresponding responses for the concept of carbohydrate production were higher (20% rising to 45% and to 65-70%). Barrass (1984), discussing the written work of students who had passed school examinations in biology, noted common misconceptions: Respiration occurs in animals and photosynthesis occurs in green plants; green plants photosynthesize in sunlight and respire at night. Students did not realize that respiration occurred all the time. Barrass suggested that the use of summary equations may cause some students to think that respiration and photosynthesis are alternatives and cannot occur simultaneously. It appears that the nature of students' conceptual development and their misconceptions is not simply a function of the topics to which they have been exposed by teachers and texts, or of the representation of those topics. Other important elements include students' prior knowledge and approaches to learning. Biggs (1979) suggests that deep/meaningful approaches to study promote meaningful learning. He has shown that surface/rote approaches resulted in less complexity, whereas deep/meaningful approaches resulted in greater complexity. Novak (1977) has explored the demands for meaningful learning in different educational settings and has demonstrated the crucial role of prior knowledge. Entwistle and Ramsden (1983) linked these two aspects of student learning, showing that students' approaches to study are affected by their lack of prior knowledge and by various contextual factors in the Elizabeth Hazel is Associate Professor at the Centre for Learning and Teaching at the University of Technology, Sydney, P.O. Box 123, Broadway 2007 NSW, Australia, and Michael Prosser is a Professor at La Troke University, Bunorora Vic 3083 Australia.