Om elevers förståelse av naturvetenskapliga förklaringar och biologiska sammanhang

Sammanfattning: The main purpose of this study is to obtain more detailed examples of how students' understanding of complex biological concepts develop at a time when they are first confronted with a more formal way of explaining science at school. Data were gathered from 16 students at two different periods in their schooling: at the beginning of the seventh grade and the end of the ninth grade. The data obtained from essays and from transcriptions from clinical interviews have served as complementary information in the analysis of students' understanding of evolution by means of natural selection.The analysis shows a considerable variation among the students in grade 7 regarding their general biological knowledge. One student explained the evolution of the species by means of biological concepts as mutations, selection, etc. The majority of the students, however, used teleological arguments in their explanations and seemed to share the same basic idea that evolution served the purpose of adaptation. The corresponding data from grade 9 shows that the majority of students still seemed to base their understanding of evolution on teleological arguments. Only one student had turned from a teleological explanation to a Darwinian explanation. Nevertheless the majority of the students expressed a deeper understanding of evolution in grade 9 than in grade 7, although no complete conceptual change had occurred. The following changes in students' understanding were observed:- increased knowledge about the history of evolution- consciousness of evolution as something very complex and difficult to grasp in its entirety- a change towards a more scientific way of explaining.The students' ways of reasoning have been summarized in a "Students' explanation schemata” showing the pattern of frequently occurring ideas and explanations. One reasonable interpretation of the problems many students seem to have in arriving at a more consistent Darwinian theory of evolution could be that, because of the complexity of this theory, they cannot see it as a new line of reasoning compared with their earlier way of thinking.