SummaryTo let student teachers evaluate their pre‐ and post‐instructional ideas, we confronted them with their own ideas on the subject of biotechnology before and after a course with that title. We asked them to compare their own statements before and after the course and used this information for evaluation of the course. The hierarchical concept mapping test has been used for the investigation of associations and reasonings of each student teacher upon the stimulus word ‘biotechnology’. Comments of student teachers have been registered via interviews and written statements. The use of this method as part of a teaching strategy for the improvement of the effectiveness of the course and for the illustration of learning in biology teacher education will be discussed.