RESUMO
The main aim of this study is to teach students to take a systems perspective in understanding complex biological problems. Two lessons were designed and tested in two secondary classes (15- to 16-year-old students), using a lesson study approach. Three students from each class were observed more closely when visualizing and reasoning about two complex biological problems. The results, based on student worksheets, peer discussions, classroom observations, and interviews, indicated that students were able to visualize complex problems with the aid of a systems model based on eight system characteristics: boundary, components, interactions, input and output, feedback, hierarchy, dynamics, and emergence. Moreover, explicit scaffolds encouraged students to reason across different levels of biological organization. Based on the findings, four design guidelines were formulated: 1) Start with a central complex problem/question. 2) Let students visualize a complex biological problem using a systems model. 3) Assist students in reasoning step by step within and between the levels of biological organization. 4) Make students explicitly aware of the use of the system characteristics in various contexts. As systems thinking assists students in creating an overview of a system and reasoning about a complex problem systematically, it is also valuable outside the biology classroom.
