Explanation of natural phenomena at one level of biological organisation almost always involves causes that are found at other levels. Although scientists thinking across levels find it easy to explain physiological phenomena, students often perceive this as a challenge. We developed a new graphic organiser called Zoom Map, which is a mode for structuring biological information along the levels of biological organisation and is designed to guide biology students when they need to consider the levels of organisation. The aim of this study is to examine how Zoom Map helps students explain a common phenomenon in plant physiology: leaves that are upright or wilted. Accordingly, we designed a teaching experiment covering 13 students. During the experiments, the students were videotaped. We used qualitative content analysis to examine the explanations. Our findings indicate that Zoom Map improved students' explanations of the phenomenon across multiple levels of organisation: The students used more levels than before, and they referred to lower levels that were lacking previously. Therefore, it can be concluded that students who use Zoom Map are supported in their ability to explain a biological phenomenon across the levels of biological organisation.