Food Webs: Implications for Instruction

Abstract

The interdependency of relationships and energy flow in ecosystems are crucial biological concepts that students frequently find hard to understand. They are one of the foundations to the survival of living things and the complex processes that balance life on Earth. The ability to interpret food chains and food webs is fundamental in the communication and understanding of relationships between organisms in the domain of biology. I examine the ways elementary-level students read a simple food web diagram and the effect this has on their understanding of the encapsulated biology concepts. Diagram reading approaches are described along with analysis of how meaning making is influenced by students' preconceived ideas. The results indicate the students experienced a range of difficulties in reading the food web diagram. I conclude that food web instruction must address prior knowledge, challenge preconceptions, and involve deep diagram processing. The research provides insights into the difficulties high school students have in comprehending food webs and understanding relationships in ecosystems.

Interpreting students’ ideas on the availability of energy and matter in food webs

“…Although at the core of the representations of ecosystems presented by the students in our study, it should be acknowledged that interpreting food webs is a challenging task for students (Demetriou, Korfiatis, and Constantinou 2009;Jordan et al 2014;Leach et al 1996b;Preston 2018). Such obstacles can result in the use of everyday knowledge expressed as 'who eats who', which is found in our study.…”

“…Arrows without explanation or even a lack of arrows indicated a vague relationship between the sun and the different organisms. The fact that the students' written explanations were often more precise than their drawings indicates that deciphering and using the signs associated with the visual representations used in textbooks and teaching are far from intelligible for the students in this and previously reported studies (Demetriou, Korfiatis, and Constantinou 2009;Jordan et al 2014;Preston 2018). This problem adds to the impediment of using the vague concepts derived from everyday knowledge that prevents the description of processes with the precision needed to connect them on a more abstract level.…”

“…Visualisations have a central role in both scientific communication (Lemke 1998) and science teaching (Lemke 2002;Preston 2018;Wernecke et al 2018a); they serve as ways for teachers or textbook authors to explain a concept or phenomenon and to gather information on students' views. In our specific case on ecology, students are faced with the challenge of interpreting meanings conferred through written texts, speech, images, etc., and to combine the information into a complex whole.…”

“…In our specific case on ecology, students are faced with the challenge of interpreting meanings conferred through written texts, speech, images, etc., and to combine the information into a complex whole. Even within small student groups, many different interpretations of diagrams, such as illustrations of food webs, may be present (Preston 2018). For example, students interpret the arrows in the food webs in different ways, they read the diagrams in different directions and they often focus on eating ('what eats what'), but not on the transfer of energy and matter.…”

“…For example, students interpret the arrows in the food webs in different ways, they read the diagrams in different directions and they often focus on eating ('what eats what'), but not on the transfer of energy and matter. Preston (2018), therefore, suggested that students should be subjected to repeated experiences of representations, such as food webs, in order to develop their interpretative skills.…”