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.

A hypothesis-driven laboratory is described that introduces students to the complexities of ecosystem function. Students work with live algae, brine shrimp, and sea anemones to test hypotheses regarding the trophic interactions among species, the exchange of nutrients and gases, and the optimal ratio of producers to consumers and predators in enclosed, artificial-seawater ecosystems. In the initial iteration of the activity, multiple ecosystems that differ in their composition of organisms are assembled according to simple recipes by individual students or small lab groups. Two weeks later, the ecosystems are deconstructed, and the students tally the organisms and assess key water-quality measures, including salinity, pH, and ammonia levels. Some sample data and results are presented, as well as tips for successful implementation.

This article outlines an exercise that assesses student knowledge of food-web and energy-flow concepts. Students work in teams and use manipulatives to build food-web models based on criteria assigned by the instructor. The models are then peer reviewed according to guidelines supplied by the instructor.