This study examines the perceptions and attitudes of 234 Greek secondary school students regarding ecological issues arising from human intervention in food webs. The results of this study indicate that the following factors are crucial for students’ attitudes toward environmental protection: scientific knowledge, perceptions of the relationship between humans and nature and personal motivations. It was found that those students who understand the interconnectedness of populations in food webs are able to evaluate arguments on an ecological issue and have positive attitudes toward environmental protection. However, students who have limited knowledge in evaluating arguments make decisions to solve environmental problems based on their perception of human-nature relationships. Thus, it has been shown that students who adopt an ecocentric or biocentric view sometimes adopt a negative or neutral attitude toward environmental protection because their incomplete knowledge leads them to misjudge the ecological impact of the proposed solutions. This study confirms that the development of values is best accompanied by the development of basic ecological knowledge. It also recognizes the usefulness of food webs as a means of revealing students’ worldviews. Finally, the food web proves to be a specific indicator of the attitudes studied.