Background/Question/Methods   Humans make decisions daily that impact biodiversity and it is essential that citizens understand the implications of these decisions. Yet ecological systems are extremely complex with many details and patterns still being discovered. We developed a conceptual framework that simplifies and structures this complexity and identifies the primary concepts all high school graduates should understand about biodiversity in order to be considered environmentally literate. Based on this framework, we developed and administered written assessments and clinical interviews to over 400 students and teachers at NSF Long-Term Ecological Research sites in Michigan, Maryland, California, and Colorado. Ultimately, these assessments, in combination with teaching experiments, will lead towards a biodiversity learning progression that documents the steps students take along the pathway to literacy about biodiversity. A learning progression is a description of the successively more sophisticated ways of thinking about a topic that can follow one another as students learn about and investigate a topic over a broad span of time (6-8 yrs).

Results/Conclusions   Student data revealed interesting qualitative trends related to genetics and heredity, and community assembly and interactions. Genetics and hereditary continuity is central to what we want students to know about how individuals function and populations change but we have found students' understanding to be weak. We found that many students (1) recognize organisms have hereditary material that determines some of its traits but do not understand how genes interact with the environment to produce a phenotype, (2) believe organisms cannot acclimate to environmental change because of rigid genetic constraints, or (3) think organisms can purposefully change their hereditary material, leading to adaptation. Student understanding of community interactions was often hampered by a lack of familiarity with individual organisms that made up their local community or traditionally defined biomes (e.g. savanna). Also, many students (1) oversimplify the idea of connectedness in nature because they don't recognize functional redundancy, (2) understand the fundamental niche concept but not realized niche, or (3) see competition mainly as direct conflict between organisms rather than mediated through resources. Overall, students appear to make substantial progress in understanding certain facets of biodiversity, such as genetic variation, as they move into the later years of high school, but less progress on other principles in our framework. Finally, patterns in student reasoning about biodiversity appear to be consistent across research sites and that students are not generally familiar with their local ecosystems.