Providing model‐based accounts (explanations and predictions) of water and substances in water moving through environmental systems is an important practice for environmental science literacy and necessary for citizens confronting global and local water quantity and quality issues. In this article we present a learning progression for water in environmental systems for students in elementary through high school grades. We investigated student accounts of water and substances in water moving through atmospheric, surface, and soil/groundwater systems, including human‐engineered components of these systems. Using an iterative process of model design, assessment, and interpretation, we identified four levels of achievement in student reasoning. Levels 1 and 2 force‐dynamic accounts explain movement of water as interactions between natural tendencies of water and countervailing powers. Level 3 incomplete school science accounts put events in order and trace water and substance along multiple pathways that include hidden and invisible components. Only Level 4 qualitative model‐based accounts include driving forces and constraining factors to explain or predict where water and substances in water move in given situations. The majority of high school students on average provide accounts between levels 2 and 3. We discuss the significance of these results for citizen participation in addressing common water issues. We end with suggestions for how the water learning progression can be used to inform changes to curricula, assessment, and instruction to support students in achieving level 4 performance. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 843–868, 2012

This proof of concept study investigated a secondary science teacher preparation intervention in six university programs across Arizona, California, and Texas. Researchers and science method instructors (SMIs) collaboratively restructured respective science method courses to hold fidelity to an interrelated set of instructional practices that attend to science learning as envisioned in a Framework for K–12 Science Education, while also creating contextualized spaces for language and literacy development targeted to English learners (ELs), but also supportive of “mainstream” students. We observed the teaching of SMIs and preservice teachers (PSTs) with observation rubrics to gauge the fidelity to which they implemented practices. Across programs, SMIs provided opportunities for PSTs to experience the instructional practices as intended, although there was less opportunity for pedagogical development around them. The strongest evidence of PST fidelity to the intervention was found for two practices: “Increasing student interaction” and “Facilitating student talk.” Considerable variation was found across the programs for other practices including some evidence of negative effects. We discuss results in terms of promises for preparing novice secondary science teachers, as well as future directions to overcome challenges that researchers, SMIs, and novice teachers are likely to face when preparing novice science teachers.

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Research on learning progressions has led to advances in understanding student learning about big ideas in science, but teachers struggle to leverage the full potential of learning progressions for classroom instruction. Because learning progressions lay out how students' ideas change over a long period of time, learning progressions could help teachers build better understanding of student thinking, appropriate learning goals, and instructional moves for supporting students in developing more sophisticated ideas. In this study, we explored the potential of learning progression-based curriculum materials to support teachers in developing more sophisticated content knowledge (CK) and pedagocial content knowledge (PCK) for teaching about water in environmental systems. Teachers participated in professional development that introduced them to a learning progression for water in environmental systems and curriculum materials based on this learning progression. Teachers completed written assessments of their CK and PCK prior to the workshops and a year later. Analyses showed that teachers who taught lessons using the learning progression-based curriculum materials showed modest increases in CK, knowledge of learning goals, and knowledge of student thinking. These increases were greater than analogous changes evident for teachers who did not use the curriculum materials. However, even among those who implemented the curriculum materials, teachers' post-assessment performance did not yet reflect knowledge for supporting students in developing modelbased reasoning about water. These results show that learning progressions have potential for supporting teacher learning, but that the ubiquity of traditional school science discourse may limit their potential for both student and teacher progress toward model-based reasoning.

Arctic Char Salvelinus alpinus have colonized northern postglacial lakes within the last few thousand years. Divergent populations have adapted to thrive in the prevailing oligotrophic environments and thus have developed morphotypes with different ecological behaviors. The morphotypes usually differ in size, morphology, coloration, feeding ecology, and/or habitat occupancy. Although morphotypes that have very divergent spawning seasons should become genetically segregated, genetic differentiation, in most cases, has been weak. Thus, results to date have suggested that Arctic Char morphotype separation has been driven largely by the environmentally mediated phenotypic plasticity of the species, with differentiation between morphotypes having commenced too recently to generate substantial genetic drift. Here we used the major histocompatibility (MH) class II genes in an attempt to isolate sympatric Arctic Char morphotypes known to be ecologically differentiated. These morphotypes are from postglacial lakes in *Corresponding both Siberia and eastern Canada, and differ in either diet, habitat occupancy, or both. The MH Class II allelic polymorphism was significantly different between morphotypes. This suggested there is differential heritable adaptation to the natural selection exerted by pathogens unique to each ecological niche within each lake.