Evolution is the underlying framework upon which all biology is based; however, when it comes to learning evolutionary concepts, many students encounter obstacles. There are many reasons as to why these obstacles occur. These reasons deal with evolution being treated as a discrete topic among many within a biology curriculum, misunderstanding the nature of science, and personal difficulties with understanding due to evolution's seemingly abstract nature. In this article, we propose a different way of thinking about and teaching evolution in grades K-12, and it surrounds four core areas essential to the understanding of evolution: variation, selection, inheritance, and deep time. Possibilities for how these areas can affect learning are described and implications for assessment are also discussed.Keywords Evolution education . Evolution teaching approaches . Learning progressions . Understanding evolution . Evolutionary beliefs . Evolution curricular approaches When Charles Darwin proposed his theory of natural selection in the 1800s, this profoundly changed the social and scientific landscape of the time. Few in society of the time could accept this paradigm shift, but the Darwinian shift had hallmarks of the scientific process, where competing explanations of the natural world were, and still, looked at through open-mindedness and a critical lens. A similar conflict occurred in geology over Wegener's theory of continental drift. Once mapping of the ocean floor revealed the mid-oceanic ridges and trenches that Wegener's theory required, the geology community quickly adopted the theory, which now forms the basis for understanding much of geology. Evolution holds a similar place in biology. The integration of genetics with evolution that started in the 1930s (Haldane 1932) provided the "missing link" in biology that mid-oceanic ridges had provided to geology. As a result, evolution is the overarching theory that provides the stable bedrock on which biological research and understanding are based. While new details and discoveries in evolution continue to emerge, evolution is the basis for our understanding of biology. Yet despite this centrality, evolution continues to be poorly understood by students, educators, and the public.

The fundamental scientific concept of evolution occurring by natural selection is home to many deeply held alternative conceptions and considered difficult to teach. Science teachers’ subject matter knowledge (SMK) and the pedagogical content knowledge (PCK) component of knowledge of students’ conceptions (KOSC) can be valuable resources for helping students learn difficult science concepts such as natural selection. However, little research exists that explores the relationship between science teachers’ SMK and their KOSC on evolution by natural selection. This study explores the relationship between SMK and KOSC through the participation of four biology teachers at a single high school and thus deepens our understanding of the teacher knowledge base. Main data sources are teacher interviews in which each teacher answered SMK‐type questions and predicted what their students’ most common alternative conceptions were by using the Conceptual Inventory of Natural Selection (CINS). Other data sources include student responses on the CINS and classroom observations. Findings revealed relative independence between SMK and KOSC, although there is likely a minimum threshold of SMK to recognize student alternative conceptions. However, our work also revealed ways in which teachers were not leveraging their KOSC and suggest potential avenues for future inquiry. © 2016 Wiley Periodicals, Inc. J Res Sci Teach 54: 219–246, 2017

Graphing is a fundamental part of the scientific process. Scales are key but little-studied components of graphs. Adopting a resources-based framework of cognitive structure, we identify the potential intuitive resources that six undergraduates of diverse majors and years at a public US research university activated when constructing scales, and identify classes of resources that share similar characteristics. The students constructed scales for data sets that range over 10 or more orders of magnitude, and were interviewed in depth about their scales. The data were analyzed using the constant comparative method. We identified four classes of resources: (1) ''prior drawing experience'' resources that include show all elements and what you see is what you get; (2) ''wide range'' resources that are used to make sense of a data set with widely varying values, such as zoom in, ratio, and conversion; (3) ''prior graphing experience'' resources that draw from previous work with graphing, including powers-of-ten scales and linear scales; and (4) ''fundamental knowledge'' resources, such as halving. These resources, while identified among undergraduates, may indicate promising educational approaches to graphing in middle and high school. Secondary school science curricula and instruction that acknowledge and build on student resources will likely result in deeper understanding of conventional scales and graphs among students at this age and thus allow for more effective instruction at the undergraduate level. Instructional activities that might activate and build upon the resources identified are presented. #

Background: Previous work found four areas critical to understanding evolution: variation, selection, inheritance, and deep time.

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