In genetics education, epigenetics is an important emerging concept. When communicating biology, external representations help students understand epigenetic phenomena since these representations depict essential visual features and symbolism. This study explores how students interact and reason with different visualizations that communicate epigenetic phenomena presented at different levels of biological organization and modes of representation. The aim of the study is to investigate how different modes of visual representations depicted at different organizational levels mediate students' meaning making of epigenetic concepts. To identify students’ interpretation of the visualizations, the CRM model was used as an analytical tool. In an exploratory approach, thirteen students interpreted and discussed six visualizations representing different levels of biological organization at various degrees of abstraction for about 20 minutes as part of semi-structured focus group interviews. The results show that influence of the representation mode and depicted biological organization level is important in students’ meaning-making of epigenetic visualizations. Previous research has shown that students’ interpretation ability of abstract science concepts is supported by the use of different representations. This study concludes that supporting this ability in an epigenetics education context is dependent on the use of different representation modes communicated at various levels of biological organization.

Keywords: Visual learning, CRM model, levels of biological organization

Modern genetics is difficult for students to understand. The nature of biological entities are embedded in multiple hierarchical (macro, micro and sub micro) levels of organization (Marbach-Ad & Stavy, 2000). To make meaning of and understand biological phenomena requires interpretation of all these levels (Tsui & Treagust, 2013, Knippels & Waarlo, 2018). The macroscopic (organismal) level can be defined as visible objects, i.e. biological characteristics that are visible to the naked eye, the microscopic (cellular) level as objects visible under a light microscope, and the sub microscopic (biochemical) level as molecular objects that cannot be observed directly such as DNA and proteins (Marbach-Ad & Stavy, 2000). Learning with visualizations can improve students’ conceptual understanding of biological phenomenon by promoting representational competence. In particular, the ability of students to decode and interpret visualizations represented at the sub micro level is heavily influenced by the diversity of visual information and symbolism inherent in different visual representations (e.g., Ainsworth, 2006).

Epigenetics explains how environmental factors at the macro level can influence gene activity at the micro and sub micro levels. It follows that students need to reason between and across different organizational levels to understand epigenetics. This makes for a compelling didactic case in investigating students’ meaning making when interpreting multiple visual representations. This study explores how different modes of representation communicated by visualizations across and between organizational levels mediate students' meaning making and reasoning about epigenetic concepts. Various factors influence students’ interpretation of scientific visual representations. For instance, Schönborn and Anderson (2009) have shown that factors include the external visual features and graphical markings making up a representation (Mode (M) factor), the reasoning skills necessary to make meaning of a representation (Reasoning (R) factor), and the learner’s prior knowledge of the concepts that the learner “brings” to the representation (Conceptual (C) factor). A student’s ability to successfully interpret and learn from a visual representation through engagement of all three factors (i.e. C-R-M). This study uses the CRM model as an analytical tool to guide identification of students’ interpretation and reasoning with epigenetic visualizations at different levels of biological organization.

The posed research question were: How does the mode and reasoning with the concept of epigenetic visualizations influence students’ interpretation of epigenetic phenomena presented on different levels of organization? How does the mode and level of biological organization influence students’ meaning making of epigenetic concepts?

The visual representations used in the study were depicted at different levels of biological organization (macro, micro and sub micro) and in different modes of abstraction (realistic, semi pictorial and abstract) (e.g., Schönborn & Anderson, 2009). Video observations were adopted to explore students’ interpretation and meaning making of the epigenetic visualizations in focus group activities while they discussed the visualizations in a Swedish school context. Five groups with two to four participants in each group (a total of thirteen students) in grade 9 (aged 15-16 years old) interpreted the six visualizations. The students were first introduced to epigenetics with a video clip that conveyed chemical switches that interact with DNA to regulate gene function. The video clip communicated that the environment interacts with genes inducing changes in appearance that accumulate over time, and that these differences can develop differently between identical twins, for example. Following viewing the clip, students were briefly introduced to the six visualizations. In an exploratory approach, the students interpreted and discussed the visualizations for approximately 20 minutes.With the students structured in focus groups, the first author conducted semi-structured interviews. Interview questions were focused on probing represented epigenetic concepts and the students were encouraged to point at, and explicitly indicate the visual features that they referred to. Moreover, follow-up questions were formulated to further understand how the students interpret and make meaning of the epigenetic visualizations. The analytical process was qualitative and thematic (e.g. Braun & Clark, 2006) with the aim to discern how factors of the CRM model influenced student reasoning and meaning making with the visual representations (Schönborn & Anderson, 2009).

Analysis of students’ interpretation of organizational level revealed that without engaging direct reasoning with the mode (M), i.e. when students reason without referring to any visual representation, they tend to reason about epigenetic concepts (R-C) at the macro level. However, analysis of discussions, students often engaged with visualizations when they represented the sub micro level. Reasoning related to the micro level was not frequently yielded in either of these scenarios. We therefore suggest that visualizations presented at the sub micro level are important for inducing and scaffolding students’ reasoning and interpretation of communicated conceptual knowledge of epigenetics. When representing mode and organizational level simultaneously, we know that semi pictorial and symbolic modes often dominate visual representations at the sub-micro level. This is because of how molecular mechanical processes such as epigenetics are usually visually communicated. Therefore, it is expected that students’ conceptual discussions in genetics would be induced by visualizations because molecular explanations often serve as the basis for conceptual understanding in genetics (Marbach-Ad & Stavy, 2000). Nevertheless, including macro level visualizations in teaching and learning is also of high importance in students’ reasoning. Our study shows that when students turn away from interpreting visualizations in attempting to make meaning of epigenetics concepts, they tend to do so while discussing phenomena at the macro level. Consequently, it seems as if the macro level, and the accompanying realistic representation mode, are important dimensions for students meaning making of epigenetics conceptual content. In this way our study supports Ainsworth’s (2006) and Tsui and Treagust’s (2013) assertions that students’ interpretation of abstract phenomena is supported by using multiple representations. Our study contributes the novel finding to biology didactics that this ability might also be scaffolded in an epigenetic education context when including visual representations communicated in several modes and levels of biological organization.

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