This thesis explores lower secondary students’ meaning-making of epigenetic visual representations within and between biological organization levels. Data obtained from five focus group discussions where students indicated and reasoned about eight epigenetic visual representations were explored. By analyzing students’ interactions with multiple visual representations, and the impact of linking and reasoning patterns on their meaning-making, the research contributes insights to the learning of epigenetics.  Epigenetics, which is gaining rapid importance in emerging biology curricula, is communicated at different biological organization levels, and serves as the meaning-making context explored in the thesis. A compelling biology didactics context, where students are required to reason with multiple representations depicted within and between organizational levels to make meaning about epigenetics. The thesis uncovers three primary findings. First, four linking patterns in students’ meaning-making across and between organizational levels using various visual representations are illuminated. Second, five visual characteristics that influence students’ linking within and between levels were discerned. Third, students’ meaning-making processes were observed to emerge through four phases, which involved form and function attributes of the visual representations, and the transfer of scientific ideas across representations. / <p>Article 1 published in thesis as manuscript, now published.</p>