While expository texts are an efficient and dominant genre used by science teachers in the United States, they generally lack justification for their claims and fail to reflect science as practice. In contrast, epistemically considerate texts detail specific scientific experiments, providing the reader insight into the methods and data of a biological discovery. This multi-case exploratory comparison analysed videos of students in introductory and advanced high school biology classes who individually read and then discussed the main ideas, sources of justification, and questions raised expository and alternate biology texts. Videos of eight class periods were analysed with a focus on the types of statements students made during the discussion, points of comprehension, questions posed, and whether and how students identified sources of justification for the texts' claims. The epistemically considerate texts were perceived as more difficult to comprehend, but for both developmental levels, and particularly for students in the advanced class, these alternate texts elicited more sequences of productive talk and more elaborative, cognitively deep questions, particularly related to the practices of science. We discuss the potential implications for developing complementary sets of texts to optimise students' science learning and link elements of genre to students' reading and discussion experiences.