This paper gives an example of how to address the challenge of designing a learning progression that describes student thinking, with the necessary specificity to align instructional opportunities and assessment tools. We describe the Conceptual Underpinnings of Evolution project and the iterative process of developing a novel learning progression…

This paper presents an activity that engages students in model-based reasoning, requiring them to predict the behavior of the trp and lac operons under different environmental conditions. Students are presented six scenarios for the "trp" operon and five for the "lac" operon. In most of the scenarios, specific mutations have…