摘要:The rise of the integration of digital practices in education, particularly in the pedagogical engineering processes of E-Learning Systems (LS), influences the quality of communication, productions and knowledge constructed by learners in teaching contexts at a distance. We consider that the analysis of Learning Needs constituting the model (ADDIE) should take into account the epistemological obstacles generated by the representations of the learners in terms of the choice of effective learning situation. This pedagogical strategy would allow the construction of epistemic knowledge after a phase of diagnosis followed by remediation of the difficulties due to the representations developed by the learners. The case study developed in this paper is a comparison of the evolution of representations related to the concept of "Photoperiodism in livestock" in two groups of students in the agro-food master and belonging to the same class. By comparing the answers of the two groups of learners to the same questionnaire, we have succeeded in highlighting the importance of iterative design in the evolution of the representations of the learners and even the overcoming of the epistemological obstacles generated by it, this.