Not every experience builds thinking and not always thinking shapes experience; that was something I learned during my rural practice as biology teacher in the town of San Zenón (Magdalena).In this practice the journal was my guide, through words I found myself with new experiences, with people, time and its changes.It was to confront, apprehend, teach and above all recognize the complexity of culture and its meanings.Perhaps the main objective of this paper, beyond showing a life or a biology teaching experience, is to argue why reflective practice and participant observation must occupy the most important place within the self and in the doing of teachers, as well as recognition of the context and participatory action.From a more critical perspective of the teacher's role, the recognition of the changes in the educative reality can only be given from the understanding and the construction of meanings, from the subject, as a complex of progress, setbacks, symbols, emotions, practices and thinking, like a cultural body and not as a black box.