Abstract

The discourse of science presents a high degree of complexity for learners, because of its abstraction and combination of differ- ent semiotic resources for representation of scientific knowledge (Lemke, 1998; Halliday & Martin, 1993). Teachers play a central role in approaching their students to learn the valued forms of reasoning, representing and communicating in science. This research was carried out from a social semiotic and system- ic functional linguistics, through a multimod- al discourse analysis of the semiotic options used in teaching biology. The corpus consists of video recordings of the classes of three teachers of biology, teaching the same cur- riculum unit in 1st year of secondary school. Among the findings highlight the semiotic potential of the combination of face to face interaction and whiteboard media, for the co-deployment of schematic drawings along with the spoken and written language with which teachers construct both definitions and explanations of multimodal character.