Academic literacy has become a commonplace for institutions of higher education in Latin America. First efforts in this direction are the investigations that have been developed with increasing strength and amount so far this century. In this context, the general objective that guides this study is to determine the literacy levels of academic writing identified from the communicative purposes present in the writings of a group of freshmen of the subject Morphophysiology: Animal Function, as part of an undergraduate program in Biology at a university belonging to the Honorable Council of Rectors of Chile. Specifically, these writings respond to a writing task based on the genre "research paper" in order to account for a problem and solve it, following the steps of a research in the subject area. The methodology used to conduct this research is qualitative, applying the technique of content analysis. The results allow us to determine that the predominating level of literacy in academic writing, even though its percentage is not significant, is the one we have called "explanatory", which is followed by the "reproductive", "relational", "proactive" and finally "justifier" levels. These levels correspond to different communicative purposes that emerged from the analyzed text segments, which shows that students are at an initial level of academic literacy both in terms of scientific domain and writing ability, but in regard to the explanation there is a potential that may be developed in the following stages of disciplinary training.