The aim of the study is to examine the curricula that are important for biology teaching. The study was carried out within the scope of qualitative research, and the content analysis of the curricula was applied. The biology units, number of concepts, and learning outcomes in the different curriculums were examined. Revised Bloom’s taxonomy was used to analyze the learning outcomes. During the coding process, consensus and agreement indices between coders were calculated. The results of the analysis showed that biology acquisitions accumulated in understanding factual and conceptual knowledge at all educational levels, that the acquisitions for higher-order thinking skills were not evenly distributed at class or unit levels. Consistent with these, it was observed that the concept density was high at all education levels. While the middle school (5-8) and secondary education (9-12) programs support each other in terms of spirality in the division of the biology subject area in the curriculum units, it has been understood that the content of the subject area can to be developed at the primary school (3-4) level.