Previous research about the presence of nature of science (NOS) within science textbooks has been found to be lacking in sufficient coverage. However, given the shift in how scholars conceive of NOS, the shortcomings may not be present in the textbooks but rather in the NOS frameworks used to analyze textbooks. Whereas traditional NOS has taken a more generalized approach to describing scientific practices, the family resemblance approach (FRA) to NOS recognizes variability in the scientific disciplines as reported by practicing scientists as well as philosophers and historians of science. Instead of suggesting that NOS can be applied equally in educational settings to all scientific disciplines, the FRA accounts for cognitive-epistemic and social-instructional conceptual elements which more authentically represent science. This study sought to evaluate textbooks using this more recent NOS conceptualization to explore the potential range of NOS aspects. Using the proposed FRA categories, seven German biology textbooks were analyzed with qualitative content analysis. The combination of cognitive-epistemic and social-institutional systems of science revealed that the FRA was a suitable mechanism for analyzing textbooks' coverage of NOS. Notably, FRA's distinct attention to modeling (absent from the discipline-general NOS approach) revealed its presence in textbooks that would have gone unnoticed. Another finding was that the textbooks tended to emphasize the cognitive-epistemic systems over the social-institutional. Finally, this study found that even with a broader set of categories and subcategories to the FRA, the application to analyze was reliable.