Using course materials to promote visual literacy skills is an important aspect of undergraduate science education. A comparison study was undertaken to determine the composition of visual representations, specifically representations of data generated from experimental research, found in general biology and discipline-specific textbooks compared with primary journal articles. Results showed that there is a mismatch between the types of scientific visualizations in textbooks compared with how science is documented in primary literature, with significant differences in the distribution and complexity of different types of visual representations measured. Also, discipline-specific textbooks contained more opportunities for analysis of experimental data compared with introductory biology textbooks. Thus it becomes important for educators to integrate opportunities for the development of visual literacy skills in undergraduate courses by supplementing textbooks with visual representations of experimental data from other sources such as primary literature. (Contains 1 table and 4 figures.)