The purpose of the study was to investigate university learners' visual attention during a PowerPoint (PPT) presentation on the topic of "Dinosaurs" in a real classroom. The presentation, which lasted for about 12-15 min, consisted of 12 slides with various text and graphic formats. An instructor gave the presentation to 21 students whose eye movements were recorded by the eye tracking system. Participants came from various science departments in a national university in Taiwan, of which ten were earth-science majors (ES) and the other 11 were assigned to the non-earth-science group (NES). Eye movement indicators, such as total time spent on the interest zone, fixation count, total fixation duration, percent time spent in zone, etc., were abstracted to indicate their visual attention. One-way ANOVA as well as t-test analysis was applied to find the associations between the eye movement data and the students' background as well as different formats of PPT slides. The results showed that the students attended significantly more to the text zones on the PPT slides and the narrations delivered by the instruction. Nevertheless, the average fixation duration, indicating the average information processing time, was longer on the picture zones. In general, the ES students displayed higher visual attention than the NES students to the text zones, but few differences were found for the picture zones. When the students viewed those slides containing scientific hypotheses, the difference in attention distributions between the text and pictures reduced. Further analyses of fixation densities and saccade paths showed that the ES students were better at information decoding and integration. (Contains 4 figures and 6 tables.)