Fig. 5

Dino Problem pretest–post-test scores (n = 124) broken down by conceptual categories (V variation, O origin of variation, I inheritance, F fitness, P population change). The charts illustrate the percentage of students who correctly applied each given principle in their explanation of evolution by natural selection. Based on our rubric in Table 3, a score of two indicates an expert answer in a given category (gray bars), while a score of one indicates a novice answer (white bars). Numbers above the bars indicate the overall percentage of student answers that included a given principle (either at the novice or at the expert level). The Wilcoxon matched-pairs signed-rank test, applied independently to student scores in each of the five categories, indicated that the pre-to-post improvement was statistically significant in all categories with α < 0.005