From the Modern Synthesis to the Molecular Synthesis: updating how we teach and assess evolution by natural selection

Evolution by natural selection is recognized as both the most important concept in undergraduate biology and the most difficult to teach. Unfortunately, teaching and assessment of evolution have been impaired by legacy approaches that focus on Darwin’s original insights and the Modern Synthesis’ integration of Mendelian genetics, but ignore or downplay advances from what we term the Molecular Synthesis. To create better alignment between instructional approaches and contemporary research in the biosciences, we propose that the primary learning goal in teaching evolution should be for students to connect genotypes, phenotypes, and fitness. To support this approach, we developed and tested assessment questions and scoring rubrics called the Extended Assessing Conceptual Reasoning of Natural Selection (E-ACORNS) instrument. Initial E-ACORNS data suggest that after traditional instruction, few students recognize the molecular synthesis—prompting us to propose that introductory course sequences be re-organized with the molecular synthesis as their central theme.