Reasoning about evolutionary history: Post-secondary students' knowledge of most recent common ancestry and homoplasy

Evolution curricula are replete with information about Darwin's theory of evolution as well as microevolutionary mechanisms underlying this process of change. However, other fundamental facets of evolutionary theory, particularly those related to macroevolution are often missing. One crucial idea typically overlooked is that of most recent common ancestry and its relevance for investigating evolutionary relationships among taxa. Deep understanding of most recent common ancestry is particularly important for comprehending the reciprocal concept of homoplasy (convergent evolution). This study examines knowledge of these two concepts among 127 post-secondary students as a function of their biology background. Analyses of responses to two questions indicate that students fail to acquire and/or retain knowledge of the significance of most recent common ancestry and of homoplasy, despite potential for prior exposure to them throughout K-12 and post-secondary education. These results indicate a need for improvement in evolution education to ensure that students acquire an appropriate understanding of evolutionary relationships and processes as a whole.