Evolution by natural selection is a theory that has unified the biological sciences but divided the general public. In this talk, I shall discuss how early-emerging, essentialist constraints on the conceptualization of biological kinds impedes learning about population-level phenomena like evolution and natural selection. Data from cognitive studies (Shtulman, 2006), developmental studies (Shtulman & Schulz, 2008) and teaching-intervention studies (Shtulman & Calabi, 2011) all suggest that students initially construe evolution as the uniform transformation of all species members ? a view consistent with early views of evolution in the history of science (Mayr, 1982). Only through specialized instruction are students able to replace their "transformational" misconceptions with a correct, "variational" view of evolution, in which evolution is construed as the selective propagation of within-species variation. This transition is marked not only by an increased understanding of what evolution is but also by an increased willingness to accept evolution as true. Less