Evolution is often challenging for high school students to understand because it encompasses an array of interlinked processes that occur across a broad swath of biological scales. To help address this, we have developed a set of freely accessible, online, and interactive lessons that focus on the evolution of sweet garden peas from their starchy tasting ancestors. Gregor Mendel first explored the genetics of garden peas in the mid-1800s; our materials help students explore the basis of the R and r alleles from genetic, protein, cell function, artificial selection, and population genetics perspectives. These Next Generation Science Standards (NGSS)–linked lessons integrate concepts across scales and are designed to be used in a flexible order, with support provided to teachers on how to choose a sequence that meets their students’ needs. Throughout, students act as scientists as they uncover how multiple processes at disparate scales all worked together in the evolution of sweet and wrinkled peas from ancestors that were starchy and round.