 Figure 1  provides a typical contemporary example of a phylogenetic tree—a branching diagram that displays genealogical relationships. Phylogenetic trees like these include branches (the lines) and nodes (where the lines branch or come together, depending on the direction you are reading the tree). Terminal branches are marked with the entities whose evolutionary relationships are being studied. In this case those entities are species or higher taxa, but trees may be constructed for other taxonomic levels, or any other biological entities whose evolutionary relationship can be studied (e.g., viruses, stretches of DNA, extinct taxa). Phylogenetic methods can even be employed to study ontogeny or cultural evolution, e.g., they have been used to construct cell fate maps to reveal how the developmental parts of a single organism are related (Salipante &amp; Horwitz 2006), and used to reconstruct the expansion of language families and help estimate historical human migration patterns (Gray &amp; Jordan 2000; Gray &amp; Atkinson 2003; Gray, Drummond, &amp; Greenhill 2009). More recently, phylogenetic tools have been used to aid epidemiology studies of COVID-19 (Lemieux et al. 2021).