It's easy to say that species are constantly changing and branching into totally new species. But how do we know where species come from? Phylogenies help show us how all types of species are related to each other and why. These relationships are built into what can be called a cladogram, which links species to common ancestors, in turn showing where, when, how and why these ancestors diverged to form new species. Without phylogeny, it would be extremely difficult to place species into specific categories or relate them to each other. Along with phylogenies conflict can occur over which species should be related to each other. This conflict gives rise to many hypotheses and experiments, which can lead to phylogenetic retrofitting, which means adding some kind of data to a phylogeny that was not originally included. In MSY Lee's article "Origins of the Turtle: Insights from Phylogenetic Retrofitting and Molecular Scaffolds", the origin of the turtle (Testudines) is highly controversial and has been the source of experiments to try to demonstrate whether it should be placed under grade parareptiles anapsid, according to Bayesian analyses, or diapsids as sisters of living archosaurs. The use of experiments that include molecular scaffolding, which is an experiment that involves using the backbone scaffold protein to position turtles in a certain taxa, is used to show where turtles should actually be placed. I find it very interesting that scientists continue to go back and forth between new and old phylogenies, constantly rearranging and questioning their placement. Phylogenies are not only important for showing the origin of species, but also for illustrating how DNA sequences evolve. For example, in class, we were supported and involved by this experiment. While Bayesian inference places turtles across a broad range, parsimony places turtles more specifically near pareiasauromorphs. Furthermore, in the molecular scaffold, a turtle-archosaur clade in the diapsid matrices is very evident, but highly unstable for Eunotosaurus. Eunotosaurus, however, remains with the parareptiles in most scaffolds. This states that turtles could very well be considered parareptiles, despite being sister groups to archosaurs. Further evidence should be done on other close relatives of these taxa, including research on synamorphies to help support the evidence. More experiments applied to the study of the different ancestors and possible sisters of turtles, and even Eunotosaurus, may be what is needed to correctly place turtles in the phylogeny and specific taxa to which they belong..