"Human Antiquity" by Feder and Park presents an overview of the fossil evidence for our evolutionary history, current theories of species assignment, and current theories of the driving forces behind the speciation of our family tree, for the most part. They don't go into detail about the rationale behind separating all these fossils into separate species, other than to say that they are different or "quite different." This makes it difficult for me to assess for myself, for example, what exactly distinguishes Homo rudolfensis from Homo habilis. They say that most of these categories are based on skeletal morphology, usually on specific traits observed in skulls. Which, as we learned from Prost's study of skeletal growth and development in his book "Who Were Neanderthals?", does not necessarily reflect genetic makeup and may just be an example of variation within a normal range. This indicates, at least to me, that the task at hand is to determine exactly which features are synapomorphies that we can use to distinguish separation. We need to be sure that the synapomorphies we observe are truly synapomorphies, the result of traits passed down genetically from a common ancestor. If the appearance of an adult skull is an indirect result of brain growth, then we need to reevaluate how we evaluate the morphology of fossils. This is not as easy a task as looking at an object and seeing how it is different, but this should not be a big surprise since the more we look at nature the more we find that it is rarely "easy" to look at. Feder and Park present a list of traits used by paleoanthropologists to distinguish the appearance of skeletal features and characterize these changes over time. The... middle of paper... If we want to know anything about our evolutionary history, we need to start by looking where it matters. If we find that the methods we use and the things we look at don't tell us what we want to know, then we need to reevaluate those methods and try to find others that tell us what we want to know. By observing the growth and development of bones we have learned that the characteristics we observe don't tell us what we thought they did. We need to find a different way to study the traits that impact the course of adaptive tendencies. By studying the growth and organization of the brain we have a new place to look. Positional analysis provides us with a way to actually identify applicable and meaningful traits, such as how bone growth processes reflect brain growth. This allows us to continuously monitor ourselves and avoid making the same mistakes.