The uncertainty of the science of human origins is reflected in the case of Homo heidelbergensis. Some researchers are not even sure it is a valid species, and others are unsure if the African specimens are for the same species as the European specimens. And its role in the lineage of Homo sapiens results in a variety of views. It could well be that some of the specimens found can be categorized as Homo erectus or perhaps Neanderthal. Some descriptions are made on the basis of just a cranium or even just a mandible.
Ultimately, according to Unification Thought, earlier species provided the foundation for later species and ultimately the origin of human beings. Even then, from a religious perspective, at some point human beings would have been endowed with a spirit or soul.