Eventually the reality will be known, and no doubt it'll be very interesting indeed. A unique spirit not shared by the animals, or by any other part of the physical Creation. Adam and Eve, who were probably born in Africa some 130,000 years ago, were the first true humans. From their infancy they possessed souls, and even the Fall did not alter this. The Bible names their three sons, but no daughters.
Uncomfortable speculations abound.
Despite racial and other apparent differences, we humans have virtually everything in common. Let's use viruses as an example of the former. They're so small that it takes a very sophisticated microscope to see them. The soul is even harder to detect. Generally speaking, you either have one or you don't.