A recent report describes a very well preserved skull that was discovered in China in the 1930’s during the Japanese occupation and hidden away until the last couple of years and then handed over to paleontologists. It is believed to be the skull of one of the species of human relatives of modern man. It is a “hominin” species that is being described as Homo longi, or Dragon Man.
The skull is very reminiscent of the Neanderthal Man skull although it seems even closer to modern man in ways. It has the prominent eye ridges, larger teeth and large brain cavity that characterizes Neanderthals. But the face is flatter, the jaw more human-like.
What is in dispute is whether this represents a complete skull of the Denisovan Man. The Denisovans were another early human species whose remains and DNA have been found in Siberia and Tibet. The fossil evidence available is currently very limited. It consists of a few finger bones and a small amount of jaw and teeth. But interestingly, there is enough DNA material available to show that Denisovans have left some of their DNA in us and in fact cross-bred with both humans and Neanderthals.
The speculation is that the first homo sapiens or its close ancestor reached the north and split into two populations the Neanderthals ended up in Europe and the Near East. The Denisovans went East and inhabited Asia. And this is a simplification because there are several other species of hominins that were still extant in Eurasia. Homo erectus, H. luzonensis, H. heidelbergensis and H. naledi existed in that same period of time (from a million years ago to fairly recently).
Later waves of Homo sapiens would then meet up with this first wave and then coexist, compete, mix with and ultimately displace these near relatives. What is clear from this story line is that humans have constantly evolved to adapt to their changing environment as they migrated from Africa to Eurasia. What is less comfortable for people today to discuss is the amount of genetic diversity that exists in the family of man. In any other animal group, we would describe the existing races of man as species, or at least subspecies, that intergrade into each other at the edges of their geographical ranges. And of course, the reality of the cosmopolitan nature of modern human civilization means that all these subspecies are rapidly mixing to form new variations. And what the DNA evidence has shown us is that the migratory tendencies of human groups have repeatedly stirred the pot of human genetic groupings. When the people that would become the ancestors of the Indo-Europeans began their treks westward and eastward, they spread their language and their genetic material from India to Britain. Similar migrations have occurred right into nineteenth century with the colonization by the Europeans around the world. And the present mania over diversity has further mixed things up.
But regardless of the semantic description of human genetics, it is fascinating to see just how dynamic our lineage is. Apparently, the changes in terrain, climate and food resources have quickly selected for changes in the human form and physiology. Some people have claimed that human technology has now eliminated the possibility of human physical evolution. But that is simply not true. In the last ten thousand years the human brain has evolved based on selection for complex thinking needed in more complex human societies. This leads to further refinements and selects for individuals that can survive and thrive in the complex and changing environment that is our human world. What this tells us is that we become what we need to be in order to adapt to our environment. What this tells me is that we need to choose wisely how we organize our society. It would be a shame to see our remarkable species end up as an ant colony.