What determines a modern human being as opposed to what constitutes a hominim. Is it skull shape, heavy limbs as opposed to more graceful arms and legs, or is it their teeth? We are told that modern humans hybridised with Neanderthals on several occasions – firstly at 300,000 years ago. They also hybridised on several occasions down to around 50,000 years ago when Out of Africa kicked in, various scientists claim. None of their genes, it seems, were inherited by modern humans after 50,000 years ago. This puts a question mark, it would seem, on whether the early modern humans hybridised with Neanderthals and Denisovans. Why didn’t later modern humans inherit the hybrid genes. The argument, as noted in an earlier post, seems to revolve around skull shape and other physical traits. There is no genetic evidence for hybridisation taking place -apart from Neanderthal and Denisovan genes been inherited, to a small degree. The latter could of course have been diluted from the gene pool in the period after 50,000 years ago – although mutation by radiation may seem the most obvious explanation.
It seems hybridisation is now being proposed in ancient East Asia – also dated around 300,000 years ago. See https://www.livescience.com/archaeology/human-evolution/300-000-year-old-teeth-from-china-may-be-evidence-that-humans-and-homo-erectus-interbred-according-to-new-study … which pertains to the discovery of 21 teeth in southern China. They are said to be a mixture of Homo erectus and modern human dentition traits. Whatever, it brings us around to Homo erectus – the hominim, or early human that really colonised the world. They seem to turn up in every corner of the globe. This is the real ‘human journey’ one might say. The teeth actually show that Homo erectus cannot be tagged and bound to a single type but they clearly had variations. In fact, some early modern humans, even in the Holocene, display a number of variations – in southern Africa for example. It seems reasonable to think even earlier early humans had the same propensity for variation. Therefore, onme might think so called hybrids are probably evidence of a similar kind of differing physical types. Amongst Neaderthals, and Homo erectus. We are even told at the link that genetic drift or gene flow could be at play. They are unlike Denisovans or Neanderthals and therefore do not fit into the evolutionary model. It is that what determines whether a fossil is a hominim or a hybrid. At the same time we are informed our human ancestors of the Middle Pleistocene period are being discovered and analysed at a rapid pace, paving the way for a better understanding. What is missing from research into our ancestors is catastrophism – and how mutations might occur.