Are Humans Hybrids?
Thomas Kuhn author of Structure of Scientific Revolutions, views science as progressing in two discrete ways. The normal phase involves scientists working with a theory that helps them solve problems. The theory is usually supported or refined by their research. In a second revolutionary phase, the theory no longer solves the new problems presented it. There is hot debate between various groups. The old guard hangs on to the traditional theories while others search for a new theory. It appears that palaeoanthropology is on the verge of a revolution.
The traditional evolutionary view of the birth of humanity was assumed to be linear series of missing links. Over the past decade, that view has begun to change as more and more hominid species have been discovered and evidence continues to mount that these species coexisted together and in some cases interbred with modern humans and perhaps with human ancestors.
Humans have been around for about 200,000 years and we now know they shared the planet with a number of other hominids. The Journal Science reported this week that at least eight genes that account for nerve growth and language development came from the Denisovans. Denisovans lived in Asia and were closely related to Neanderthals. All that is known about the Denisovans comes from the finger of a 7-8 year old girl that lived about 41,000 years ago and two teeth found at the Denisova Cave in the Altai Mountains of Southern Siberia in 2008. Analysis of the DNA of the finger bone showed it to be a new type of hominid. About 6% of the DNA of Melanesians, Australian Aborigines and other groups in Southeast Asia is derived from Denisovans. There is an apparent over-representation of immune system Denisovans alleles in humans which suggests a positive selective pressure for their retention in modern Southeastern and African humans(pdf). The mapping of the Denisovan genome also indicated that they had dark skin, brown hair and brown eyes.
Last month, the journal Cell reported that a genetic analysis of modern humans suggested that the Neanderathal-like hominids remained in Africa until 25,000 years ago and interbred with humans.
A study in 2010 found that the average human DNA contains 1% to 4% Neanderthal DNA that boosts modern humans’ immune systems. Homo Neanderalthalus were human-like in appearance with thick brows and chests. They died out about 30,000 years ago. They wore clothes, used fire and decorated themselves with beads or hunting trophies. They probably had a rudimentary language. However, the Neanderthal diet was much more meaty and they hunted by ambushing prey. Neanderthals could not run as far or as fast as modern humans and the Neanderthal culture was more primitive; they produced few if any cave drawings and their tools were more primitive.
Several other forms of hominids are known to have coexisted with humans. Homo erectus sensu stricto lived from 1.8 million to 30,000 years ago in caves in China. A similar form of hominid, Homo Ergaster, lived in Africa until about 60,000 years ago. The multiregional hypothesis argues that humans interbred with this species.
Homo Rhodesiensis died out about 125,000 years ago. It’s classification is still debated. Homo Cepranensis may have lived until 50,000 years ago but little is known as evidence comes from only one skull found in Italy. The Red Dear Cave People died out about 11,500—14,000 years ago. They have not been classified. They may have been primitive humans, a separate hominid class or human Denosoivan hybrids. Finally, the video above describes the mysterious The Flores or Hobbit Man that appears to have died out around 12,000 years ago after living on the island of Flores for a million years. Natives claim they died out in the 1500’s.
Scientists believed that other hominids were mostly off-shoots that were too different from modern humans to have mated with our ancestors. Now, the DNA evidence indicates interbreeding did take place and that some traits remain in modern humans. Perhaps the same interbreeding occurred between pre-human species. Before humans walked the earth we know that at least three hominid walked the plains of Africa together two million years ago. All these findings suggest a complex and crowded pictures for the origins of humanity.
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