Wednesday, August 15, 2018

Specificity of homo sapiens. Part 1 - Evolution evidence

We, Homo Sapiens. How are we different?

Why and how it is Homo Sapiens different from his ancestors and "cousins" Homo Erectus and Homo Neanderthalensis? What is specific to Sapiens?

If we can understand ourselves better, maybe we can evolve better and use our full potential. We have some very useful information about how these various types of humans were able to develop a culture and later a civilization:
  • Homo Erectus - appeared 2 million years ago, and went extinct some tens of thousands of years ago. He was "strong and skillful" (see Biblio 1), but does not improve too much in this period, that is pretty long also at a cosmic scale. 
  •  Neandertals and Denisovans  - also live a long period, between 450K years and 28 K years ago. They were more advanced than H.E., but their evolution has also some obvious limits. Their population does not exceed some hundreds of thousands of individuals and they live in small isolated groups.
  • Homo Sapiens - has a curious evolution. It was able to slowly make a world wide-expansions in all kind of environments (and ... make extinct other human species). In the same time, from 200K years to 15K years ago, H.S. does not make significant cultural changes. And then, "suddenly" .. boom! .. from around 11K years ago start an accelerated development and building a civilization. This big step forward was also the first one produced without being the result of a genetic change.           
"No improvement" Homo Erectus 

To avoid misunderstanding: yes, the culture of H.E. has evolved but was too slow. You can find interesting information about H.E. development in this article: "Laziness May Have Driven Homo Erectus to Extinction" (presenting a scientific study ). 

We will comment here some parts of this article (See [Biblio 1] for article and study).

 << A little way away from the Homo erectus camps was a rocky outcrop that had higher-quality rock but required a trek up a hill. "But rather than walk up the hill, they would just use whatever bits had rolled down and were lying at the bottom," Shipton said." [...] By contrast Neanderthals and early Homo sapiens climbed mountains for high-quality stones and transported them over long distances, according to the statement. >>

<< These early humans were strong and skillful, and they thrived in the region for some time. But once the riverbeds dried out, as sediment samples from the area reveal happened, these people's lack of initiative doomed them.
"Not only were they lazy, but they were also very conservative," Shipton said. Their tools stayed the same in both size and composition as the environment around them changed.
"There was no progression at all, and their tools are never very far from these now-dry river beds," >>

Homo Erectus was smart enough to build tools as no other species before but was too "lazy" to find "better ways" on doing that. Considering that Neandertals and Sapiens had superiors cognitive abilities, we can speculate that this "laziness" is, in fact, related to this aspect. 

Homo Sapiens "niche"

Another recent paper (see [Biblio 2]) written by scientists from the Max Planck Institute for the Science of Human History and the University of Michigan propose a hypothesis that it was a "generalist specialist, a very Sapiens niche" that give our species the ability <<to rapidly came to dominate the Earth’s diverse continents and environment.>> <<...our species not only colonized a diversity of challenging environments, including deserts, tropical rainforests, high altitude settings, and the palaeoarctic, but also specialized in its adaptation to some of these extremes.>> (see Biblio 2)

How did H.S. develop this unique "ecological ability"? According to the authors, the main factors were (see Biblio 2):
  • "extensive cooperation between non-kin individuals"
  • "accumulating, drawing from, and passing down a large pool of cumulative cultural knowledge, in material or idea form, may have been crucial in the creation and maintenance of the generalist-specialist niche by our species in the Pleistocene"  

From prehistory to history 

In a series of previous posts (see Biblio 3) I have presented the "revolution" that start the human civilization and cross the border from prehistory to history around 10000 B.C. My conclusions were similar. This non-genetic "boom" was produced by extensive cooperation and better distribution of knowledge that were both made possible by the first large communities of humans. 

In fact, from its appearance, Homo Sapiens was clearly superior from this point of view to previous and co-existent human species. Because of that was able to "conquer the Earth" and make others extinct. 

Still, for almost 200000 years, the human culture makes too few progress, because this "very sapiens niche" (see Biblio 2) cannot manifest well in small groups of individuals. Only with the first large communities around 10000 BC, the cognitive & collaborative potential of Homo Sapiens was really used.   

Bibliography and References

[Biblio 1] 
A. Laziness May Have Driven Homo Erectus to Extinction, By Yasemin Saplakoglu, Staff Writer,  August 10, 2018  
B. Acheulean technology and landscape use at Dawadmi, central Arabia, by Ceri Shipton, James Blinkhorn, Paul S. Breeze, Patrick Cuthbertson, Nick Drake, Huw S. Groucutt, Richard P. Jennings, Ash Parton, Eleanor M. L. Scerri, Abdullah Alsharekh, Michael D. Petraglia. PLOS,  Published: July 27, 2018
[Biblio 2] 
 A. Homo sapiens developed a new ecological niche that separated it from other hominins, July 30, 2018
 B. Defining the ‘generalist specialist’ niche for Pleistocene Homo sapiens, Patrick Roberts & Brian A. Stewart, Nature Human Behaviour; volume 2, pages542–550 (30 July 2018)
[Biblio 3]  - Previous posts related to human evolution and behavior pattern

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