Were other humans the first victims of the sixth mass extinction?

This article does not afford the possibility of multi-regionalism in Africa:

https://www.eupedia.com/forum/threa...-Populations-across-Africa-Why-Does-It-Matter

Highlights


The view that Homo sapiens evolved from a single region/population within Africa has been given primacy in studies of human evolution.

However, developments across multiple fields show that relevant data are no longer consistent with this view.

We argue instead that Homo sapiens evolved within a set of interlinked groups living across Africa, whose connectivity changed through time.

Genetic models therefore need to incorporate a more complex view of ancient migration and divergence in Africa.

We summarize this new framework emphasizing population structure, outline how this changes our understanding of human evolution, and identify new research directions.

We challenge the view that our species, Homo sapiens, evolved within a single population and/or region of Africa. The chronology and physical diversity of Pleistocene human fossils suggest that morphologically varied populations pertaining to the H. sapiens clade lived throughout Africa. Similarly, the African archaeological record demonstrates the polycentric origin and persistence of regionally distinct Pleistocene material culture in a variety of paleoecological settings. Genetic studies also indicate that present-day population structure within Africa extends to deep times, paralleling a paleoenvironmental record of shifting and fractured habitable zones. We argue that these fields support an emerging view of a highly structured African prehistory that should be considered in human evolutionary inferences, prompting new interpretations, questions, and interdisciplinary research directions.

https://www.cell.com/trends/ecology...m/retrieve/pii/S0169534718301174?showall=true




Our fractured African roots

While it is widely accepted that our species originated in Africa, less attention has been paid to how we evolved within the continent. Many had assumed that early human ancestors originated as a single, relatively large ancestral population, and exchanged genes and technologies like stone tools in a more or less random fashion.

In a paper published in Trends in Ecology and Evolution this week, this view is challenged, not only by the usual study of bones (anthropology), stones (archaeology) and genes (population genomics), but also by new and more detailed reconstructions of Africa’s climates and habitats over the last 300,000 years.

One species, many origins

“Stone tools and other artifacts – usually referred to as material culture – have remarkably clustered distributions in space and through time,” said Dr. Eleanor Scerri, researcher at the Max Planck Institute for the Science of Human History and the University of Oxford, and lead author of the study. “While there is a continental-wide trend towards more sophisticated material culture, this ‘modernization’ clearly doesn’t originate in one region or occur at one time period.”

Human fossils tell a similar story. “When we look at the morphology of human bones over the last 300,000 years, we see a complex mix of archaic and modern features in different places and at different times,” said Prof. Chris Stringer, researcher at the London Natural History Museum and co-author on the study. “As with the material culture, we do see a continental-wide trend towards the modern human form, but different modern features appear in different places at different times, and some archaic features are present until remarkably recently.”

The genes concur. “It is difficult to reconcile the genetic patterns we see in living Africans, and in the DNA extracted from the bones of Africans who lived over the last 10,000 years, with there being one ancestral human population,” said Prof. Mark Thomas, geneticist at University College London and co-author on the study. “We see indications of reduced connectivity very deep in the past, some very old genetic lineages, and levels of overall diversity that a single population would struggle to maintain.”

An ecological, biological and cultural patchwork

To understand why human populations were so subdivided, and how these divisions changed through time, the researchers looked at the past climates and environments of Africa, which give a picture of shifting and often isolated habitable zones. Many of the most inhospitable regions in Africa today, such as the Sahara, were once wet and green, with interwoven networks of lakes and rivers, and abundant wildlife. Similarly, some tropical regions that are humid and green today were once arid. These shifting environments drove subdivisions within animal communities and numerous sub-Saharan species exhibit similar phylogenetic patterns in their distribution

The shifting nature of these habitable zones means that human populations would have gone through many cycles of isolation – leading to local adaptation and the development of unique material culture and biological makeup – followed by genetic and cultural mixing.

“Convergent evidence from these different fields stresses the importance of considering population structure in our models of human evolution,” says co-author Dr. Lounes Chikhi of the CNRS in Toulouse and Instituto Gulbenkian de Ciência in Lisbon.“This complex history of population subdivision should thus lead us to question current models of ancient population size changes, and perhaps re-interpret some of the old bottlenecks as changes in connectivity,” he added.

“The evolution of human populations in Africa was multi-regional. Our ancestry was multi-ethnic. And the evolution of our material culture was, well, multi-cultural,” said Dr Scerri. “We need to look at all regions of Africa to understand human evolution.”

http://www.shh.mpg.de/1007846/human-evolution
 
it is quite simple
imagine the whole earth is empty except for a healthy young man and a lady
imagine there is enough food and there are no diseases
in a 600-700 year timespan there will be some 7 bijlon people on earth again, like today
if there is no natural selection or birth control, those who want to survive have to kill the others
or ban them to places on earth that have no resources to let them survive
 
That modern man evolved from several source populations should not be unexpected. We know that modern humans interbred with Neanderthal and Denisovians from time to time so it's no great leap to expect contact between other, earlier homo types. Any woman should be able to tell you that the sexual habits of men are simply awful!

The article also implies, or says out right, that modern man killed off these early men in a "sixth mass extinction" (a crime appended to that of killing the Ice Age mammals and today's rain forests), but it seems to me that the salient point is that they all occupied the same ecological niche; success for one group entailed decline for the others. Archaic men disappeared because they could not successfully compete with modern humans.
 
Or, better yet. Nobody killed anybody, nor drove anyone into extinction. We all just interbred with abandon . . . any body, any species, any place . . . with all our offspring evolving to become modern humans.
 

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