what we know about the eight species with which we have lived for millennia

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Several recent studies have shed light on the times when homo sapiens was not the only human species on Earth. one of these jobs tells us a story that occurred near our borders, in the southeast of France, where Neanderthals and Sapiens alternated more than 50 millennia ago. The study has led us to the question, what happened to those other human species that did not reach our days?

the other human species.
we don’t know exactly how many species of the genus homo have populated the earth in the last two million years. Precisely drawing the evolution of any genre is a very difficult task, the remains that remain are limited and with them we must cover periods of time orders of magnitude greater than those we handle in our day to day. Fortunately, our present understanding of genetics and dating is much more advanced than when we began this quest.

Neanderthals (homo neanderthalensis), Denisovans, H. rhodesiensis, H. naledi, H erectus, H. floresiensis, H. luzonensis and the Red Deer Cave people are the species we know to have coincided chronologically with homo sapiens. Many others became extinct before our arrivalsuch as homo antecessor or homo ergaster.

The fossil traces of these species are scattered throughout the territory of Africa and Eurasia (or Eurafrasia as the great landmass is also known), reaching places as remote as the Philippine Islands.

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expansion of homo sapiens.
The first homo sapiens appeared about 300,000 years ago (300 ka), in Africa, but anatomically modern humans (AMH) would still take time to appear, about 195 ka. The first human remains found in Europe date from this first period, although it was a short and localized stay.

Although their departure from the African continent is confirmed in the first millennia after their appearance, it is estimated that they reached Europe between 43 and 45 ka ago. Homo sapiens arrived in Australia 65,000 years ago, millennia before leaving a permanent trace in Europe.

coexistence in Europe.
During the first 150 millennia of homo sapiens, Europe was a Neanderthal territory and it seems that modern human expansion forgot about this territory, due to environmental conditions rather than the presence of Neanderthals. However, we do not have reliable evidence of their coexistence. An example of this is the 7,000-year gap observed in a cave in Malaga used by both species.

Genetic testing tells another story. Contemporary humans carry within us a 2% of genes we owe to Neanderthals (somewhat less in people of African origin). They are not the only species with which we share genes. The study of the French cave, Grotte Mandrin provides evidence of the arrival in Europe of modern humans about 10,000 years earlier than previously thought.

The team found archaeological remains corresponding to various stages of human occupation in the cave. The surprising thing about the discovery was that, among the layers in which they found Neanderthal remains, they found others belonging to modern humans.

A tooth and several tools.
This conclusion was based on a human molar and various tools that would be made by modern humans and would be about 54,000 years old. Ludovic Slimak, co-author of the study explained that “with Neanderthal tools, each tool is a creation. If you look at 1,000 tools, each one will be completely different. But with a homo sapiens industry… it is super standardized and regular.”

The researchers thus drew a chronology of the cave in which Neanderthals first resided, followed by a brief occupation of the cave by Sapiens. This followed in turn by another 12,000 years of Neanderthals before the return of Sapiens.

The study affects our idea of ​​the extinction of other humans.
we are not sure about what caused the demise of the human species that preceded us and it is possible that each of them disappeared for different reasons in different places and times. There are some causes with which the experts speculate and that may have had greater or lesser weight depending on the case.

Diversity of theories.
The fact that all species except one disappeared and cases such as the (more or less) rapid succession between Neanderthals and Sapiens led to the hypothesis that the latter were the main cause of the extinction of the rest of the species. Modern humans would have emerged victorious from a competition for scarce resources. The finding in France extends the time during which both species coexisted, subtracting certain relevance to this theoryalthough it is far from being able to rule it out.

A demographic trap.
Demographic factors could also be related. In the case of Neanderthals, the idea has been postulated that their population was simply reduced until a time came when natural demographic fluctuations themselves lead the species to reach a critical point of no population return. From this point on, inbreeding hindered reproduction, leading the species to a negative demographic spiral.

If this happened with the Neanderthals, a species settled across a continent several hundred thousand years old, it is possible that other species also fell into the same demographic trap.

The changes in the weather.
maybe the prime suspect, however, be the change in weather conditions. The alternation between ice ages and warm periods has undoubtedly had an effect on the migratory movements of humans, allowing some migrations and forcing others.

The climatic hypothesis is perfectly compatible with other hypotheses. Species that coexisted under certain climatic circumstances may end up competing when these change, for example. Similarly, glaciers and islands formed after melting can isolate communities from one another, forming demographic traps.

Extinction or assimilation.
One theory remains, the asimilation. According to this idea, species such as Neanderthals or denisovans they could not be considered extinct thanks to the stronghold of their remaining genetics in ours. This would imply that they would not have become extinct but rather would have evolved. Becoming us, our ancestors. This debate is perhaps, however, more philosophical, related to what is the “being” of a species, and how we determine which ones live and which ones do not.

Image | Thilo Parg CC-BY-SA-4.0

Several recent studies have shed light on the times when homo sapiens was not the only human species on Earth.…

Several recent studies have shed light on the times when homo sapiens was not the only human species on Earth.…

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