Even if modern man did not have any advantage over the Neanderthals, their end was known in advance when modern man spread in Europe, according to a study led by an Israeli Ph.D. at Stanford University
The living evidence of Neanderthal man is now found in the human genome. Scientists are convinced that between one percent and five percent of the genomes of modern Europeans and Asians contain Neanderthal DNA - a reminder that for a period of about 15,000 years (in Europe; in the Middle East it is tens of thousands of years) modern humans and Neanderthals existed side by side in Europe and mated with each other until The complete disappearance of the Neanderthals 38,000 years ago.
A study by two Stanford University researchers published Tuesday in Nature Communications also takes into account a scenario in which modern humans and Neanderthals had no advantage over each other, and finds that the Neanderthals would have gone extinct anyway.
The researchers, Oren Kolodani, postdoctoral research fellow and Prof. Markus Feldman wrote in the article: "Our simple model indicates that back-migration from Africa to the Levant and Europe - even at a low intensity - would have been sufficient to cause the replacement of Neanderthals by modern humans, even if both species had not A selective advantage of one over the other, and regardless of possible differences in population size between the two species," the researchers write.
Feldman is the winner of the Dan David Award from several years ago in Evolution. Kolodani graduated with a master's degree at the Hebrew University and a doctorate at Tel Aviv University. In an interview with the science website, he explains:
"We can evaluate the strength of the selective processes while evaluating the rate of mutation propagation. The faster the mutation spreads, the higher the selection coefficient. If we translate the prevailing assumption, that modern man had an advantage, into this methodology of evaluating selective advantage, this means that if the replacement of the Neanderthals was fast, the selection coefficient of modern man was necessarily very large, and if it was slow then the coefficient was small. We challenge this assumption and argue that it is correct to first consider the simpler possibility that Neanderthals did not fall short of modern humans in their fitness. According to our model, whenever a group, modern or Neanderthal, wanted to expand, it had to take over territory. For this, it was necessary to compete with a group that was already sitting there, whether it was Neanderthals or moderns. Sometimes moderns replaced Neanderthals, sometimes Neanderthals replaced moderns, and usually Neanderthals replaced other Neanderthals and moderns replaced other moderns (just as has continued to happen throughout history). It is also quite possible that alliances were sometimes formed between modern humans and Neanderthals against other groups.
But unlike the Neanderthals who stayed in Eurasia and did not migrate to Africa, modern humans crossed this land bridge again and again, meeting Neanderthals again and again, until finally when the last Neanderthal died, there was no genetic pool from which to preserve the species, unlike modern man who kept coming his friends, Even if at a low rate, and fill the lines.
"In lectures, I imagine James Bond fighting with his nemesis on the roof of a moving train. They move back and forth quite randomly across the roof. Eventually one of them will fall. In the end only one will remain on the roof, the question is who will it be. Now let's add another assumption to the situation - that James Bond every time he falls manages to hold on to something and climb back to the roof. In the end, with such an assumption, he must win. Once the nemesis falls, it's game over." Dr. Kolodni explains.
Maybe modern humans simply caught the Neanderthals in a weak period?
"Quite a few studies have tried to explain things this way: the Neanderthal populations grew and shrunk their suits because of climate changes, and by chance some climatic event occurred that caused them to weaken and then modern humans gave the final blow. There is no conclusive evidence of this. We do not see a huge climate change in the short time before the extinction, nor evidence of an epidemic. Our explanation is a neutral explanation that does not assume any external factors for which there is no convincing evidence, but only takes what we know with a high degree of certainty about the migration patterns at that time: repeated migration of moderns from North Africa, and no migration of Neanderthals in the opposite direction. Our simple model, based only on this, is enough to explain the disappearance of the Neanderthals. This does not necessarily rule out the previous explanations: it is possible that the modern man had an advantage over the Neanderthals and perhaps also climatic changes harmed them. But the model shows that even if not, the result would have been the same."
Continuing the research, Kolodani began in collaboration with Prof. Arela Hubers, head of the Institute of Archeology at the Hebrew University and an expert on the period, to investigate what happened in the Levant where extinction did not occur for tens of thousands of years when the two species seem to have lived side by side. At that time, did Neanderthal humans occasionally arrive from Europe to fill the ranks?
23 תגובות
A. Ben Ner
I agree with you about non-extinction. Regarding the language, less so.
To this day there are groups of people whose way of life has not really changed since the Neanderthal period. Their way of life is not so far from that of the great apes. So language ability is probably not the reason for our cultural development.
for miracles
The assertion that the Neanderthals are extinct may be wrong. It is more correct to say that it has been assimilated into modern man. After all, from the beginning these were not different and separate species but two varieties of the same species, (like for example Jerusalemites and Tel Avivites, yes?). The vision - they multiplied with each other.
Regarding the development of the chin. Well, it is not just a small protrusion of the lower jaw, but a change in the entire structure of the lower jaw, the cavity of the throat, the tongue, and the vocal cords in complex ways that allow the development of speech.
Regarding the contribution of speech to human evolution, see below a basic discussion on the subject from Wikipedia:
https://he.wikipedia.org/wiki/%D7%90%D7%91%D7%95%D7%9C%D7%95%D7%A6%D7%99%D7%94_%D7%A9%D7%9C_%D7%94%D7%A9%D7%A4%D7%94#.D7.AA.D7.A4.D7.A7.D7.99.D7.93_.D7.94.D7.A9.D7.A4.D7.94
An idea, a hypothesis
A. Ben Ner
I'm not sure we're talking about the same thing. "Chin" is a bulge in the lower jaw bone. It has a certain effect on speech, because it enlarges the oral cavity. But, from here until it has an impact on the success of the human race in the world, the distance is great. If you think the chin is as important as the legs, then we are probably talking about different things.
Saying that evolution is a hypothesis is like saying that the sun is a hypothesis. What does this statement contribute?
Let me give you another idea for the extinction of the Neanderthals. The modern man has two unique qualities. The first is the tendency to migrate and change one's place of residence (I am not talking about seasonal migration). The second is the ability to adapt to different food and environmental conditions. Neanderthals were not like that.
Now, in the common habitat of humans and Neanderthals, there is a shortage of food due to a long drought. The response of both sexes was the same - raising fewer children. The result - the people who lived in other places remained.
Now, when I read the article again, it seems to me that they are saying something very similar...
for miracles
To say that, as you say, "the effect of the chin on speaking is not great", is roughly like saying that the effect of the legs on walking is not great.
Regarding your claim as if "the evolutionary advantage of language is your hypothesis" means two things:
First, with proper modesty; I would be happy to be the creator of this interview, however, it is not the fruit of the Gothic, I read it in many different places and to the best of my memory, I first read it about 50 years ago in a booklet published by IBM on the brain and evolution edited by the late Zvi Yanai and since then in many other articles.
Second, as for the whole evolution interview, it is generally nothing but an omission. Not (only) mine but of many better and wiser than me. True, it has evidence and support for most of it, but nevertheless it is nothing more than a conjecture, and will remain so forever, unless... it is proven to be a mistake.
A. Ben Ner
The effect of the chin on speech is not great, and in any case - there is no basis for the claim that this is its advantage. Another explanation is gender selection (Teyer and Dobson). And another explanation claims that it is not a match at all, but a by-product of the mechanics of the development of the human skull (Leventin).
You are right that our ability to speak depends on many factors, the most important are areas of the brain (Broca, Wernicke and others), after that the structure of the voice box, the muscles of the tongue and face and so on).
The evolutionary advantage of language is your hypothesis, not based on what we really know. Note - evolution is not a competition between species. Evolution is (the result of) competition between individuals of the same species. Beyond that - we do not know which of the hominids had the ability to speak and which did not.
I agree that language gives us a huge advantage, and is one of the few things we have that no other species has (ok ok, chin too….). But there is no justification for the claim that it advanced us evolutionarily. There are animals with social lives no less sophisticated than ours.
for miracles
In my opinion, we definitely know what is the distinct evolutionary advantage that the chin gives to man, and that is man's sophisticated ability to speak compared to other animals, which is man's most significant evolutionary advantage.
At the same time, it is important to note that the human ability to speak involves the development of additional systems such as: the speech center in the brain, the refinement of the voice production system, the adaptation of the tongue and the respiratory system, and probably other systems.
To the question of why only man has developed such a sophisticated speech system, the answer is that the speech system gives man such a great advantage over other animals, an advantage that allows man to exterminate ahead of time, any development of a sophisticated language in others while it is at enmity and thus prevent competition Evolutionary about speech as an evolutionary resource.
for miracles
You are right about the jaw muscles. I assume then that in the shape of the modern skull (vertically flat)
The chin has an additional structural support for the lower jaw. The matter deserves an engineering test if it has not already been done
Such as part of the confirmation of the theory of evolution that guides us that there is a reason for biological structures and organs
In B.A.H. and I see no other reason for the existence of the chin.
for miracles
You are right about the jaw muscles. I assume then that in the shape of the modern skull (vertically flat)
The chin has an additional structural support for the lower jaw. The matter deserves an engineering test if it has not already been done
Such as part of the confirmation of the theory of evolution that guides us that there is a reason for biological structures and organs
In B.A.H. and I see no other reason for the existence of the chin.
Benjamin May
We don't know why humans, and only humans, have chins. Our jaw muscles do not attach to the chin, but to the back of the jaw bones.
It seems that there is a consensus among researchers that modern man and Neanderthal interbred and lived in close proximity to each other. It can also be assumed that they spoke and understood each other. The conclusion that emerges from this is that it is not about two different species of man but perhaps two different varieties of the same species. Why is this similar, for example from the field of poultry, a stork and an eagle cannot mate with each other, the genetic difference between them is too great. On the other hand, a white stork and a black stork can mate and produce fertile offspring(!). The genetic variation between them is very little.
Therefore, the conclusion is that we are not the descendants of modern man only, but a fusion and hybridization (hybridization) between these two varieties of the human species, modern and Neanderthal.
Oops...and of course I meant to write "....they are also an answer to the question of
A. Ben Ner regarding the departures from Africa and returns to it.
for miracles
What is written in the article is reasonable to me, even in light of the fact that they were not found
Many intentional hits on Neanderthal skeletons (if any), if there was a premeditated kill
of populations I assume that there were evidence of this and of course the Neanderthal genes
that modern man outside of Africa carries. Note that the number of genes varies
Among different populations, there are even populations that carry Denisovan genes, one can assume
that there were quite a few sexual relationships between the different human species (and therefore also survived enough
evidence of this, since not every sexual encounter results in a surviving offspring that leaves generations behind)
When the larger population (modern man) passed on more of its own genes
For future generations, therefore, the rest of the human species disappeared, just like the domestic cat "raises"
the swamp cat
The larger numbers of modern humans are also an answer to the question of
A. Ben Ner regarding the emigration from Africa to it. More sons means more pressure on populations
To wander on the one hand - and also the ability to realize a journey of those who are not satisfied - on the other hand.
It should also be remembered that not all those leaving Africa went to Europe, so it is quite clear that the modern man
He is literally a survival success compared to the rest of the human species, which is reinforcing
the claim about the genetic disappearance of the rest of the human species.
You are wrong about the forehead. The chin is special to the modern man as an anchor for the jaw muscles,
The rest of the face was flattened vertically because of the position of the chin.
Benjamin May
I think you meant the forehead, not the chin.
Benjamin May
I think I misunderstood you. Do you get what the article says?
for miracles
In man as a social tool builder, modern or Neanderthal, intelligence is the significant survival factor.
In these crocodiles the jaws and the size and in other species the camouflage, the speed or the speed of reproduction are the significant survival factors.
This is of course the survival of a species or species and not a single case, of a genius who was born blind.
The theory claims that the migration of modern man from Africa to Europe is the cause of the extinction of the Neanderthal man, but avoids explaining why modern man migrated to Europe while the Neanderthal avoided migrating to Africa. There is a lack of symmetry here that requires an explanation, which is actually the basis of solving the problem. Why did the Neanderthal freeze in his colonies in Europe while the modern man conquered new territories and expanded his distribution from Africa to Asia, Europe and Australia?
The theory does not address this.
In Thailand and Africa they eat monkeys. Why not think of a gastronomic solution that the Neanderthals disappeared because they ate them. They have already found caves that contained skeletons of Neanderthals and Homo sapiens.
Please respond gently and consider that I am before lunch.
Good Day
Yehuda
Benjamin May
I think you have a hidden assumption - a more intelligent species has more survivability. If you look at nature, you will see that this is not the case. And if you look at the modern man - then the situation is quite the opposite...
There is one matter that for some reason has disappeared from researchers (or at least I haven't read about it..). The shape of the skull.
The skull of the modern man includes a chin and is therefore different in shape compared to the angular skull
and the relatively elongated of the previous human types. This is how a small and light skull can accommodate
On the one hand, a big brain and on the other hand, to pass easily through the cervix during birth (everything is relative, of course).
Ultimately the shape and volume of the skull determine the chances of survival at birth and size
The brain, which is the most important organ for the survival of the human species - that is, the chances of survival in adulthood.
Therefore, there is a possibility that Homo sapiens came in much larger numbers and simply "drown" you
The Neanderthals in the "genetic ocean" - as can be understood from the article.
A flat-faced skull like the modern man also allows for an elaborate communication of expressions
An interior and therefore a more sophisticated society - but that's another story...
Can you imagine how many moderns or Neanderthals there were on the whole planet? How many lived? Twenty million details? Fifty million details? In most of the world the density was so low that to get from group to group you had to walk for days. Including in fertile and pleasant areas for living. And always a group that was in conflict and was at a disadvantage could migrate to more distant areas. Maybe they interbred so much that the Neanderthals just disappeared into the moderns?
The most intellectually exciting dream in my lifetime that could happen is the cloning of a Neanderthal man. But it is doubtful that the evil moral laws of our time will allow such a scenario to happen.
If in any case the Neanderthals were to disappear then we Homospians are not to blame. Thanks to the scientists for the acquittal of genocide. I am convinced that the researchers are right.