HOW & WHY (SOME) NEANDERTHAL TRAITS WERE OUTBRED:
Abstract: Considering what is known about Neanderthals’ physiology, especially their mass, and brain development, they were at a reproductive disadvantage relative to the more gracile and less energy demanding Homo Sapiens they met. In combination with quasi-extinction events, and exponential demographic recovery, the dilution of Neanderthals’ genetic traits, except when vastly superior, was thus ineluctable, as observed.
So it’s not the fittest traits which survived Neanderthal-Sapiens interbreeding, but the most easily reproduced traits. This generalizes to other evolutionary situations, and provides with a new mechanism for the machinery of evolution.
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Many racist theories fester around the “disappearance” of Neanderthals. The latest one, from Oxford University, claims that Neanderthals’ big, beautiful eyes, and their big muscles caused their demise: Neanderthals were too busy looking at things, while flexing their muscles. The “idea” is that larger eyes would have crowded the Neanderthal brain out, making them relatively stupid. How stupid can Oxford get? In particular eyes made them incapable of having social groups as large as those of Homo Sapiens Sapiens.
Big Eyes Do Not Kill
Sapiens girl on the left, Neanderthal girl on the right (reconstitution published in Science Magazine a few years ago).
I have long argued that the strength of democracy came from having many brains working in parallel. There is little doubt that larger social groups bring a higher cultural intelligence, hence higher individual intelligence. So I agree about that bit of logic. Yet, ironically, to reach the conclusion that Neanderthals’ social group were less numerous, the simple fact that Neanderthals were bigger, is enough. There is no need for hazardous demeaning allegations about Neanderthals’ brains.
That big eyes made Neanderthals stupid contradicts some facts that were thought to be established:
1) Sapiens Neanderthalis’ brains were significantly larger to start with. See Wikipedia.
2) Many very clever Homo Sapiens Sapiens have small brains. Famously Anatole France, an intellectual, had only a 1,000 cubic centimeters brain. Homo Floresiensis, the “hobbit” species living on the island of Flores, Indonesia, until it was wiped out recently, was extremely intellectually capable, although it had really small (and completely different) brains.
3) In the Middle East, Neanderthals and Sapiens went back and forth through the same large caves over 50,000 years. So whatever happened, it was not in evidence for 50,000 years.
So, of course, I have my own theory. That’s what philosophy is all about: trying to guess what really matters most, and how that most significant data logically articulate. Then scientists, politicians and writers can swoop, figure out the details, and attribute themselves the glory.
What could have happened by around 28,000 years ago that caused the demise of Neanderthals? At the time, the last fierce glaciation was gaining ground. (It reached its maximum 25,000 years ago.) Some have argued, absurdly, that the Neanderthals could not take it. That’s beyond silly, as Neanderthals had evolved, from half a million years ago, precisely to handle extreme cold.
Neanderthals were stocky, powerful, and they had thrived through hundreds thousands years of glaciation, mostly on a meat diet, hunting big game. But they also knew how to cook plants, and eat them.
27,800 years ago, Cave Bears were exterminated. That huge animal who lived in caves, primed real estate Sapiens Sapiens and Neanderthals craved for. Could the disappearance of Cave Bears be logically linked to the disappearance of Neanderthals? Yes. That’s a consequence of my theory. More advanced technology played a direct role. So did size: Cave Bears disappeared, because they were larger than European Brown Bears (called Grizzlies in America), according to the mechanism below, differential exponentiation.
How did men kill Cave Bears? With technology. We do not know exactly what weapons men had at their disposal. However, technology had improved, and kept improving. Recently it was found that Sapiens Sapiens (Homo SS; I hope one gets the joke) in Africa had invented bows and arrows 80,000 Before Present (BP). (About 60,000 years earlier than previously thought!) Before bows and arrows, the propeller had been invented, and was used in Europe. The propeller took advantage of angular momentum to send a sort of mini lance further and stronger than by hand.
Why did the Neanderthals and Denisovans (another human species from Central Eurasia) lose their edge? Advancing technology is the obvious answer. When technology of clothing and weapons was sufficiently advanced, the physiological advantage that the Neanderthals genetically had, disappeared. Homo Sapiens Sapiens could thrive just as well through winter.
At that point, Homo Sapiens Sapiens from Africa could be as successful as the Neanderthals through the freezing wastelands of Europe. OK.
But the Homo SS outbred the Neanderthals, so they became genetically more successful. How do I explain that?
Simple. However, the explanation involves the exponential function, the same function found all over, and that the mathematician Rudin called “the most important function in mathematics”. The exponential also explains the plutocratic phenomenon, and that is why it’s so dangerous. The exponential always rules extinction events, that’s why one day a species is all over, like the American Pigeon, or the Tasmanian Tiger, and the next day, it’s gone.
So visualize this. Neanderthals were bigger than Homo SS, just like the Polar Bear is bigger than the Black Bear. Bigness is an adaptation to cold. Southern Europe’s Brown Bears are smaller than those found in Kamchatka, or Alaska (also known as Grizzlies: the Grizzly is an emigrated European Brown Bear!) Bigger makes warmer inside. That’s why the most massive animal that ever was, the Blue Rorqual, at up to 180 tons, is nearly twice the mass of the largest dinosaur (it’s not just that it’s floating, but also that water is cooler than Jurassic air, I hold).
To simplify, let’s use a bit of exaggeration (that’s reasoning by exaggeration, one of my preferred tactic of thought; the one humor exploits, and why joking helps thinking). Let’s assume Neanderthals were twice more massive than Homo SS (certainly, in the average, Cave Bears were twice the mass of Brown Bears).
Now let’s consider an habitat where Homo SS and Neanderthal bands roamed. They will tend not to mix, for obvious racist reasons. The racial hatred between Neanderthals and Homo SS has got to have been colossal. People who look too different are not even sexually attracted to each other (and where Neanderthals and Homo SS were in contact in the Middle East, for 50,000 years, there is no evolution of an interbred species, an indirect proof that there was no love lost there!)
The density of human mass is going to be roughly the same all over, because that density depends only upon the resources available (mostly meat on the hoof, and fur in burrows in glaciating conditions).
Thus, there would have been apartheid. But the Homo SS would have been twice more numerous, where they reigned (from my assumption of twice the mass). So now graft on this a catastrophe; a drought, a flood, a very tough winter, a volcanic super disaster, whatever. The climate was highly variable, starting about 40,000 years ago, just when Homo SS appeared. Some have stupidly argued that Neanderthals were too stupid to adapt to this changing circumstances. Like this paralyzing stupidity struck them just when Homo SS were around. My explanation is more subtle.
After a catastrophe in said habitat, say one of these numerous habitat in Europe isolated by glacial mountain ranges, or seas and lakes, most of the human population would be wiped out, Homo SS, just as Neanderthals. There would tend to be always a small remaining population, because the greatest limit on man is man himself: as a population gets wiped out, resources rebound, and life of the survivors tend to get much easier (that’s what happened in Europe after the Black Death of 1348 CE; if nothing else, survivors could ask for higher salaries from their plutocratic masters, and they did).
So say 90% of the population of the habitat was wiped out. As suddenly resources are no limited, the human population will rebound exponentially. The equation is: N(t) = N(0) exp(Rt). “R” is the “Malthusian” parameter, the rate of growth. Now it’s going to require twice the resources to feed a Neanderthal to sexual maturation (under our outrageously simplifying assumption that Neanderthals are twice the mass). Thus one may assume that R(Homo SS)/R(Neanderthal) is 2. The end result is that the quotient:
Number Homo SS/ Number Neanderthal = A exp(2t). (Where A is the ratio of the populations H SS/Neanderthal after the catastrophe.)
Thus the population of H SS would exponentially grow relative to that of the Neanderthals, resulting in a quick extinction. And in no way this is happening because Homo SS were superior. Just because they were more gracile.
Another factor is that Sapiens had a larger reservoir of population to the south of Europe and the south of North Africa, in sub-tropical Africa, so Sapiens could come up from the south in great numbers, especially when the climate was cool enough for the deserts, including the Sahara to be covered with savannah-park… an environment for which more gracile Sapiens was more suited, and in which the preceding argument about mass of the body would apply.
It is known that the climate fluctuated violently where Neanderthals lived and had evolved for. The consequence was potentially lower population expansion when exposed to invasion by Sapiens whose genetic reservoir (the South) was mostly a refuge from said wild temperature fluctuations (so, although the climate would massacre the Neanderthals in the north, the Homo SS in the south would be ready to expand much more, from a larger population, and thus expand into the north; this is a question of comparing two exponentials again, the one starting from a larger population grows faster) .
When the temperature fluctuated up, Sapiens populations could invade relatively
recently more sparse Neanderthal habitat, which had brought Neanderthals to a near-extinction event. This, accentuated by interbreeding, would have led to quick Neanderthal gene replacement (replacement, because of interbreeding).
Why didn’t the replacement of most Neanderthal genes by Homo SS genes happen before? Because the advancement of technology. That was partly led by Neanderthals, but whatever Neanderthals invented was transmitted to the larger Homo SS population, and made Neanderthal genetic advantage redundant. Moreover, the relatively smaller Neanderthal population, all other mental things being equal, would have been exposed to the Tasmanian Effect (See my enormous essay, the Tasmanian Effect, which considers various traps small populations can fall into, among other mental, and thus demographic disasters).
On top of that, technological advances insured that life was becoming possible for Sapiens in Eurasia. As Sapiens encroached, Neanderthals kept on living in more difficult, fluctuating places, thus propagating the extinction.
Hence the mystery of the evolution of contemporary man is smoothly explained. Just a bit of math. QED.
Europeans & Asians: Not Just African
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Patrice Ayme
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Note 1: what of the mentally deliquescent and racist article in the Proceedings of the Royal Society? First, they sank so low as to “using orbit size as a proxy, that Neanderthals had larger visual systems than contemporary AMH [Anatomically Modern Humans]“. That’s about as intelligent as saying that, because special forces use night vision goggles, they have got to have bigger visual systems.
The main woman author also found the same physiological feature, bigger eyes, in the past, about people presently living at high latitude. She contentedly asserted that, because light levels are lower in the north, people living in the north (40,000 years at least for Homo SS) have bigger eyes. Amusingly, she did not draw, in that case the conclusion that Norwegians and the English are therefore more stupid. Somehow, though, in her lack of smarts, she applies that controversial reasoning to Neanderthals. Does she have giant eyes?
Seriously the Oxford study rests on a central fact that contradicts one of established facts about Neanderthals. Indeed it claims Neanderthals’ brains were not any larger than Homo SS.
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Note 2; what catastrophes am I talking about? Well the climate fluctuated wildly, to start with. Second, A Campanian ignimbrite volcanic super-eruption around 40,000 years ago, followed by a second one a few thousand years later, certainly crashed Neanderthal populations (based on logic, and evidence from Mezmaiskaya cave in the Caucasus. Mitochondrial DNA analysis of a specimen there is C14 dated 29,000 years BP, one of the latest living pure Neanderthals). After such a catastrophe, the exponential rebounds of populations would have advantaged Homo SS, as explained above.
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Note 3: OK, I exaggerated with the mass ratio. (Mathematicians often do this, considering an exaggerated case to understand the mean, through the tails.) But the real mass ratio would be aggravated because, Neanderthal was built in such a way, relative to gracile Homo SS, that they consumed more calories per day (some paleontologists have come up with 300). So there is no doubt that the effect above will play a role, even if the mass ratios were not as bad. Notice the mechanism above would tend to extinguish the Neanderthal traits that were most characteristic of the subspecies.
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Note 4: A preferred trick of Neanderthals’ haters is to exhibit Archaic Neanderthals‘skulls, and compare them to those of modern men. The skull of an Archaic Neanderthal of 400,000 years ago should not be compared to a modern human, less than 40,000 year old! All the more since Neanderthals’ brain size augmented faster than the brain size of Homo Sapiens Sapiens.
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Note 5: NEAR-EXTINCTION THEORY: WHY DINOSAURS DISAPPEARED: SAME MATHEMATICS! Part of the mechanism above generalizes for other species in competition. It provides with a disappearance mechanism after ecological turbulence, according to species’ ecological footprint. The reasoning can be generalized to other species’ extinctions. Let’s recapitulate the preceding, while generalizing it:
1) it is hard to transform a near extinction event into total eradication (see the Black Plague of 1348 CE). Indeed, the more the extinction, the easier it gets for the survivors, as resources rebound (this is similar to the famous lynx-rabbit oscillation).
2) However, larger animals (Neanderthals, DINOSAURS), or animals with a higher metabolic load (Neanderthals) are going to be to be left behind exponentially, during the rebound phase.
In the case of Neanderthals the periodic catastrophes could have been of climatic origins (waves of cooling, warming and unstable climate as the earth underwent various tipping points, one way or another, into the occasionally severely glaciated period between 60 K and 11 K BP. A severe volcanic catastrophe or two would have added near extinctions episodes.
In the case of dinosaurs, the massive Deccan eruptions, over millions of years, culminated with the most acute episode, more or less contemporaneously with a massive asteroid impact (!). According to the exponential extinction theory above, the back and forth of near extinctions would have put a severe extinction pressure on the dinosaurs and the like, as smaller, more efficiently active mammals and birds would have put huge pressure on dinosaurs and flying reptiles (same in the sea).
T Rexes had to grow by three kilograms a day, for years (same for Triceratops, etc.). A huge energetic demand on the land… While smaller mammals could go through generations, adapting to changing circumstances…
By eating dinosaurs’ eggs to start with, mammal and bird population would have exploded very fast back up at any relief in the hyper volcanism catastrophe. And the more they rebounded, the greater the pressure on dinosaurs (This would have happened in addition to other extinction pressures, such as cooling.)
See: https://patriceayme.wordpress.com/2009/11/21/trapped-by-super-traps/
Note 6: A first reading of the ideas above may lead one to wonder why it is that small species do not overwhelm big ones, when they are in competition. But, in normal circumstances, one has an equilibrium ecology, the equivalent of equilibrium thermodynamics. the effect above does not apply. The effect above, exponential extinction, occurs only during non equlibrium ecological dynamics, as found during near-extinction events (hence the importance of near-extinctions). It’s the equivalent of non equilibrium thermodynamics (when Prigogine suggested the latter, he was viewed as nuts; until he got the Nobel Prize). An example of this situation would be a proximal super-nova eruption showering Earth with radiation.
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