Why one branch on the human family tree replaced all the others

The cave of Es-Skhul is located in Israel on the western slope of Mount Carmel. This is where nomadic hunter-gatherers set up camp during the Ice Age, some 140,000 years ago. As the sea moved to the west, a wide plain with meadows full of anemone and asphodel and groves of live oak, almond, and olive trees was revealed. Rhinos, aurochs, and herds of fallow deer roamed the plains. They used stone-tipped spears to hunt animals and collected olives and mustard from the wild. And they buried their dead near the cave’s entrance after they passed away. Some of the earliest members of our species, Homo sapiens, are represented by the skeletons discovered here. However, we were not like these Homo sapiens.

The thick skulls, enormous jaws, and brow ridges that were characteristic of Neanderthals and other primitive humans were still present in their skulls. However, they weren’t our ancestors despite their archaic appearance; they came into the world too late. They are a side branch of our evolutionary tree that vanished without producing any offspring. Why did we live while they perished?

Their skulls might hold the solution. They lacked the unusual anatomical characteristics of juveniles of other hominins and apes, such as small brow ridges, bubble-shaped skulls, reduced jaws, and thin cranial bones, which are shared by modern humans. When compared to other hominins, we are essentially infantile. We probably became more gregarious as a result of selection favoring juvenile traits like low aggression and an openness to new experiences and people, which also led to the development of our immature-looking skulls. Paradoxically, it’s possible that modern humans’ sociability and lack of aggression were what made them so dangerous to these early Homo sapiens.

After the initial excavation of Skhul Cave in 1929, pieces of ten skeletons were eventually discovered. Soon after, at least 28 people’s 90,000-year-old remains were found at the nearby Qafzeh Cave close to Nazareth. The remains of the Skhul and Qafzeh were among the earliest known human remains when they were discovered. A century later, they remain the same, and there is ongoing discussion about what they mean.

These people are very much like us. They resembled us more than Neanderthals, who had long braincases and sloping foreheads, with their high foreheads and domed heads. Their brains were about the same size as ours. Unlike Neanderthals and other species, their jawbones had strong chins. The Skhul and Qafzeh fossils are remarkably archaic in other respects, however.

Like Neanderthals and Homo erectus, they have enormous brow ridges and extraordinarily thick skull bones. They had enormous molars in their broad, massive jaws. Although we are unsure of their exact appearance, they most likely didn’t resemble anyone you would see on the street today.

In order to string seashells on cords for necklaces, they punched holes in them at Qafzeh.

This blend of advanced and primitive is also evident in artifacts discovered with the Skhul and Qafzeh fossils. Their implements were a part of the Mousterian tool tradition. Though more archaic than the tools created by contemporary Homo sapiens, Mousterian technology was more sophisticated than the rudimentary Acheulian tools, such as the handaxes used by early Neanderthals. Smaller stone instruments, such as striking flakes and blades of disc-shaped stone cores, had replaced Acheulian hand-axes among the Skhul and Qafzeh people. They produced Mousterian points, which are large, triangular spearpoints. They accomplished this by using a flintknapping method known as the Levallois technique, in which a big blade was struck off in a single motion after a stone core was prepared. Throwing spears to hunt large game, and most likely other people, was associated with Levallois points. Oddly, the last Neanderthals are also linked to Mousterian tools. Did Neanderthals acquire their technology from contemporary humans, or did modern humans acquire their tools from Neanderthals?

The Skhul and Qafzeh people’s artifacts and behaviors were, in some respects, surprisingly sophisticated and human. They made holes in seashells at Qafzeh so that they could be strung on cords to make necklaces. It would have been roughly thirty miles to the sea at that time. They may have traveled that far as a result of their wanderings, but it’s also possible that they traded for shells, which is not a behavior associated with Neanderthals. It was also discovered that some skeletons were covered in ochre pigment, which is commonly used for painting, cosmetics, and décor. [].

It is noteworthy that a number of skeletons were discovered interred with grave goods, which is not a custom known to Neanderthals. On the chest of a man buried at Skhul was a boar’s jaw. At Qafzeh, an adolescent boy was interred curled up with an elk’s antlers. It is unknown what this practice meant; these artifacts might have been offerings, charms, or trophies. Perhaps they helped or shielded the deceased’s spirits. Furthermore, the burials themselves allude to a hereafter, and the fact that so many bodies were discovered in such a small area implies that these locations held some spiritual significance for them. Perhaps the deceased were brought to the caves by loved ones to join the spirits of their forebears.

There is still no universal agreement among archaeologists who have been trying to interpret the Skhul and Qafzeh bones for a century. It has even been controversial to assign skeletons to a species. The skeletons were initially assigned a species of their own, but later on, they were thought to be Neanderthal-human hybrids or a transitional species between Neanderthals and modern humans. It is currently believed that they belong to the Homo sapiens species, which is more closely related to us than to Neanderthals. But how do they relate to us, if at all?

Although the term “anatomically modern” is being used extensively, the Skhul and Qafzeh remains are frequently referred to as anatomically modern Homo sapiens. The emphasis that archaeologists choose to place on the glass is somewhat arbitrary; is it half-modern or half-archaic? If you’re curious about the origins of modern humans, you might want to highlight the modern features of their skeleton, but I find the primitive features more fascinating. The phrase “archaic Homo sapiens” appeals to me. This recognizes their connection to contemporary humans as well as their separation from living people. Or perhaps we should simply refer to them as the Other Sapiens.

Ancient Homo sapiens have been found in other parts of the Middle East and Africa since the discovery of Skhul. Additional information has revealed the mystery, as is common in science. Archaic humans have recently been discovered in Florisbad, South Africa. They can be found in Ethiopia’s Herto and Omo Kibish localities, Tanzania’s shores around Lake Eyasi, and East Africa. Archaic humans have been discovered in Iwo Ileru Cave in Nigeria, as well as in Jebel Irhoud and Dar Es Soltan in Morocco.

The most successful, numerous, and widely distributed humans of the archaic era were archaic sapiens.

Remarkably, some have even been discovered in Europe. An ancient human skull was discovered in Greece’s Apidima Cave, and teeth were discovered in France’s Grotte Mandrin Cave. Tens of thousands of years before modern humans left Africa, they reportedly participated in the first human migration out of the continent.

Not only were archaic humans widespread, but they were also the most prosperous and successful people in their era. Archaic humans would have outnumbered Neanderthals, who were confined to the harsher climates of Ice Age Europe and Asia, because they lived in most of Africa, where they had easy access to game and plants for food. In contrast, it is believed that modern humans lived in a small region of southern Africa, where there were no more than 30,000 people.

Additionally, archaic humans lived a long time. The oldest known human remains are from Morocco, and they date back 315,000 years. These are the earliest humans outside of Africa, with a jaw from Misliya in Israel dating back 177,000 years and a skull from Apidema in Greece dating back 200,000 years. They had been in existence for a while. They did, however, live until quite recently. They dominated the Homo sapiens kingdom until roughly 50,000 years ago. A jaw or tooth that doesn’t have ancient characteristics like theirs is hard to find before that.

This all begs the question. How exactly do these early Homo sapiens fit into our evolutionary tree? Were they our ancestors, or more likely, rival branches?

In terms of their actions and thoughts, how contemporary—how human, if you will—were they?

Finally, where did they disappear to? Did they become assimilated into contemporary populations, evolve into them, or just vanish?

And why are we still living today if they did go extinct?

Seeing archaic humans as our direct ancestors is alluring because it would answer a significant question regarding our origins. Since Skhul people and other archaic sapiens are transitional forms—”missing links” between more primitive, Neanderthal-like hominins and fully modern humans—they exhibit an odd blend of primitive and modern traits. The explanation is straightforward and apparent, but as is frequently the case, it appears to be incorrect. The fossil record simply shows archaic humans too late to be our ancestors.

We have yet to find the remains of the earliest modern humans.

It is still unknown when modern humans first appeared. The fossil record for hominins is incredibly lacking. A small number of teeth from Tanzania’s Mumba Rock Shelter, which is located on the shores of Lake Eyasi, are the earliest fossils of fully modern humans. They are indistinguishable from modern-day Africans due to their lack of archaic features and approximately 100,000-year age.

According to human genomes, modern humans might have evolved considerably earlier, and the remains of the earliest modern humans have not yet been found. Scientists frequently use DNA divergence dating, which compares genetic differences between populations to determine how long ago they split, to estimate when our species emerged. The idea behind these molecular clock methods is that mutations build up over time. Two populations’ DNA differs more the longer they have been apart.

Theoretically, we could determine when two lineages split apart if we could estimate how quickly DNA evolves. Although it’s not a precise science—almost a dark art—molecular clocks have a significant advantage over fossils in that they can look back in time, even in places where the fossil record is absent. Moreover, the majority of the record on human evolution is absent.

Our direct ancestors lived between 250,000 and 350,000 years ago, according to a molecular clock model applied to modern humans. This population most likely resided in southern Africa, which has the highest genetic diversity of humans and frustratingly few fossils, between the Congo and the Okavango.

These early modern humans most likely resembled us in appearance. The San, Pygmies, Hadzabe, Bantu, and the diaspora that gave rise to Eurasian and Amerindian peoples all have thin skulls, delicate jaws, and small brow ridges, so it is likely that they did as well. They probably looked like contemporary African hunter-gatherers—short, wiry, with black, curly hair and copper or brown skin.

People who are archaic simply never stop being archaic. After that, they vanish and we show up.

This suggests that before primitive-looking people like Skhul and Qafzeh appeared in the Levant, essentially modern humans had already evolved tens of thousands of years earlier. Archaic humans cannot be our ancestors if that is the case because the dates are incorrect. People from the Skhul and Qafzeh cultures lived between 80,000 and 120,000 years ago. The Omo Kibish 1 skull was created about 230,000 years ago, and the Herto remains were created about 160,000 years ago. Stone tools indicate that the last archaic people in North Africa vanished some 20,000 years ago, while remains from Grotte Mandrin in France date to approximately 54,000 years ago. In conclusion, prehistoric humans in Iwo Ileru, Nigeria, lived until approximately 12,000–16,000 years ago, just prior to the conclusion of the last Ice Age. Long after modern humans had colonized Australia, expanded into Europe and Asia, and crossed the Bering Land Bridge into Alaska, the archaics continued to exist until very recently.

Around the same time that our ancestors would have lived, a few archaic humans appeared. The skulls from Florisbad, South Africa, and Jebel Irhoud, Morocco, both date to 330,000 and 250,000 years ago, respectively. However, they should either be much older than contemporary humans or have far more modern anatomy if they were genuinely ancestral. The timing thus implies that our ancestors are not archaic. Rather, they are our relatives.

Fossils do not demonstrate an evolutionary trend toward modernity, which is another issue with the archaics as ancestors theory. Smaller jaws and brow ridges would be seen in younger populations of Skhul and Qafzeh people if these ancient sapiens developed into modern humans. They don’t, though. To the end, archaics simply remain archaic. After that, they vanish and we emerge. This discontinuity points to replacement rather than evolution. Similarly, the evolution of stone tools is sudden rather than gradual, as we might anticipate if they gradually evolved into modern humans.

No more than Neanderthals, Skhuls and other archaic peoples were on the evolutionary main line. Among these competing lineages, we defeated the Neanderthals, Denisovans, and Homo erectus. Some time after humans split from Neanderthals, approximately 750,000 years ago, but before modern humans evolved, approximately 300,000 years ago, these ancient side branches must have broken off from the main line of humans.

It is possible that archaic peoples are a subspecies of modern humans, but how do these archaic lineages relate to modern humans? It is more probable that they represented several subspecies due to their extensive geographic range and anatomical diversity. There are distinct groups of modern humans in different parts of the world. For example, the Pygmies in Central Africa broke away from the rest of humanity about 200,000 years ago, and the San in southern Africa have been evolving essentially alone for 300,000 years. Likewise, over hundreds of thousands of years, early Homo sapiens likely witnessed lineages split off and migrate into various regions of Africa, the Middle East, and Europe. It’s likely that some lineages were more similar to modern humans than others. Their braincase is elongated, almost Neanderthal, making the Moroccan Jebel Irhoud sapiens appear even more primitive than the others. This person is an ancient human. Perhaps closer to us, the Skhul and Qafzeh hominins have some of the most advanced anatomy.

However, it is obvious from looking backwards what we refer to as the “main line” and what constitutes a “side-branch,” so what does it even mean to call them “side-branches”? Since we are present and they are not, we can refer to ourselves as the main line. The history and anthropology textbooks are written by winners. However, at the time, neither they nor we were clearly the main line or branches. Out of numerous rival sapiens lineages, modern Homo sapiens was one unsuccessful side branch, with a total population of maybe 30,000 individuals. Could an alien exobiologist who had traveled to Earth to study humans have foreseen that our bubble-headed subspecies would eventually supplant all others?

In any case, we know that the brains of archaic humans were large, within the range of variation observed in modern humans, but slightly smaller than average. They were also anatomically similar to us, so it makes sense that their behavior would have been similar to ours. They most likely shared traits with all human cultures, such as sophisticated tribal structures and languages. They might have held beliefs in magic, ghosts, and gods. Though not wholly unsupported by evidence, these conclusions are speculative. The fact that ancient humans interred their dead suggests a belief in the paranormal. The Hadzabe hunter-gatherers of Tanzania bury their dead in rock shelters to join their ancestor spirits; perhaps the residents of Skhul and Qafzeh did the same, believing in ghosts and ancestors. Furthermore, the high level of complexity of some modern human traits—such as language, dance, song, music, and spirituality—indicates that these traits existed long before we evolved. It’s highly unlikely that language, in particular, developed during the few hundred thousand years of evolution that separated us from other humans because it is such a complex adaptation. Rather, it most likely developed gradually, much like the skeleton of today. Therefore, it is logical to assume that they spoke some kind of language.

The kind of sophisticated technology that modern humans have created was never created by ancient humans.

Like contemporary humans, we also observe the Skhul and Qafzeh people using a lot of shell beads and red ochre pigments; they might have shared our sense of beauty and vanity. One notable characteristic of the archaic people is that, unlike Neanderthals, they sourced materials over great distances. Even though Qafzeh Cave is about thirty miles from the ocean, these people managed to get marine snails to make shell beads. Resources can be obtained over such vast distances in two ways. One option is to stroll through an area that is friendly. As demonstrated by the Sand and Hadzabe hunter-gatherers, where a tribe of 1,000 can rule over an area of more than 4,000 square kilometers (1,500 sq miles), this suggests a comparatively large area governed by a single, sizable tribe. Another option is to engage in trade with nearby tribes. Large, widely dispersed social networks are implied by both scenarios.

The sophisticated behaviors we don’t observe, however, are equally remarkable. Modern humans have developed sophisticated technology that was never created by archaic humans. Their spear throwers and bows were absent. They didn’t paint horses in caves or carve ivory figurines of Venus. They don’t exhibit quick technological advancement either. The Skhul and Qafzeh appear to have utilized the same implements as the Neanderthals for a period of 100,000 years. The spread of modern humans throughout Eurasia some 50,000 years ago is when technological innovation really takes off.

The fact that the archaics had difficulty repelling the Neanderthals is another noteworthy aspect of them. After taking root in the Middle East, the archaics eventually made their way to western Europe. However, this attempt to enter Neanderthal territory was ultimately unsuccessful. They were supplanted by Neanderthals 150,000 years ago in Greece, 70,000 years ago in Israel, and 55,000 years ago in France. That is significantly different from the pattern observed in contemporary humans.

About 50,000 years ago, modern humans began to rapidly expand into the Middle East, Europe, and Asia after first migrating from Africa into the Arabian Peninsula. By 35,000 years ago, all Neanderthals had been wiped out. Neanderthals were never able to advance and regain lost territory against contemporary humans. Neanderthals were inferior to modern humans. We don’t know what that edge was, but it seems to have been absent from the archaics.

Our evolutionary advantage over the Neanderthals must have been greater than that of the ancient Homo sapiens, for whatever reason.

The disappearance of the archaics, then, was probably due to the same cause as the disappearance of Neanderthals, Denisovans, Homo erectus, Homo rhodesiensis, and all other primitive human lineages. They were replaced by modern humans. We either drove them out and seized their land, or we killed them outright. They dwindled in number as they had less and less land to hunt and gather for food. They eventually vanished completely.

This pattern appears repeatedly throughout human history: violence or the threat of violence is nearly always used to replace one human population with another. Native American lands were forcibly taken by American settlers and the military. Tribes of Native Americans had previously engaged in conflict and seized territory from other Indigenous groups. Aboriginal peoples in Australia and Māori in New Zealand had their lands taken by force by the British. The Khoikhoi herders and Bantu farmers in South Africa seized the San people’s ancestral lands.

This occurred gradually. . Research on the genetic diversity of humans indicates that there were only 25,000 to 30,000 modern humans at first. An area the size of England or Iowa could have easily contained the entire population, assuming population densities similar to those of African hunter-gatherers. In the meantime, archaic humans lived in the rest of Africa, including Ethiopia, Tanzania, South Africa, Kenya, and parts of the Middle East and Europe. However, contemporary people gradually dispersed.

We became more numerous as we spread across sub-Saharan Africa. In South Africa and East Africa, we supplanted prehistoric Homo sapiens. Then we left Africa. Homo erectus was exterminated when we first entered Southeast Asia via a coastal route. About 50,000 years ago, modern humans began to rapidly spread, possibly as a result of the invention of the bow and arrow. They quickly displaced Neanderthals in Europe and the Middle East as well as the Denisovans in East Asia. Around 24,000 years ago, we finally moved into North Africa, where we drove out the prehistoric humans. About 13,000 years ago, the last known archaic humans vanished from West Africa. The archaic people lived a very long time after Neanderthals and Denisovans. even after the arrival of modern humans in Europe, Australia, and the New World.

Since modern humans supplanted all previous human lineages, the extinction of archaic humans was a part of a larger wave of extinction. We are the only hominin species still alive, out of maybe ten that existed when we first appeared. However, our own species used to be much more varied; modern-day humans are only one branch of a much larger branch.

It is possible that the extinction of archaic humans was not complete. Given that humans appear to have a penchant for interspecies mating, it is plausible that contemporary humans intermarried with these individuals, just as we did with Neanderthals, Denisovans, and possibly Homo rhodesiensis. If this is the case, some ancient DNA may still exist in contemporary human populations. There are indications of hybridization in at least some skulls. One of the earliest modern humans in North Africa is a 33,000-year-old Homo sapiens skeleton from Nazlet Khater, Egypt. Even though the majority of the remains are modern, the jaws still have some primitive characteristics, suggesting that the Nazlet Khater skeleton is a hybrid. Thus, ancient genes might have gotten into contemporary populations in North Africa, and possibly other places as well. This kind of interbreeding may be difficult to identify because, in terms of skeletal anatomy or DNA, interbreeding humans with other humans would be much less evident than interbreeding with Neanderthals.

In our constant struggle against other hominins, modern humans have never given up.

Perhaps archaic DNA got into our genes in a more indirect manner. Neanderthals provided modern non-Africans with roughly 1-2 percent of their DNA. Interestingly, however, research on Neanderthal genomes indicates that approximately 6% of their DNA was passed down from modern humans during a hybridization event that occurred some 250,000 years ago. Archaic Homo sapiens may have been the origin, as that was a long time before modern humans left Africa and around the same time that they arrived in the Levant. If this is the case, statistically speaking, it is probable that some of the genes that modern humans inherited from Neanderthals may have originated from archaic sapiens, in a genetic back-and-forth.

Approximately 0.1 percent of non-African populations’ DNA may have originated from archaic humans in this manner, according to a haphazard calculation. Although it may seem insignificant, it represents approximately 3 million base pairs out of the 3 point 2 billion base pairs that comprise the human genome. Furthermore, any genes that survived in Neanderthals and then in humans were probably maintained by natural selection; it’s likely that they’re benefiting our physiology, brains, or bodies.

Was it simply bad luck or was our survival and their extinction inevitable?

It is evident from the archaeological record that modern humans have consistently outperformed other hominins and have never relinquished the advantage. Unlike Neanderthals and Denisovans, modern humans always drove out ancient sapiens wherever we went. Although they kept us at bay for a while—sometimes for millennia—other people were never able to retake the territory they had lost. Luck must have played a significant role in the rise of Greek civilization against Persian civilization, for example, as the rise and fall of civilizations in civilized history frequently depended on a few major battles.

Nevertheless, the success of modern humans must be the consequence of innumerable thousands of battles, as prehistoric wars were fought over millennia through attrition and small-scale raids and ambushes. We consistently prevailed more often than we lost. Our success wasn’t a coincidence; rather, we were superior to other people, not just fortunate. What was the advantage that modern humans had?

It’s possible that we were more adept at using technology and tools. Bows, spearthrowers, and stone-headed axes are examples of weapons that modern humans invented; Neanderthals and archaic humans did not create them or even use our technologies. Furthermore, technological superiority extended beyond armaments. During the middle of the Ice Age, some 40,000 years ago, modern humans moved into Siberia’s high arctic, something Neanderthals never did. That’s strong evidence that we mastered innovations like cold-weather clothing, shoes, and the needles and thread needed to sew them. Modern humans colonised Australia by boat around 65,000 years ago; no other lineage crossed long distances over water.

Another possibility is that we were better with language. Language wasn’t unique to modern humans; Neanderthals probably had a form of speech. The hyoid bone that supports the soft tissues of the throat is highly modern in Neanderthals; they also had modern ear anatomy, suggesting they could hear the sounds of language. But it’s possible we were more refined linguistically, better able to communicate with one another to socialise, and also to wage wars, compared with other humans.

There may have been other, less obvious benefits for us. The ability of contemporary humans to form sizable social groups is among our most remarkable characteristics. African hunter-gatherers usually live in groups of a few dozen, which can combine to form tribes of hundreds or even a thousand members. The low genetic diversity found in Neanderthal DNA research, on the other hand, points to greater inbreeding because they belonged to more secluded, smaller social groups. We must have had more intelligence to solve problems and come up with tool-making methods because of our large social groups. However, the ability of large tribes to take or defend land may be more significant. If archaic Homo sapiens resembled Neanderthals in having small social groups, this must have put them at a disadvantage against modern humans.

Rebuilding social structures for people who lived tens of thousands of years ago is obviously challenging. Still, could the anatomical differences between us and the archaics tell us something – could a clue to our superiority lie in modern humans’ weird skull shapes, where juvenile features are retained into adulthood?

A similar pattern is seen in domestic dogs – dog skulls are shaped like those of wolf puppies, and they have thinner skull bones too. The process of domesticating dogs for lower aggression produced something that looks like a young wolf. This may be a side-effect of selecting dogs for characters found in wolf puppies – less aggression, more playfulness, more friendliness.

So it’s possible that a sort of process of domestication gave modern Homo sapiens our weird, immature skulls, including big, domed heads, loss of brow ridges, small jaws, and thin skull bones. If the bones look immature, maybe the brain inside was too. Perhaps youthful creativity, imagination, faculty for languages, playfulness, why’s-the-sky-blue curiosity, willingness to make new friends were all retained late in life in us, compared with other humans – with selection for child-like behaviours creating our child-like faces.

The expansion of modern humans was a long, gruelling war of attrition, not a blitzkrieg.

Paradoxically, low aggression may have been a massive advantage in intertribal warfare. Low aggression could have helped us to form big social groups – tribes of hundreds and thousands. And modern humans don’t just form huge groups, we’re unique among animals in being able to form peace treaties between different groups, and alliances between groups to defend or attack territory. What made modern Homo sapiens so uniquely dangerous might not have been a tendency towards violence and aggression, but friendliness, and the ability to forge alliances. The ability to create groups and social networks, and hold off fighting – at least, until we’re in a position to win – could have given us a decisive edge.

I’m the only one who survived to tell you.

Within Homo sapiens, we see this pattern repeated, with lineages others than our own stripped away, a diversity of peoples whittled down until only one remains. We were just one of many different lineages, but now we’re alone. All that remains of the others are stone tools, a few skeletons, perhaps a few of their genes mixed with ours.

We don’t know how this replacement played out. In some cases, the large size of modern human social groups probably allowed our ancestors to move in and seize territory without a fight, forcing archaic humans onto more marginal land. But in many cases, the conflict between modern humans and archaic sapiens was likely violent. The remarkably slow spread of modern humans – it took perhaps 300,000 years for us to completely displace archaic sapiens in Africa – implies that archaic humans resisted fiercely and effectively. It took hundreds of thousands of years of intertribal warfare for modern humans to spread from our homeland in southern Africa to the far edges of the continent. Even the final, rapid push from Egypt to the northwest tip of Africa took more than 10,000 years – just half a mile per year. The expansion of modern humans was a long, gruelling war of attrition, not a blitzkrieg. This also tells us something about just how human they were – the edge we had was decisive, but not overwhelming – they must have been very like us to fight us off for so long.

The evolution of the human species, much like art, would have been both an additive and a subtractive process. Shakespeare put words on the page, then deleted lines and whole scenes. Evolution is the same. It adds new genes to a population through mutation. It subtracts genes by eliminating individuals, populations, entire species. When Michelangelo sculpted the statue of David, he chiselled away every piece of stone that didn’t look like the ideal human form. In the same way, evolution worked on the raw material of Homo sapiens, carving away everything that wasn’t a modern human. To be more precise, we ourselves did the carving, slowly stripping away other species and other lineages, until modern humans remained.

This process didn’t begin with us. Over millions of years, increasingly advanced hominin species appeared, with bigger brains and more advanced tools and language. They tended to displace the more primitive species. The acquisition of spear-throwing and hunting by Homo erectus probably saw the primitive Australopithecus species killed off – even hunted and eaten – by their advanced rivals. And in the Levant, we see a series of species move through, as new and more advanced hominins evolved in Africa and then migrated out – the ancestors of Homo erectus, Homo antecessor, Neanderthals, archaic humans and, finally, modern humans, each wave replacing the one that came before.

This process did, however, end with us. After thousands and millions of years, one lineage emerged to replace all the others. This probably explains something about our history, and our tendency towards war and conflict. We may live in civilisation today, but the genes within us are those that made us the sole survivors of hundreds of thousands of years of intertribal conflicts and bloody, genocidal wars. We replaced all the other humans because we were more dangerous than all the others. Today, all human diversity derives from a small population that lived a few hundred thousand years ago. The picture was very different when we first evolved. Then, there were 10 or more different human species. All of them have since disappeared.