Today is Thursday, March 23, 2017

On the Origins of Human Societies: Emerging from the Cradle of Pre-History

By J. Mario L. Guariña III

In an area in what is now the Great Rift Valley in East Africa, a group of small creatures were trudging slowly and uneasily towards a water hole. A nearby volcano had erupted and was spewing volcanic ash for miles around. Eventually, the creatures seeking refuge in the site were buried. Nothing had remained of them except sets of footprints serendipitously preserved in the hardened volcanic ash. Today, some 3.5 million years later, these footprints were unearthed. Examining them closely, anthropologists have come to one of the most remarkable discoveries of our time. The creatures that left the footprints were apes except for one thing - they were walking on two feet. They were bipedal apes.

Fossils of creatures similar to these finds would be found scattered across East Africa. They came to be known by the scientific name Australopithecus afarensis, whose most iconic representative was a partial skeleton called Lucy after a famous Beatles song. Lucy revealed the existence of a creature that with a small brain and large canine teeth looked like an ape, but the foramen magnum or cranial hole of this being through which the spinal cord left the brain and entered the vertebral column was so positioned that, unlike an ape, it could stand up and walk erect.

Bipedalism is now recognized as the first distinctively human characteristic that had emerged from the primate anatomy. Recent finds confirm that there were already apes before Lucy who were walking on two feet. Lucy and her kind had spent their lives as apes did, but because they could walk upright, their hands were freed from locomotion and made available for other tasks. It would take them, in fact, millions of years to realize the potential that was in their hands.


The recourse to tools is not an exclusively human activity. There are reports that, in the wild, apes also use tools. They would strip off the leaves of a twig and use the bare stick to tease out the termites from their earthen mound, or crack nuts by placing them on a flat stone and crushing them with another stone in their hand. What distinguishes men from apes is the extent to which they make and use tools. To apes, toolmaking is, at best, an ad hoc behavior. It is only man who avails of tools in a systematic way, using them as part of his mechanism of adapting to and surviving in his environment.

Evidence for this form of purposeful activity came with a group of creatures that existed some 1.5 million years after Lucy. With somewhat larger brains, they were producing the first known stone tools – lumpish rocks with an edge whacked away to become a hand axe. They had used the tools to cut up the animal carcass for meat. While these implements were rough and crude, more the inventions of marginal scavengers than hunters, they were manifestations of a new phenomenon in evolution. The possessors of these tools were using a cultural strategy in aid of physical survival. They became the first men, homo habilis, men who were toolmakers.

In transforming tool making into a way of life, Homo habilis propelled the development of their brains. With hands that were more humanlike, they became more adept and skilful in the use of tools, and the facility with tools must represent some advance in intelligence. There appeared to be a process of reciprocal interaction between the development of the essentially human hand and the brain, a dynamics that was evident in the arrival of an even larger-brained species, Homo erectus some 1.5 million years ago. With erectus came a more sophisticated stone tool industry – the Acheulean. The stone stools made by these creatures exhibited more regularity and symmetry in design than those of habilis. It was a reasonable inference that erectus had a more advanced way of life. They discovered how to control fire and with better tools must have hunted with more regularity.


But erectus was not the only bipedal primate roaming the plains of Africa. The evolution of erectus was part of the process known as adaptive radiation, in which a novel adaptation, such as bipedalism, leads to the proliferation of many species with that trait, as if nature is experimenting with the forms that can ultimately fit the new niches in the environment created by the adaptation. The anthropologist Richard Leakey classifies the bipedal primates into two basic groups – the small-brain big molar-teeth vis-a-vis the big-brain small molar-teeth species. Erectus belongs to the category of the big brain and small molar teeth as habilis was before it. But at that early stage of primate evolution, having bigger brains did not immediately appear to be a decided advantage.

We can only surmise that when the bipedal apes emerged some five million years ago, they lost out in competition with the ancestors of the gorillas and chimpanzees over control of their original forest cover. They had to leave the trees behind them and strike out for the plains of Africa known as the savanna. Life on the ground was a dicey proposition for them. Except for some crude tools and the protection of their small bands, they were almost helpless in the new environment. They were diminutive in size and lacked the anatomical features that could enable them to compete with the carnivores and other predators on their terms. In particular, they did not have the long, sharp canine teeth of the apes, having given them up in exchange for larger brains.

But some of them did survive, or we would not be here at all. Advance the time line to a million years ago, and we find erectus existing side by side with one or two species of the robust australopithecines, strange-looking creatures with a bony crest on top of their skull, enormous molar teeth and a powerful jaw. They were strictly vegetarians, unlike the hominids who subsisted on a diet of plant foods and meat. With somewhat larger brains than the apes but smaller than erectus, the australopithecines eventually died out, an evolutionary cul de sac. It is hypothesized that they were caught between erectus and the apes and baboons and lost their habitats to them. By a million years before our time, erectus was the only bipedal primate left on the ground.


Despite being the most advanced primate of its time, erectus was not fully human. Nothing better dramatizes the limits of this species than the fact that for the entire length of its existence, which spanned a million years, it continued to make its tools without change or improvement, millennia after millennia. Anthropologists call it a period of unimaginable monotony which is not the way of modern humans.

Erectus’ claim to evolutionary distinction is in having taken the first steps out of the African homeland. Beginning a million years ago and over the next 500,000 years, they had reached as far as Britain to the north and Asia to the east. Their outward trek coincided with the exodus of non-primates like the lions, hyenas and wolves, undoubtedly compelled by the ecological imperative to search for new habitats. The fossil finds during this period included the famous Peking man in China and Java man in Indonesia. They were all Homo erectus.


As we said, erectus eventually went extinct. In the void left behind by their disappearance came creatures with still larger brains and an anatomy that was becoming recognizable as modern. There is a growing consensus to treat them as members of our species, Homo sapiens, or the wise human, but the fossil record is definite that they were anatomically not yet like us. To stress the fact that they were not fully modern, they were called archaic sapiens.

But they were an evolutionary advance from erectus. Give or take several millennia, we can look at 250,000 years as a watershed. This period witnessed the first major technological breakthrough since the million-year Acheulean tradition of erectus, as the hominids were now producing a wider variety of tools and implements never before seen.

A well-known specimen of the archaic sapiens is the Petralona skull discovered in Greece. It was dated to some 300,000 years ago. The brain of this human grew to only a hundred cc smaller than that of the modern, and its face was thrust less forward than erectus but more than the modern. The combination of these features establishes a hominid that was on the threshold of being modern. But not yet. Somewhere and somehow two more developed species emerged. They quickly spread across the vast pristine landscape and competed with each other for its resources. Then some 20,000 years ago, only one remained. The last species standing was the modern Homo sapiens.


The other hominid group was Homo neanderthalensis, more popularly called the Neanderthal man. The Neanderthals were a stockily built people with thick muscled limbs and a brain that was even larger than that of the modern human. They looked very peculiar by our standards. They had a cranium that was long and low and ended with a bun at the back. Their eyes hung below thick ridges and dominated a mid-face that protruded outward. Imagine a face that was made of rubber and pull it out several inches. That would be how a Neanderthal looked. The question is whether such an odd creature could be part of the evolutionary lineage that led to us.

Modern genetic research has given a negative answer. The Neanderthals were never a part of us. Geneticists have found this out by examining the mitochondrial DNA of their fossilized remains and compared it with the DNA of the modern human. The DNA sequencing in both species differed at too many points for the scientists to conclude that the Neanderthals were not our ancestors nor had interbred with them. There is no Neanderthal blood in us.

The genetic evidence combines with the fossil record to underpin the theory that the lineages that led to neanderthalensis and sapiens diverged about 500,000 years ago. We can reconstruct the appearance of the two species from erectus. As we saw, the first hominids were reduced by the harsh realities of what a poet describes as nature red in tooth and claw to only erectus. Thus, the archaic humans who followed erectus in time must have come from the only extant population base which was erectus. There were then two root sources for the Neanderthals – erectus or the archaic humans. So must it be with Homo sapiens. It is almost certain that the modern humans evolved from erectus or some sub-branch of the archaic humans who had their roots in Africa, for that was where sapiens lived until the second exodus some 100,000 years ago. The Neanderthals, on the other hand, were confined to Europe and the Middle East and there, they ultimately came to terms with the moderns who were coming out of Africa.


The evolutionary process that brings about the differentiation of the species is known as speciation. At some stage in the history of a species, a small group acquires a trait by mutation that makes it distinct from the rest of the species. It then buds off from the larger population and, if the new trait confers a survival advantage, the group increases in number. Reproductive isolating mechanisms are then at work that prevent them from breeding with the others that do not share the same genetic innovation. Over time, they become a new species.

The theory suggests that the new species must pass through a bottleneck as it withdraws into genetic isolation. This must have happened to the moderns between 200,000 to 100,000 years ago. If the theory is correct, the population of the moderns from whom we have all descended could be at some point during that time frame not more than 20,000.

It was among this population of several thousand men and women subsisting roughly 150,000 years ago, somewhere in Africa, that a particular woman was born, lived and mated. Without ever knowing it, she occupied the most privileged status in the human saga. She became the genetic Eve, literally the mother of us all. While the lineages of all the other women of her time died out, she left behind a progeny that would eventually spread and populate the world. Beneath our surface differences in race and color, we are all related under one human mother.

The way we have acquired knowledge of this fact is one of the most fascinating leaps of human intuition. It has long been known, for instance, that there is a mechanism embedded in every cell of our body which determines our features or how we look and behave fundamentally. This is known as DNA, a group of molecular structures existing mostly within the nucleus of the cell. There are a few located outside called the mitochondrial DNA, or Mt DNA, which are neutral to natural selection in that the mutations or changes occurring within them do not affect our capacity to survive and reproduce.

Two things about Mt DNA, however, have given scientists the breakthrough in understanding our genetic past. Mt DNA is passed on only along the maternal line or from mother to daughter and the mutations or changes in them takes place at a regular rate over time. It occurred to the scientists that if they would study all the variations in the Mt DNA existing today, they could extrapolate back to a time when the variations would coalesce into a single sequence. They would have arrived at the one person in the past who possessed that sequence and hence, was the source of all the variation – genetic Eve.

In the 1980s, a team of molecular biologists from the University of California in Berkeley started to probe this thesis. They gathered and analyzed samples of Mt DNA from people around the world. The process is known as restriction mapping, and it has resulted in a study that was so astounding that the database was widened to confirm the results. The new studies validated the finding of the Berkeley group.

It is this. Among all the racial groups in the world, the Africans carry the most number of variations in their Mt DNA. All the other races are rooted to a more recent past when their Mt DNA is more or less uniform. Only the Africans differ from them. This can only mean that the African ancestry goes further back in time. Using the rate of mutation, scientists have determined when the Mt DNA of the oldest group coalesced in genetic Eve. The studies prove that she was in existence in Africa some 150,000 years before our time.


Was genetic Eve already a modern human? By genetics alone, we do not know. But there is reason to believe from other evidence that she was. The oldest known human fossil ascertained to be that of a modern was found by Leakey on the shore of the Omo River in Ethiopia. It was dated to about 130,000 years ago. In an evolutionary sense, this human find is contemporaneous with Eve. To say that Eve was still erectus or archaic sapiens both of which were species past their time seems out of the question. It is a safe bet that Eve was a modern Homo sapiens.

The second human exodus, to be pursued by the descendants of Eve, would start by 100,000 years ago. Some caves in Israel bear signs of occupation of moderns who must have walked north of the Red Sea and across the Sinai Peninsula. Much later, by 60,000 years, to the south at the Horn of Africa, the migration became waterborne. The moderns crossed over to the Arabian Peninsula and, rounding the Persian Gulf, moved to India, Southeast Asia and finally, Australia. The journey took them many millennia to accomplish, but it was not as if they knew where they were going. They must have established settlements along the coastal regions, and one generation after another kept pushing into still unknown regions. They left no archaeological evidence of their presence along the way, but the genetic evidence is clear that they were there. Common to the present-day people in the area is a mutation in the Mt DNA that was traced to a woman living in East Africa more than 60,000 years ago. The people who later migrated to Asia through the Horn of Africa carried this distinctive genetic marker.

From Central Asia, the moderns continued to spread, reaching north to Beijing China and braving the frozen land bridges of the Arctic to reach America. Another line veered to the west and headed for the Middle East and Europe. Around 45,000 years, sapiens and neanderthalensis met again, an encounter that would put to an end the Neanderthal line in Europe. The group of moderns who were fated to bring this about was the Cro-Magnon.


The demise of the Neanderthal man with the advent of Cro-Magnon is the greatest mystery occurring in the story of our remote past. For 25,000 years later, his species had disappeared completely. How did this happen? There is a theory that the replacement was anything but peaceful. It is, indeed, tempting to imagine a race of humans equipped with better tools and weapons and, meeting an inferior people, systematically wiped them out. The phenomenon is not unusual in human history. It was only a few centuries ago when the native populations of the Americas were almost eradicated through violent confrontation with the Europeans. There is, however, no evidence of wholesale carnage in the skeletal remains of the Neanderthals. A more prosaic explanation is needed.

We believe that the extinction of the Neanderthal was a slow inexorable process resulting from his inability to compete with the Cro-Magnon in a deteriorating environment. By 20,000 years, the ice age was reaching a glacial maximum. Only scattered areas along the southern edges of Europe were available for human habitation, while all around them was a vast frozen wasteland. Under these conditions, Cro-Magnon appropriated most of the existing resources in order to survive, forcing the Neanderthals to even less hospitable areas. Demographic studies have shown that a small but persistent drop in the birth rate below the death rate can cause a population of millions to be extinct in a thousand years. We surmise that this was the fate of the Neanderthals. Less than 20,000 years ago, the last Neanderthals went to their graves in some desolate cave in Southwestern Europe.


If there is one thing that the disappearance of the Neanderthal ought to tell us, it is that the Cro-Magnon was a more advanced people. This statement sounds almost tautological, but we say it nonetheless to bring our attention to the ultimate goal of our inquiry – the cause or reason for the evolutionary success of Homo sapiens. The mental level of the Neanderthal could not have been significantly different from the Cro-Magnon. They had the same large brains and a similar capacity for language. Like Cro-Magnon, the Neanderthals lived in family and kinship groups and used tools. They led a revolution in stone technology called the Mousterian which improved on the tools of erectus, by using the stone core to yield flakes of different varieties instead of merely chipping at the outer edges of the stone as erectus did. They progressed to a degree that they were beginning to manage their environment. It is estimated that by the time of the arrival of the moderns, they numbered about a million across Europe.

If the superiority of the moderns over the Neanderthals was not lodged in the genes, there can be only one explanation left. The difference between them was social or cultural, the result of a change in the way they lived, behaved and interacted among one another. Some studies have zeroed in on an underlying factor – a social phenomenon we may call intergroup cooperation and alliance.

Verily, hominids, like their primate cousins, are social creatures. But until modern humans came to the scene, the sociality of primates consists basically of nuclear units engaged in the breeding of offspring. These units are greatly constrained by the bonding process and dominant behavior among its members. Only in the most superficial of ways do the primates develop social relations with others not belonging to their immediate breeding group, whether it is to forage together to collect more food or sleep in a common nesting place for mutual protection. On the whole, primate groups are aggressively hostile or, at the very least, indifferent to one another. We can theorize that as hominids emerged from their primate past, they brought with them essentially the same baggage of collective distrust and xenophobia.

Modern humans, however, did something no other hominid or primate before them had done. They reached out to one another, despite the fact that they lived in separate groups, in ways that resulted in the expansion of social relationships beyond the elemental social units. Human society was born – midwifed, as the sociobiologist Edward Wilson points out, by a system of reciprocation among distantly related or unrelated individuals. The process was hastened exponentially by the use of language, which enabled them to understand one another in increasingly complex situations.

The efflorescence of cultural activity associated with greater mobility of the moderns came during the last phase of the Stone Age before the discovery of the metals called the Upper Paleolithic in Europe. Many archaeological sites in that continent dating from 45 thousand years ago to the close of the last ice age 12 thousand years ago yielded improved blade tools made of raw materials that had to be brought across large distances. In only a few thousand years, tools and weapons from Eastern Europe had spread throughout the continent picking up regional styles and distinctions along the way. Other cultural inventions proliferated – beads, ornaments, and figurines. Tools of bone and antler were also made and decorated, and weapons that could be hurled, like harpoons, spears and the bow and arrow finally made possible the hunting of big game. The cultural way of life was developing an engine of its own that no longer depended on organic evolution.


By the end of the last ice age, the moderns were living in clans or tribes - alliances of groups bound by kinship and other personal ties. But they were still hunters and gatherers as hominids had been since the time they invented tools two million years ago. They had already domesticated some animals but, by and large, they kept following the migrating wild herds as the seasons rolled. They were a nomadic people and, as Jacob Bronowski wrote, the civilization of a nomad is limited to the things he could carry on his back.

Then, some ten thousand years ago, the single most important discovery took place since the advent of controlled fire. Men found that plants like wheat, which are a source of food and nourishment, could be planted and grown. The event had to occur in the Middle East where the soil was rich and fertile from the annual overflowing of the Nile River. The agricultural revolution began. In time, fixed settlements like Jericho were rising in the region, which were to be the centers of future city-states and empires. As more and more people came together on a permanent basis, social interactions grew more varied and complex, and ideas and inventions multiplied. The most momentous advance was the invention of writing some six thousand years ago. It ushered in the age of written history.

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