From Section 3: Integration to Conversion

One way to step back from the uncertainties of the human evolutionary story is to consider events from a broader perspective, such as a timescale that is more in line with those paleontologists have used to track other lineages through the geological record - say one with million year intervals. If we take a fossil-based snapshot from around four million years ago we find a hominoid scene dominated by an assortment of bipedal apes living in eastern and south-eastern Africa, and with minor changes in a few of the apes we get a similar picture from three million years ago. By two million years ago the fossils tell us that some of the smaller hominoids have declined throughout much of the ancestral heartland, which is now dominated by the brainier and more carnivorous hominines, primarily habilines and erectines. The snapshot from one million years ago shows a different scene again, with robust, large-brained erectines dominating the scene from Africa to the islands of south-east Asia, although in some areas of the hominine world they are giving way to even larger-brained archaic humans, some of whom are also heading north into Europe and central Asia. Somewhat surprizingly neither of these forms feature in the snapshot from around twenty thousand years ago, which shows populations of people like us scattered across most of the land that is not covered in ice, where their small and often nomadic groups inhabit an unprecedented range of environments, landscapes and living communities.

This timescale shows us that the geologically sudden rise to prominence of modern humans fits with the recent history of our lineage, which is itself consistent with what we know about what was going on in the living world at the time, and with what has been going on since time immemorial. For instance it appears that the ancient hominine world and the modern human one were both founded by regional populations whose competitive and adaptive advantages allowed them to rapidly expand and extend their ranges while absorbing or supplanting other populations, and such "rapid replacement" events have been linked to one of the commonest patterns of evolutionary change observed in the entire fossil record: punctuated equilibrium. This pattern is easy to pick out in lineages of abundant, easily-fossilized creatures whose populations had the luxury of remaining largely unchanged for tens of millions of years, but such a leisurely evolutionary pace is not typical of the current geological period, nor of mammals, nor of creatures that have faced the kinds of challenges our hominoid and hominine ancestors did. They lived in a world where living communities, landscapes and climates were subject to some of the most frequent, rapid and extreme fluctuations in the history of the living Earth, which were no doubt often attended by equally dramatic population depletions, expansions, migrations, displacements and replacements. Hence the fossil record for the past few million years shows patterns of rapid and dramatic change unfolding in many lineages besides our own, including those of several of the animals our ancestors would have been familiar with, such as dogs, horses, cats and elephants.

So when we step back and look at the overall picture, the earliest people like us take their place as the latest in a long succession of successful representatives of a lineage whose development, like that of many others, was strongly influenced by an era of dramatic challenges and opportunities. Like many of those who survived and thrived alongside them our early ancestors owed most of their success to adaptation, and it is their approach to meeting challenges and exploiting opportunities which made them unique among humans and among living creatures in general. The pioneering groups of modern humans who travelled so far so quickly and moved into so many different natural situations were the first complex organisms we know of whose adaptive and competitive skills arose from powerful and flexible intellects that allowed them to rapidly and radically alter their lifestyle habits, technologies and other aspects of behaviour to fit a wide range of circumstances. I referred to this earlier as active adaptation, and another way of describing what made the first people like us both unique and successful is that they discovered how to learn to adapt.

This is not to say that our ancestors were liberated from the rules that apply to all other organisms, or that they stopped evolving in the more traditional Darwinian fashion. As they moved farther, faster and into a greater variety of situations than any of their predecessors they rapidly gave rise to an assortment of regional populations, which as they passed through hereditary bottlenecks and became reproductively isolated from each other in different environments naturally began to accumulate genomic and physical differences, like those that distinguish present-day equatorial African Masai from arctic American Innu. Such divergences are superficial, however, when compared to what went on in the cultural realm, where even people who shared common ancestries often ended up living and acting quite differently from each other. As with genomes, some cultural differences arose from chance divergences, like the variations among spoken languages, while others were related to adaptation, such as lifestyle differences that emerged among people living in different environments and living communities. And some aspects of cultural change are a bit more difficult to classify, such as the malignant tendencies we have been trying to track down. This brings us to a question that may seem a bit premature, since in the preceding chapter we associated macromalignancy with those relatively recent inventions, ecosystems and large societies. Yet we have also seen that the progression of social and ecological malignancies is associated with rapid population growth, innovation and cultural evolution, all of which featured in the rise of modern humankind. Thus it is reasonable to ask: did people like us have malignant tendencies before they became settled or civilized?

In order address this question from a paleoecological perspective we would need some way of assessing the actual impacts our early ancestors had upon their surroundings, which is difficult considering the evidence is so thin on the ground and open to interpretation. Indeed it is possible for people to have significant impacts upon their surroundings without leaving obvious signs behind. For example hunters and pastoralists the world round preserve open grazing land for their favourite animals via the simple, effective and ancient (it may have originated with Homo erectus) practice of deliberately setting brushfires that are archaeologically indistinguishable from spontaneous fires. In cases where the ancient evidence can tell us of ecological impacts, definitive conclusions are still elusive. For instance some researchers have noted correlations between the arrival of modern humans in certain areas and the decline in populations of animals they were known to consume and/or compete with, such as mammoths and cave bears. These observations implicate our early ancestors in the decimation and possibly even extinction of animal populations, but a conviction is far from certain given the other suspects that could have been involved. For example some mammoths appear to have been in difficulty due to climate changes long before prehistoric hunters caught up with them, and over the past few hundred thousand years many populations of animals and plants have vanished without obvious human assistance.

Another difficulty with assessing the ecological impacts of our early ancestors comes not from ancient evidence but from some of the modern notions that have become associated with ancient lifestyles and the people who follow them. At one end of the opinion spectrum lies the assumption that people who live "within nature" have an innate wisdom that leads them to preserve the things they depend upon for survival, while at the other extreme is the rather cynical notion that "primitive people" have little potential to do much damage regardless of their intentions. These are interesting subjects for debate, but among our early ancestors what mattered most was the struggle to survive and contribute to posterity, which would have directly influenced many aspects of their dealings with each other and their natural surroundings. The details of the struggle would have varied from group to group and from place to place, yet there would have been some universal aspects, including one our erectine ancestors would have been familiar with: success.

The simplest way to account for the rapid spread of people like us across the globe and into many different natural situations is that our ancestors were doing what comes naturally when mobile and adaptable creatures encounter increasingly intense competitions for the necessities of life. Without discounting their pioneering spirit, we can say from Darwinian principles that it would have made no evolutionary sense to explore the world just for the sake of adventure, especially when the exploration involved life or death risks such as striking out into the open sea on small boats or migrating into unknown territories along dangerous routes; for example the land bridge from north-eastern Asia to northern America seems to have been traversed several times when it was exposed by partial glacial melting. Those risks would have ensured that many pioneers failed in their search for new homes or ended up in places where they were barely able to survive, but those who stayed put also risked running into local limits to growth and the deleterious consequences of crowding (e.g. epidemics), stressed environments and natural disasters. Thus it is reasonable to assume that the wave of modern human migration would have continued to advance whenever and wherever people were able to establish and maintain relationships with each other and their natural surroundings that supported population growth, because growing populations would have supplied both the pioneers needed to continue the search for new opportunities and the incentives to pursue that quest.

To make a long story short, it may be difficult to retrace the initial dispersal of the nomadic founders of modern humankind, but we can be reasonably certain that those who made the most significant contributions to posterity owed their success to a combination of adaptability, ambition, adventurousness and luck. As for any malignant tendencies that may have existed among them, it is difficult to see how such inclinations or those who expressed them could have gone very far, since people who had difficulties working together or dealing effectively with other groups or their natural surroundings would have had poor prospects for facing challenges, exploring opportunities or competing with those who were more in tune with their social and natural situations. Thus it is reasonable to assume that our most successful nomadic ancestors would have behaved as if they understood the importance of remaining on good terms with each other and the world around them.

The preceding statement was not meant to be cryptic, it simply points out that our assumptions concerning how our early ancestors would have been obliged to behave do not tell us much about what they may have actually been thinking. We can reconstruct the ancient Darwinian landscape because we know that our ancestors' interactions with each other and their natural surroundings would have been critical to their survival and competitive success, but when it comes to the ancient Freudian landscape the best we can say is that like us, our nomadic ancestors would likely have behaved in ways that were informed and influenced by complex and unique combinations of hereditary, intellectual and cultural factors such as instincts, habits, traditions, attitudes, experiences, insights, knowledge, beliefs and theories. This may not bring us any closer to understanding what our ancestors were thinking but it does introduce a few things to keep in mind as we consider how and why some of them embarked upon the evolutionary journey that is commonly known as the road to civilization.....

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The Magic Cycle of Civilization

We made a start on the genesis of large societies in the preceding chapter, and in our journey back to this point we have hopefully managed to set the scene a bit better with regards to how and why some of our ancestors blazed a trail which has been retraced and recreated many times since. Before we pick up the story again - which thanks to our earlier efforts can be kept brief - this may be a good place to recall the point made at the beginning of this chapter regarding progress. None of the developments we have encountered during our survey of human evolution were inevitable, universal or progressive in the sense of being the products of preordained plans or innate drives toward perfection. Indeed the use of the term development is itself problematic, since the idea of change moving in a particular direction is commonly linked with the notion of something guiding that change from without and there is no need to invoke such guidance for any of the changes we have associated with human evolution to this point. The developments we have highlighted can be most simply depicted as the products of survival and chance, challenge and competition, and a uniquely potent combination of adaptability, success and opportunity - a combination that provided the momentum for the rapid rise of modern humankind to mastery of the hominine world, drove the irresistible spread of our nomadic ancestors across the globe and encouraged some of them to develop new lifestyles based upon ecoconversion. In keeping with that pattern, history also tells us that the most successful, adaptable and fortunate practitioners of the new lifestyles became the founders of the earliest large, dense and complex human aggregations we know of.

A key aspect of their good fortune was something all realtors appreciate: location. The earliest civilizations arose in places that were alike in many ways, and their essential qualities are captured in the name of the region that has long been acknowledged as the cradle of civilization: Mesopotamia, the land between the rivers. These were not just any rivers; those that spawned major population centres along their banks - a list that includes the Tigris, Euphrates, Nile and Indus - tended to be large, tropical and bounded by alluvial plains which were often inundated during seasonal floods. Such locations make sense when we consider that the populations which emerged along the banks of such rivers gained much of their sustenance from growing crops that flourished in places with long growing seasons, ample supplies of fresh water and sunlight, and soils rich with the kinds of essential nutrients that are abundant in alluvial regions and continually replenished by silt deposited during floods. The lower Nile valley, for instance, received an annual dose of nutrient-rich muck carried down from the upland forests which produced a strip of land so fertile that even inefficient agriculturalists would have been able to do quite well, as they appear to have done for many generations beginning around 7000 BC.

While they were undoubtedly fortunate in their choice of locations, the people who blazed the trail from settlements to civilizations were also ambitious and ingenious. For instance the Mesopotamians came up with technological advances like irrigation systems, land reclamation techniques and animal-drawn ploughs, they discovered and selected high-yielding crops like barley and bread wheat, and they learned how to combine these elements within highly productive ecosystems; for example some of the wheat-growing regions of ancient Mesopotamia have been estimated to have been as productive as those of the modern Canadian prairie. All early societies also show signs of significant innovations in the social sphere, with one of the more prominent trends being the division of traditional labours and duties among individuals, groups and communities, and the creation of a variety of new social roles, relationships and organizations, including the defining novelties of the age, towns and cities.

So here we have the basic ingredients of the earliest large societies: ecoconversion, prime locations, growth and technological and social innovation. One thing that would not have been necessary was an overall plan, since there is no reason to think that the people who blazed the trail to civilization were doing anything more than responding to the challenges, pressures and opportunities they encountered in the course of a journey which from their perspective had no goal or purpose beyond survival and success. We can get a feel for their situation by returning to - you guessed it - some of the descendants of our hypothetical settlers, who through luck and ambition have landed up in a place with ample amounts of land suited to the establishment of somewhat more productive ecosystems than those their ancestors inhabited.

In fact, thanks to a few modest recent improvements in farming techniques several communities have reached the point where they can grow more than enough food to support themselves even without having everyone work full time in the fields. The food surplus has allowed communities to start setting by emergency supplies of grain as a hedge against hard times, and they have also become involved in an extensive regional trading system; for example farmers on the alluvial plains swap grain for fish and salt brought in from farther downstream. The relaxation of farm labour demands has also allowed some settlers to explore other occupations, some of which have helped those who remained on the soil to work more effectively. For instance a few of the more able craftsmen have specialized in manufacturing and maintaining cultivating tools, and in constructing and operating irrigation systems, some of which have reached the point where they are allowing farmers to raise an extra crop during the dry, sunny summer months.

With a modicum of speculation we have allowed our hypothetical population to reach a point where it is changing in ways that have the potential to encourage and contribute to increases in agricultural productivity, co-operative social elaboration, population growth and food and labour surpluses, some of which are likely to be invested in further improvements in productivity and co-operation, which may encourage and contribute to.... In other words, the population seems to have encountered an evolutionary dynamic where the same changes that contribute to growth, ecosystem expansion, improvements in productivity and the elaboration of social organizations also have the potential to encourage further changes in the same directions. Like the other dynamics we have associated with human evolution this one seems to have the potential to produce rapid developments in particular directions; indeed it is so potent that if we check in on our hypothetical settlers after a few generations we will not be surprized to find some striking changes. For instance the descendants of some of the handymen and craftsmen may have become employed as builders, engineers and architects, who are involved with the construction, operation and improvement of irrigation networks, habitations and other structures. One of those structures may be a formidable walled citadel into which the local population periodically retreats when threatened by their increasingly belligerent neighbours, and its fortifications are likely to be manned by professional soldiers who occasionally call up conscripts from the small farming villages where much of the population still lives. The produce of those villages may also support other specialized centres such as ports, ritual complexes, monasteries and palaces, where many inhabitants have assumed novel social roles that include traders, manufacturers, service specialists, officials, managers, civil servants and astronomer-priests whose ritual calendars co-ordinate all aspects of life within the burgeoning society, from planting and harvesting to sacrifices and war.

These developments are of course typical of those that history tells us appear to have unfolded in situations where ancient agricultural populations had plenty of room to grow and the luck and ability to make the most of their opportunities. In some cases it seems to have taken only a few generations for populations to expand, herds to multiply, ecosystems to be extended and made more productive, villages to become towns, towns to become walled cities, farmers to become peasants, shamans to become high priests, weekend warriors to become soldiers, chiefs to become kings and for many people to find completely new ways of making a living while learning how to coexist in close quarters and co-operate in ways that contributed to further growth and success. Even by human standards these developments were rapid and unprecedented, and within the context of the living world they were truly marvellous. In almost no time at all as far as the geological clock goes, representatives of a lineage that had been modestly successful at nomadic hunting and foraging began to shift from a life strategy based upon integrating into living communities and landscapes to one that involved dominating and reshaping them, and that transition had scarcely gotten underway before populations appeared that set about building huge, fast-growing, highly concentrated and enormously complex ecological and social organizations unlike anything the world had ever seen.

To say that these developments were magical is not to imply that early ecoconverting populations or the societies they gave rise to were liberated from the challenges that all living things must face in the struggle to survive, nor that their success became independent of the considerations that applied to their ancestors, such as the necessity of establishing and maintaining natural and social relationships that were both productive and sustainable. Indeed far from being freed of cares the builders and constituents of the first large societies would have faced most of the challenges their ancestors had to deal with plus a host of new ones, such as those associated with maintaining the sustainability and stability of ecosystems and social organizations that were expanding and changing so rapidly they were beyond the ken or control of individuals or traditional social groupings. For example as people and their domesticates became increasingly numerous and concentrated they would have faced rising risks of crowding complications such as outbreaks of diseases, while the potential consequences of environmental fluctuations and sporadic disasters like earthquakes, floods and storms would have been magnified considerably. Large populations and societies would also have created new challenges and opportunities for each other as they developed and interacted, with the possibilities ranging from co-operation (e.g. trade) to lethal competition (more on this in a moment).

Thus while its results may have been spectacular there is no reason to think that the "magic cycle of civilization" was either automatic or irresistible - indeed our considerations would lead us to expect that the extent to which it would have been able to proceed in any given situation would have depended upon a host of natural and human factors. It is likely that in many cases the cycle stalled before anything resembling a civilization was produced, and since those societies that did make the ascent would have faced continual and oftentimes multiplying and/or intensifying challenges to their success and survival, there is every reason to expect that many a meteoric rise may have been followed by an equally dramatic decline. Here again, history does not disappoint. It tells us that many agrarian populations failed to sprout large societies and many civilizations did not last very long. We can get an idea of some of the challenges that were associated with the success and survival of early large societies by briefly considering two prominent examples, one widely acknowledged to be the first and the other recognized as among the most durable......