What a Wonderful World (10 page)

It is worth pointing out that, although Africa is widely considered the cradle of human evolution, it is quite possible that some of that evolution occurred outside Africa among hominins that then
returned to Africa
. At present, however, the fossil record is too coarse to reveal such fine detail.

The huge evolutionary changes in hominins are, as far as we know, unprecedented in any animal in the history of life on Earth. They coincided with the repeated advance and retreat of ice from the Earth’s polar regions over the past 2 million years. Ice ages are generally caused by cyclical changes in the orientation of the Earth’s spin axis and orbit. But what appears to have magnified these Milankovic´cycles
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– named after Serbian astronomer Milutin Milankovic´who discovered them – over the past 2 million years is the rise of the mighty Himalayas, which changed the circulation of the air around the globe. The connecting up of North and South America also closed the tropical channel through which water could be exchanged between the Pacific and Atlantic oceans, boosting a north–south flow.

Living on a planet that repeatedly iced up, hominins were continually subjected to stress by their environment, becoming extinct in cold northern regions and surviving only in regions
nearer the equator. But, unlike all other creatures on Earth, whose response to advancing ice was merely to migrate to less harsh climes or to go extinct, our human ancestors were unique in having an ability to change their behaviour in response to their changing environment. Early on in their history, being adapted for change might not have been enough for them to cope with very rapid climate change. But, later on, as their culture became more sophisticated, they adapted caves as shelters from the cold; fashioned clothing out of animal skins, and harnessed fire.

Nobody knows when and how fire was first tamed. There is disputed evidence from South Africa that it happened as long ago as 1 million years but good evidence exists only as far back as a few hundred thousand years. Probably, the first fire to be used by humans was a natural fire. Someone, on a bitterly cold night, carried a smouldering branch – ignited perhaps by lightning – into the mouth of a freezing cave. Only much later did people learn how to
make
fire. This is a difficult skill that, even today, very few people possess. It is possible that the secret of making fire was discovered and lost repeatedly whenever someone who knew the secret died.

This might throw some light on why technological progress such as improvements in tools was so slow for enormously long periods of time before there were explosions of creativity. As long as our ancestors lived in small, scattered groups, knowledge might have been gained, lost, gained and lost again, repeatedly. Only when hominin numbers swelled sufficiently was there a chance of ideas surviving, spreading and spawning new ideas.

Fire made possible cooking, arguably one of the most important developments in human history. Cooking detoxified some plant poisons, boosting the range of plants that could be eaten safely, and it killed parasites in meat. But, most importantly, cooking broke down the proteins in meat so that they were easier to digest, doing some of the work of the gut. Just as a tool is an enhancement of a limb, a cooking pot is an enhancement of the stomach. More than that, it is an
external stomach
. It means that the stomach can be smaller, and less energy-hungry. And this frees up yet more energy for the insatiable needs of an ever-growing brain.

Since
Homo erectus
had small teeth and small jaws, it is possible that as early as 1.5 million years ago it was cooking its food. The first strong evidence of cooking, however, is from Neanderthals and early modern humans about 200,000 years ago.

In the icy world, our direct ancestors came up against many of their hominin cousins. It is striking that none of them has survived. Most intriguing is the case of the Neanderthals, descendants of an earlier wave of colonisation of the world. Being shorter and wider-bodied than modern humans, they were built for the cold. They made tools, buried their dead and, for a long time, appeared to be thriving. They probably had language, which is believed to have originated at least 500,000 years ago. However, their vocal regions indicate that they might have uttered a smaller range of sounds than humans and that the sounds might have been higher pitched. Ultimately, however, Neanderthals died out, their last known outposts being caves on the southern coast of the Iberian peninsula.

There has long been a suspicion that Neanderthals were wiped out by modern humans. The truth, however, might be more subtle. For instance, about 2.5 per cent of the DNA of modern humans living outside Africa is believed to be Neanderthal, indicating that there was interbreeding between the two species. It might be that our ancestors had a small 1–2 per cent competitive advantage over their cousins. Magnified over many, many generations, this could have seen them monopolise ever more territory and game.

One such advantage that humans had over Neanderthals was …
sewing
.

Human needles are found from about 40,000 years ago. But no Neanderthal needle has ever been found. Being able to sew enabled our ancestors to make better clothes. Better baby clothes might have ensured that, in a bitter cold snap, human newborns had a slightly higher chance of surviving than Neanderthal neonates. It could have been just enough to see humans prosper at the expense of Neanderthals.

By about 50,000 years ago,
Homo sapiens
was king. Probably, no hominin species had ever amounted to more than about 10,000 to 100,000 individuals – at the most, a million. But, by 2012,
Homo sapiens
had expanded to 7 billion individuals, filling every niche on the globe and threatening the survival of every other species on Earth.

Some biologists argue that evolution has now stopped for human beings. We have adapted our environment to us and no longer need to adapt to it. But this ignores the fact that most people,
apart from those in the affluent Western world, face a daily battle for survival as challenging as that faced by their ancient hominin ancestors. Even in the West, the demands of an ever more complex and connected world must be having a profound effect on the wiring of our brains.

Science-fiction writers have often envisioned humans of the far future as having big brains and stick-like, atrophied legs. But this is to ignore the lesson of fossil history.

Cro-Magnons, our ancestors in Europe, had bodies and brains between 5 and 10 per cent bigger than ours. The reason for this might have been that a bigger body was a stronger body, able to protect itself and ensure survival. And, every second of every day Cro-Magnons had to worry about survival, whereas today many of us live in a more benign world where someone else does the hunting, someone else supplies the food. Tellingly, domesticated animals invariably have smaller brains than their wild cousins. ‘Through culture, humans effectively domesticated themselves,’ said paleoanthropologist Louis Leakey.
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Whatever the reason for the rapid shrinking of people after Cro-Magnons, the trend is clear. Contrary to expectations, the humans of the future will probably have brains that are not bigger than ours but significantly smaller. Of course, whether we actually have a future depends on our solving a multitude of global problems, many of our own making. It is here that we confront the sobering lesson of our past. For as the American biologist Edward O. Wilson said, ‘We have created a Star Wars civilisation but we have Stone Age emotions.’
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The human story did not of course finish with the ice ages. The ice spread down from the poles; the ice returned whence it came. Over and over again, ebbing and flowing like a mile-deep white tide. But then, after the ice had retreated and the sea level had risen for the umpteenth time, something changed in the world. The change was so profound that the train of events it set in motion could conceivably prevent the return of the ice. Not for a while. But for ever.

The development was, of course, farming.

For thousands of generations, humans had no choice but to eat what produce nature laid out on its table. As hunters, they had followed the great herds of game. As gatherers, they had picked fruit and berries from bushes and trees. But, around 8500
BC
, in the south-west corner of Asia, there appeared something entirely new under the sun: a fresh and innovative way of living.

The Fertile Crescent is a band of biological abundance whose epicentre is the land between the Tigris and Euphrates rivers in present-day Iraq, Syria and Turkey. Among the plants that thrived there were wild grasses with big edible seeds. No doubt people had grazed on these cereals for as long as they had grazed on other berries and fruit. In fact, since the plants often grew in large stands, people might have begun to rely on them for a significant part of their diet.

Around 12,000
BC
, the world was still in the grip of intense cold, but the ice age was beginning to falter, and its last millennium was punctuated by spells when the climate warmed just a little. During one of these spells, according to British archaeologist Chris Scarre, people began to do something they had never done before. The details are sketchy. Perhaps they uprooted cereals and replanted them in moist rich soil close to one of the big rivers. Or maybe they simply weeded out competing plants in order to leave a field that was exclusively covered in cereals.

In the beginning, the cereals selected for special treatment were indistinguishable from their wild versions. But something subtle that people did began to change everything. They planted only the wild cereals with the biggest seeds and the easiest-to-remove husks. And, when they harvested their cereals, they replanted only the cereals that had borne the biggest seeds and whose husks popped open most readily. Gradually, because of these actions, the seeds grew bigger and easier to harvest season by season.

Inadvertently, without the slightest idea of what they were doing to the DNA of their crops, the farmers of the Fertile Crescent had become the first genetic engineers, exponents of evolution by human, or artificial, selection. Natural selection was not completely cut out of the equation. The plants that thrived were precisely those that could best tolerate the artificial environments created by humans – plants that grew fast even when exposed to the baking sun in unshaded fields or which grew strong when packed close together in rows. But, whether it was natural selection that was operating or human selection,
it was operating to a human agenda
. For the first time in history, people were directing the evolution of other species.

By 8500
BC
, the cereals had diverged so significantly from their wild cousins that they were a different species. Wheat had become domesticated. And it was not alone. By 8500
BC
, people had domesticated pea and olive too. And these were just the first of many domesticated crops that would follow over succeeding millennia. Modern agriculture had begun and nothing in the world of humans,
nothing in the world
, would be the same again.

An obvious question is why did farming start in the present interglacial and not in the previous one, between 130,000 and 115,000 years ago? A possible answer is that humans at the time had not yet evolved the intellectual capacities and imagination of fully modern humans. The sudden flowering of art across the world around 50,000
BC
is often taken as evidence of a profound change in the wiring of human minds.

The changes brought about by the shift to growing food were profound. For the first time in history, people were able to live their whole lives in one location. Instead of brief overnight halts around campfires, they were able to stop for good in permanent settlements. That is not to say that that there had been no settlements before. People might have been able to stay put if, for instance, they were close to an abundant source of food such as a fish-filled lake. Farming, however, made it possible for a lifestyle that had been a rare exception to become widespread.

But the key change was not the creation of settlements but the creation of a food surplus. Farming can typically feed between 10 and 100 times as many people per square kilometre as hunting
and gathering. The surplus of food meant more people could be supported, which meant the population could grow. Ironically, this growth inevitably meant that the food was spread ever more thinly, so, in the long term, people might actually have been more badly nourished than their hunter-gatherer ancestors. But, by this time, there were too many people per square kilometre to be supported by the old lifestyle. The point of no return had been passed and there was no going back.

The surplus of food meant not only that more people could be fed; it meant that not everyone needed to be engaged in obtaining food. For the first time it was possible to support non-productive people such as craftsmen who made bricks or pottery or jewellery.
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Of course, craftsmen could not exist without a market for their goods. And here the new developments fed off each other. The sedentary lifestyles permitted people to clutter their homes with belongings. By contrast, hunter-gatherers, continually on the move, were limited to what they could carry – a baby or a handful of spears.

But the food surplus, in addition to supporting craftsmen, could also support soldiers whose job was to defend a settlement and its fields. And not only soldiers but a chief. Hunter-gatherer societies tend to be egalitarian.
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However, settlements of many people are complex. And, just as the myriad functions of a cell need to be orchestrated by a central nucleus, the myriad functions of a village need to be orchestrated by some kind of central government. The control of people by such a ruling elite, with soldiers at its disposal, provided both dangers and opportunities. Inevitably, it would lead to conflicts over land and resources. But it would also spawn cities and, eventually, empires of hundreds of thousands, even millions, of souls.

Such vast accumulations of people were an extraordinary and unprecedented thing. Our great-ape cousins live in small bands and react violently to outsiders. Initially, humans might have shared their xenophobia. But, as communities grew in size, people had to overcome their knee-jerk instinct to lash out at others. Benjamin Franklin spelled out the recipe for living in large communities: ‘Be civil to all; sociable to many; familiar with few.’ The key importance of this was recognised by Sigmund Freud. ‘It is impossible to overlook the extent to which civilisation is built up upon a renunciation of instinct,’ he wrote.
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Natural selection was probably operating here too. Those settlements where people were best at living in close proximity to each other without running amok had the lowest death rates and so grew faster than others. Their numerical domination meant that, over time, people became ever more passive and tolerant of each other. This is the view of Canadian-born psychologist Steven Pinker, who argues that, despite millions dying in the world wars of the twentieth century, the human race has shown a marked trend towards becoming less violent and warlike.
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‘Civilisation is just a slow process of learning to be kind,’ wrote Tennessee Williams.

People might have actually gone so far along the road to getting on with each other that they now choose to flock together in cities where they can interact with many others. ‘People
like
being with other people,’ says Scarre. Charles Dickens, who found himself living at a unique time when nineteenth-century London was making the transition to a mega-city of many millions, was one of the first to notice the new opportunities for interactions between large numbers of people. It might explain why in his novels chance encounters play such a big role.

The growth of societies and the growth of their complexity eventually triggered another profound development in human history: the invention of writing. This did not happen overnight. At first, the wedge-shaped marks made on clay tablets by the Sumerians around 3400
BC
recorded only dull commercial transactions. But basic cuneiform was superseded by written languages that could express non-utilitarian things such as thoughts and feelings. Just as the cooking pot acted as an external stomach, the written word acted as an external memory. Whereas only a small amount of knowledge could be transmitted between people verbally, an enormous amount could be now transmitted in written form. By means of writing, the human race acquired a collective brain. Its full awakening would require widespread literacy, which would take many millennia. But, even in the earliest days, the writing was on the wall (pun intended).

So far, I have not mentioned animals. But, of course, the first genetic engineers did not simply manipulate plants. They captured and tamed large mammals and bred them for passivity or meat content. In the process, animals too diverged from their wild cousins and became domesticated. Not only did they provide food but they provided the motive power to pull ploughs to break up the hard soil and to pull goods on wheeled carts. The first animals to be domesticated, again in the Fertile Crescent, were sheep and goats around 8000
BC
. In China, pigs and silkworms were both domesticated by 7500
BC
, along with rice and millet.

The importance of animals to humans cannot be overestimated. Everywhere in the world where there are people
animals live with them, not just as walking larders but also as pets. The American anthropologist Pat Shipman argues that our relationship with animals is central to understanding the extraordinary success of humans.
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She points out that, from the moment humans first became artists around 50,000
BC
, they rarely depicted themselves or their environment. Instead, almost exclusively, they painted prey animals. Their stunningly vivid representations, perfect in every anatomical detail, reveal what fantastically keen observers of animal behaviour they were. And it was this intense studying of animals, Shipman argues, that enabled humans to out-think their prey. It is the key, she believes, to understanding how a puny and insignificant ape, outrun and outgunned by big predators on the African savannah, managed to gain such control over its world.

Controversially, Shipman even believes that language might have arisen in order to exchange knowledge about animals. She believes this explains why humans domesticated an animal such as the dog, which is rarely eaten and which actually competes for the very same food resources with humans. Dogs were domesticated at least 17,000 years ago and possibly as early as 32,000 years ago.
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The fact we keep pets, Shipman believes, reveals a profound important truth: without animals, humans are not humans.

Together, the domestication of plants and animals can be categorised as the invention of food production. This was the post-ice-age revolution that transformed the human race. Everything that has happened since has been a consequence of it. The birth of a sedentary lifestyle, first in villages, then in cities. The birth of specialised jobs. The creation of ruling elites. The birth of writing. The invention of war and creation of empires.
In 8500
BC
, a ball was set rolling that was unstoppable and that to this day is continuing to gather momentum.

There have been so many milestones along the road to the world of the twenty-first century that it is hard to know what to mention and what to leave out. But some of the most important developments occurred from the late fifteenth century onwards. Very significant was the advent of ships that could cross oceans, connecting Europe to the Americas, Africa, Asia, and finally Australia. This marked the beginning of a truly global civilisation. Later, towards the end of the eighteenth century, world trade was boosted enormously by mechanised factories that could mass-produce goods. This industrial revolution was powered first by water, then by coal, an energy source around 150 times more potent than human muscle power. Having access to such energy sources is one of the reasons that only a few per cent of the population are able to provide food for the overwhelming majority.

A development just before the industrial revolution, however, was also hugely significant. The rise of science, in the seventeenth century, illustrates how the collisions between ideas or technologies can spawn new ideas and new technologies. For thousands of years there had been craftsmen. By getting their hands dirty, they discovered how to make harder swords or better clay pots. But they worked by trial and error and never created a
theory
of what they were doing to guide them in finding ways to do it better. Besides the craftsmen, there were natural philosophers. Beginning with the Greeks more than two and a half millennia
ago, they theorised loftily about the world but did not get their hands dirty in order to test their theories. What changed in the seventeenth century was that these two separate rivers of human expertise flowed together and became an unstoppable flood: science.