Meanwhile, Homo sapiens moved up into Europe during a brief interval in the larger cold phase between 58,000 and 28,000 years ago, and adapted well. They were lighter than Neanderthals, needed fewer calories to survive, and were more omnivorous. And they weren’t against an occasional meal of fish or even a vegetable or two. They hunted with lighter stone-tipped spears that could be thrown at a distance. They also used spear throwers (atlatls), which consisted of a shaft with a cup at the end into which the spear fit, giving the hurtler and his spear additional leverage, distance, and velocity. Using a thrower, a human could toss a spear up to 325 feet (100 meters), though it was most effective and mortal at about half that distance.
The end came for Neanderthals during the period when Homo sapiens were undergoing their grandest growth—an explosion of culture, symbolic communication, and art. While the communities of modern man grew, Neanderthal communities remained small, and the range of their influence was smaller, too. Neanderthals were lucky to collect stones sixty-two miles (one hundred kilometers) away, while Homo sapiens collected stones up to three hundred ten miles (five hundred kilometers) away.
“Homo Sapiens had the ability to develop trade at a much greater distance than Neanderthals,” says Rick Potts, director of the Smithsonian’s Human Origins Program. “Our species can get something five hundred kilometers away, or develop an alliance with someone five hundred kilometers away. In the end, that can really buffer bad times.”
Neanderthals gradually disappeared from Britain, Greece, the Middle East, Russia, and Mongolia. Their last stand may have been in the caves beneath the Rock of Gibraltar. Did the Neanderthals go peacefully, or were they pushed over the evolutionary cliff? Scientists believe that early hunter-gatherer societies were more aggressive than previously judged.
One of the biggest advantages Homo sapiens may have had over other hominids was language. Language gave moderns the ability to pass on the lessons of the past. Communication and the ability to remember and utilize a broader range of information allowed for innovation. “And Homo sapiens had the ability to accumulate innovation,” says Rick Potts. No other species had demonstrated this before.
The ability to understand language may have actually preceded the ability to talk. Beneficial mutations in the genetics of understanding may have come before mutations in the ability to mouth words. Thus scientists have had luck getting primates, chimpanzees, orangutans, and bonobos to understand language but less luck getting them to talk.
Robert Shumaker, vice president of conservation and life sciences at the Indianapolis Zoo, told me that there have been several studies aimed at getting monkeys and other primates to speak English. Vicky, a chimpanzee raised by scientists in the early 1900s, was trained to vocalize breathy imitations of “Mama,” “Papa,” “cup,” and “up,” but the efforts were laborious and the lessons soon forgotten. Great apes simply don’t have the morphology to form English words. However, Bonnie, an orangutan that Shumaker worked with at the National Zoo in Washington, DC, demonstrated a series of whistles that she used to let caretakers know her needs. “And she did this without training, essentially creating her own vocabulary and syntax to go with it,” says Shumaker.
Experiments at the think tank at the Smithsonian National Zoological Park in Washington, DC, display this innate ability. Chikako Suda-King, on a postdoc fellowship with the David Bohnett Foundation at the Smithsonian, took me behind the scenes one autumn day to meet the famous Brainy Bonnie, the orangutan that Shumaker had worked with. When Suda-King walked into the cage area, Bonnie started to act like an excited kid, but soon grew serious when she saw Suda-King roll a computer up in front of her cage. She promptly settled down in front of her computer screen.
Suda-King was trying to determine if Bonnie had the ability to make decisions based on the perception of her own knowledge of a given subject. In other words, was she capable of asking herself: Do I know enough to take this test? This is a level of self-awareness that was previously thought unique to humans. On this day Suda-King presented five pictures, all of the same thing, which the orangutan individually tapped to move forward in the game. The next screen gave Bonnie a choice of two pictures presenting options that she had learned to translate as follows: Do you want to go to a second test of your recall of those photos and get three grapes, or do you want to opt out of the test and take only one grape? If the animal chose to take the test and missed, she got nothing. During the test phase, she was shown several photos; only one was similar to those in the study phase.
Bonnie picked the test over and over, and consistently matched the correct photos. Suda-King, who holds a PhD in animal psychology, had to slip Bonnie her three-grape rewards through a slot between them, and today Suda-King was having trouble keeping up with the orangutan. “We’re going to have to make this test harder for her,” she joked, though she admitted it had actually taken Bonnie a couple of years to figure the test out. Still, it proved self-awareness in a primate.
Sue Savage-Rumbaugh, a research scientist at the Great Ape Trust in Des Moines, Iowa, claims her bonobos, relatives of chimpanzees, are able to communicate with caregivers through human sign language and a system of lexicons. Savage-Rumbaugh says her bonobos are allowed to watch soap operas, which they select and turn on themselves, and they have shown a preference for sequential stories.
Lisa Heimbauer, a doctoral candidate at Georgia State University, taught a chimpanzee called Panzee to understand English by treating the chimp like a human from shortly after it was born. Panzee can currently understand 130 human words even when those words are offered in computer-distorted speech that was thought to disguise those words from anyone other than humans. Heimbauer believes that primates developed understanding before speaking. “The cognitive abilities to perceive speech had to be there when production evolved,” she told me in a telephone interview.
Though both Neanderthals and Homo erectus are thought to have had some form of basic speech, Homo sapiens were better at acquiring and advancing it. This gave them a dramatic advantage over other hominids because they could engage in trade while learning to navigate the wildly fluctuating climate of the ice ages. In The Third Chimpanzee: The Evolution and Future of the Human Animal, Jared Diamond describes this as the “Great Leap Forward,” or the dawn of culture. Speech involves a series of mental images or symbols that represent words and thoughts. Though there is no direct evidence of speech in Neanderthals, there is evidence of common tool use that must have required some sort of communication between the different hominids, and possibly interbreeding. The latter may be responsible for shared genes in both species, particularly the FOXP2 speech gene, which anthropologists say Homo sapiens may have picked up from Neanderthals.
Speech may have given modern man the same advantage that large lungs gave Lystrosaurus, the bulldog with tusks, during the Permian extinction. Like man, Lystrosaurus grabbed this advantage and populated much of the world, as did the newly evolved dinosaurs after the Triassic extinction: they seized the advantage from the then-dominant crocodile-like predators, and soon ruled the world.
Today, modern man is the planet’s most successful creature, occupying virtually every environment on earth except the deep ocean and the polar ice caps. But our population growth of Homo sapiens has reached a zenith in the last fifty or sixty years, and we are now at the point where our celebrated progress has become our greatest nightmare.
The population boom of Los Angeles, California, shows how growth can rapidly accelerate with little notice by the residents but with great consequences for the environment. The town was established in 1781 when the Spanish governor at the time convinced 44 people to come up from Mexico to investigate the possibilities of this new and untrammeled land. By 1800, the 44 people who had settled there grew to 315 people. By 1850, after Mexico had ceded California to the United States, there were 1,610. By 1900, there were 102,479. Then they found oil in some of the beach towns. In the 1910s and 1920s the film industry moved from New York out to t
he West Coast for better weather. With the breakout of World War II, they started building planes. By 1950, in an area of about 502 square miles—smaller than London or Tokyo but bigger than New York—there were 1,970,358 people living.
I grew up in Los Angeles’s Westside when it was mostly single-family dwellings. Traffic on the street was light, and there were few freeways. Then the government started building freeways and moving my friends out, buying up their property for public use under the government right of “eminent domain.” Over time, the single-family dwellings turned to multiple dwellings. The former apartments turned to apartment towers. My family used to drive east toward the mountains or the desert and we would gaze at orange groves all along the way. Now there are homes, apartments, car lots, and mega-malls. Today the population is close to 3.9 million. And most of this growth, both the human population and the infrastructure, developed in the last one hundred years.
A similar tale of growth is true for New York City. When the surveyor John Randel Jr. submitted his intricate grid of the streets of Manhattan in 1811 that would eventually develop into Greenwich Village, SoHo, Times Square, and all its famous communities, this central isle surrounded by rivers was but a New York City borough of eighteenth-century villages. “The island was hilly and stony, woven with creeks, soft in places with beaches, marshes, and wetlands,” writes Marguerite Holloway, author of The Measure of Manhattan, the story of Randel’s grand achievement. In 1800 the city’s population was 60,000. Today the Census Bureau shows New York is the most populous metropolitan area in the US, with an estimated 8.4 million residents.
In those two hundred years, London has grown from about 960,000 to 2.8 million. In one hundred years, Tokyo has grown from 3.7 million to 13.2 million. Istanbul grew from 3.7 million to 13 million. When you include the immediate suburbs around these cities, estimates can more than double. As the population of the world has risen, so has the population of its great cities.
If we were to make a chart of the world’s population growth, it would look a lot like the Keeling Curve, which shows the growth of CO2 in the atmosphere in the last thousand years. It’s often referred to as a hockey stick, because CO2 emissions remained steady for most of this period until 1850, when the Industrial Revolution swung into gear worldwide and amounts grew from 280 ppm (parts per million) to 396 ppm today. The world population in AD 1 was about 200 million. It increased slowly over the first millennium, but started accelerating in the second millennium, particularly toward the end. By around 1800 it was at 1 billion. By 1930 it was 2 billion; 1987, 5 billion. By 2011, 7 billion. By 2024, it is predicted to reach 8 billion, and by 2045, 9 billion. If the world continues to grow as it has in the last fifty years its population could reach 27 billion by the year 2100, which is unsustainable. Among a ton of other issues, there simply wouldn’t be enough food to feed that many people.
Population experts are relying on a radical slowdown of this growth brought on by national controls, but also by women holding off childbirth to take advantage of increasing opportunities in industry and education. Many scientists project that population growth could start to level off during this century, and by 2100 we may be only ten billion. Still, that figure represents three billion more people on earth than there are today.
The largest population growth has occurred in Asia and Africa. From 1960 to 2011, India gained 782 million people, the single largest contribution to the planet’s population in the world. By 2030, India’s population is expected to top China’s. In India, women have an average of 2.5 children each. But by 2030 the rate is expected to fall to 2.1 children, close to the replacement rate of 2 per couple. The problem is that over the last fifty to sixty years we’ve come through the largest population boom in the history of man, and this has momentum. United Nations demographers used to think it would peak in 2075. Now they say it will continue to grow into the next century.
There are cultural barriers to population control. Fertility is still advanced by tradition, religion, the lower status of women, and limited access to contraception. In the US, support for family planning has actually dwindled. Population growth today gets less attention than it did in the 1960s, when there were only half as many people alive.
India’s population growth has slowed among the urban middle class but remains high among the rural poor. Producing a male heir is still a family tradition in the Hindu culture. Sons provide for their parents in old age and perform last rites, a duty seen as necessary for access to heaven. Having ten or fifteen grandsons is still considered a healthy sign by some Indian grandparents.
China’s one-child policy has slowed growth there, but the momentum created by hundreds of millions of young Chinese still in their reproductive years continues to be a force in the other direction. The country’s current population is 1.3 billion. Today young couples are given housing subsidies as well as retirement benefits if they hold to one child. But even if they don’t have more children, they are still consuming larger portions of the country’s resources in terms of food, energy, and goods as their economy grows.
Population growth in Southeast Asia and the Middle East fuels strife. In rapidly developing countries, young men can’t find employment. However, some can make a living ambushing military vehicles or foreign supply trucks and dividing up the food, blankets, and spoils. Population experts say that 80 percent of the world’s strife since the 1970s has been driven by the explosion of youth.
Without employment, young men can’t save money for a dowry, without which many in the Middle East and Southeast Asia can’t get married. And their culture places heavy penalties, even death, on sex outside of marriage. An enormous youth population denied employment, money, and sex is a formula for disaster.
Two billion more people may be added to the world’s population by 2050, and most of them will come from the poorest countries in Asia, Africa, and Latin America. Security assessments by the US National Intelligence Council warn that climate change could harm food, water, and natural resource supplies, which in turn could lead to global conflicts.
Some say population growth may level off in the next hundred years, but this wouldn’t include human consumption of natural resources. Third World nations that are becoming industrialized want some of the benefits afforded to those that arrived earlier—like cars, electronics, and meat. Modern estimates for how many humans the world could support range from a high of 33 billion for people fed on minimum rations only, down to 2 billion if they all lived like middle-class Americans, a style of life many pursue because they watch it on television.
The Population Bomb was a book published in 1968 by Paul R. Ehrlich, a Stanford University professor, that warned of mass starvation as the result of overpopulation. The book was criticized for being alarmist. The cover of the book had this statement. “While you are reading these words four people will have died from starvation. Most of them children.” Ehrlich and his wife, Anne H. Ehrlich, recently revisited the population issue in the Electronic Journal of Sustainable Development and concluded that the message of The Population Bomb is even more important today than it was forty-five years ago. “Perhaps the most serious flaw of The Bomb was that it was much too optimistic about the future,” they wrote.
Their view is that humanity has reached a dangerous turning point in its domination of the planet. We are increasing our numbers and our appetites for our natural resources at the same time. This behavior simply cannot continue.
One of our looming problems is our soil, a vital resource needed to feed our exploding populations. But is the earth’s soil ready for the job?
Part II
WARNING: DANGER AHEAD
5
WARNING SIGN I: THE SOIL
THE RISE OF AGRICULTURE about ten thousand years ago contributed to the historical population growth of man, but along the way we’ve been destroying the very soil we now desperately need to feed our growing population in the future. To get some perspective on this problem, I visited a number of spots aroun
d the world, including Rothamsted Research, the longest-running agricultural research station in the world. The institute, founded in 1843, is in the town of Harpenden in southeastern England, about thirty miles north of London, once dominated by stands of lindens mixed with oak and hazel. This land was transformed into grasslands around 4500 BC when immigrants crossed the English Channel and brought in domestic crops and animals.
I stepped off the train as clouds were receding in the sky. The village was flush with bright-green grasses, roughened sidewalks, and colorful ornamental flowers stippled with the early morning rain. Small agricultural fields surround the hedge-bordered town. I walked several blocks to the facility where I hoped to learn more about what the history of agriculture had done to the soils on our planet and what we might expect from them in the future.
Rothamsted Manor, solidly built with bricks and old timbers, lies in the middle of three hundred acres of rolling verdant agricultural lands a few blocks from the train station. The manor was first mentioned in historical documents dating back to the early 1200s. Since then it has grown, rooms have been added, and the title has changed hands at least five times.
John Bennet Lawes, entrepreneur and agricultural scientist, assumed responsibility for the management of Rothamsted Estate in 1834 after leaving Brasenose College, Oxford. He started a number of agricultural experiments indoors and in the field. Justus von Liebig, a German chemist, taught him how to take bone and boil, grind, and treat it with acid to make fertilizer. Lawes was soon selling “superphosphate” made of powdered phosphate rock treated with sulfuric acid to all the locals. Superphosphate was a super success.
In 1843 he started a fertilizer factory in London, got married, and appointed Joseph Henry Gilbert to manage the field experiments—the official start of the Rothamsted Experimental Station (later Rothamsted Research).
The Next Species: The Future of Evolution in the Aftermath of Man Page 7