How㢂¬„¢s the Day Treating You? Your Teller Wants to Know

(This essay was a finalist for a 2013 National Magazine Award in the Essay category.)

THE PROBLEM WITH environmentalists, Lynn Margulis used to say, is that they retrieve conservation has something to do with biological reality. A researcher who specialized in cells and microorganisms, Margulis was ane of the most important biologists in the last half century—she literally helped to reorder the tree of life, disarming her colleagues that it did not consist of two kingdoms (plants and animals), but v or even six (plants, animals, fungi, protists, and ii types of bacteria).

Until Margulis's death terminal year, she lived in my town, and I would crash-land into her on the street from time to fourth dimension. She knew I was interested in ecology, and she liked to needle me. Hey, Charles, she would call out, are you still all worked up about protecting endangered species?

Margulis was no apologist for unthinking destruction. Withal, she couldn't assistance regarding conservationists' preoccupation with the fate of birds, mammals, and plants as evidence of their ignorance almost the greatest source of evolutionary creativity: the microworld of bacteria, fungi, and protists. More than 90 percent of the living thing on globe consists of microorganisms and viruses, she liked to point out. Heck, the number of bacterial cells in our body is x times more than the number of human being cells!

Bacteria and protists can do things undreamed of by clumsy mammals like us: course giant supercolonies, reproduce either asexually or by swapping genes with others, routinely comprise DNA from entirely unrelated species, merge into symbiotic beings—the list is as endless equally it is amazing. Microorganisms take changed the face up of the earth, crumbling stone and even giving rise to the oxygen we breathe. Compared to this power and diversity, Margulis liked to tell me, pandas and polar bears were biological epiphenomena—interesting and fun, maybe, only not actually meaning.

Does that apply to homo beings, too? I once asked her, feeling similar someone whining to Copernicus about why he couldn't motion the globe a picayune closer to the center of the universe. Aren't nosotros special at all?

This was but chitchat on the street, then I didn't write annihilation downwards. But as I remember it, she answered that Man sapiens really might be interesting—for a mammal, anyway. For one thing, she said, we're unusually successful.

Seeing my face brighten, she added: Of course, the fate of every successful species is to wipe itself out.

OF LICE AND MEN

Why and how did humankind become "unusually successful"? And what, to an evolutionary biologist, does "success" mean, if self-destruction is function of the definition? Does that cocky-destruction include the rest of the biosphere? What are human being beings in the grand scheme of things anyway, and where are nosotros headed? What is human nature, if there is such a matter, and how did we learn it? What does that nature portend for our interactions with the environment? With vii billion of us crowding the planet, information technology'south hard to imagine more vital questions.

1 way to begin answering them came to Mark Stoneking in 1999, when he received a notice from his son'due south school warning of a potential lice outbreak in the classroom. Stoneking is a researcher at the Max Planck Establish for Evolutionary Biological science in Leipzig, Frg. He didn't know much about lice. As a biologist, it was natural for him to noodle effectually for information about them. The most common louse found on human bodies, he discovered, is Pediculus humanus. P. humanus has 2 subspecies: P. humanus capitis—head lice, which feed and live on the scalp—and P. humanus corporis—body lice, which feed on skin but live in clothing. In fact, Stoneking learned, body lice are and then dependent on the protection of vesture that they cannot survive more than a few hours away from it.

It occurred to him that the two louse subspecies could be used as an evolutionary probe. P. humanus capitis, the head louse, could be an ancient annoyance, because human beings take always had hair for it to infest. But P. humanus corporis, the body louse, must non be particularly old, because its need for habiliment meant that information technology could not accept existed while humans went naked. Humankind'due south great coverup had created a new ecological niche, and some head lice had rushed to fill up it. Development then worked its magic; a new subspecies, P. humanus corporis, arose. Stoneking couldn't be sure that this scenario had taken place, though it seemed likely. But if his thought were right, discovering when the torso louse diverged from the caput louse would provide a rough date for when people showtime invented and wore clothing.

The discipline was anything but frivolous: donning a garment is a complicated human action. Article of clothing has practical uses—warming the torso in cold places, shielding it from the dominicus in hot places—but it also transforms the appearance of the wearer, something that has proven to be of inescapable involvement to Homo sapiens. Article of clothing is ornament and emblem; it separates human being beings from their earlier, un-self-conscious land. (Animals run, swim, and fly without article of clothing, but only people tin be naked.) The invention of vesture was a sign that a mental shift had occurred. The human earth had become a realm of complex, symbolic artifacts.

With two colleagues, Stoneking measured the divergence between snippets of DNA in the two louse subspecies. Because DNA is thought to selection up small, random mutations at a roughly constant rate, scientists utilize the number of differences between two populations to tell how long ago they diverged from a common ancestor—the greater the number of differences, the longer the separation. In this case, the body louse had separated from the head louse well-nigh 70,000 years ago. Which meant, Stoneking hypothesized, that vesture as well dated from about lxx,000 years ago.

And not just clothing. As scientists have established, a host of remarkable things occurred to our species at about that time. It marked a dividing line in our history, 1 that fabricated us who nosotros are, and pointed us, for better and worse, toward the globe nosotros now take created for ourselves.

Homo sapiens emerged on the planet nearly 200,000 years ago, researchers believe. From the start, our species looked much as it does today. If some of those long-ago people walked by usa on the street at present, we would recall they looked and acted somewhat oddly, but not that they weren't people. But those anatomically modernistic humans were not, as anthropologists say, behaviorally modern. Those offset people had no language, no clothing, no art, no faith, aught but the simplest, unspecialized tools. They were piffling more advanced, technologically speaking, than their predecessors—or, for that thing, mod chimpanzees. (The large exception was burn, but that was starting time controlled by Homo erectus, one of our ancestors, a million years ago or more.) Our species had then little chapters for innovation that archaeologists have constitute almost no testify of cultural or social change during our first 100,000 years of existence. Equally important, for almost all that time these early humans were bars to a single, small expanse in the hot, dry out savanna of East Africa (and possibly a second, however smaller expanse in southern Africa).

Just now leap forward 50,000 years. East Africa looks much the same. And then do the humans in it—but all of a sudden they are cartoon and carving images, weaving ropes and baskets, shaping and wielding specialized tools, burying the dead in formal ceremonies, and perhaps worshipping supernatural beings. They are wearing clothes—lice-filled dress, to be certain, but dress withal. Momentously, they are using linguistic communication. And they are dramatically increasing their range. Homo sapiens is exploding across the planet.

What caused this remarkable change? By geologists' standards, 50,000 years is an instant, a finger snap, a rounding fault. Nonetheless, about researchers believe that in that flicker of fourth dimension, favorable mutations swept through our species, transforming anatomically modern humans into behaviorally modernistic humans. The idea is not absurd: in the last 400 years, dog breeders converted village dogs into creatures that act as differently equally foxhounds, border collies, and Labrador retrievers. Fifty millennia, researchers say, is more than enough to brand over a species.

Human being sapiens lacks claws, fangs, or exoskeletal plates. Rather, our unique survival skill is our power to innovate, which originates with our species' singular brain—a three-pound universe of hyperconnected neural tissue, constantly aswirl with schemes and notions. Hence every hypothesized crusade for the transformation of humankind from anatomically modern to behaviorally modern involves a physical amending of the wet greyness affair inside our skulls. One candidate explanation is that in this period people adult hybrid mental abilities by interbreeding with Neanderthals. (Some Neanderthal genes indeed appear to be in our genome, though nobody is yet certain of their office.) Some other putative cause is symbolic language—an invention that may have tapped latent creativity and aggressiveness in our species. A tertiary is that a mutation might take enabled our brains to alternate between spacing out on imaginative bondage of association and focusing our attention narrowly on the physical world around us. The quondam, in this view, allows usa to come up with artistic new strategies to reach a goal, whereas the latter enables u.s.a. to execute the concrete tactics required by those strategies.

Each of these ideas is fervently advocated by some researchers and fervently attacked past others. What is clear is that something fabricated over our species between 100,000 and fifty,000 years ago—and right in the eye of that menstruation was Toba.

CHILDREN OF TOBA

About 75,000 years ago, a huge volcano exploded on the island of Sumatra. The biggest blast for several 1000000 years, the eruption created Lake Toba, the world'southward biggest crater lake, and ejected the equivalent of equally much as 3,000 cubic kilometers of rock, enough to cover the Commune of Columbia in a layer of magma and ash that would reach to the stratosphere. A gigantic plumage spread westward, enveloping south asia in tephra (rock, ash, and grit). Drifts in Pakistan and Republic of india reached equally high as six meters. Smaller tephra beds blanketed the Middle East and East Africa. Great rafts of pumice filled the body of water and drifted nigh to Antarctica.

In the long run, the eruption raised Asian soil fertility. In the short term, it was catastrophic. Dust hid the dominicus for every bit much every bit a decade, plunging the world into a years-long winter accompanied by widespread drought. A vegetation collapse was followed past a collapse in the species that depended on vegetation, followed by a plummet in the species that depended on the species that depended on vegetation. Temperatures may accept remained colder than normal for a yard years. Orangutans, tigers, chimpanzees, cheetahs—all were pushed to the verge of extinction.

At nearly this time, many geneticists believe, Homo sapiens' numbers shrank dramatically, perhaps to a few thousand people—the size of a big urban high school. The clearest evidence of this bottleneck is also its main legacy: humankind's remarkable genetic uniformity. Countless people have viewed the differences between races as worth killing for, merely compared to other primates—even compared to most other mammals—human being beings are almost indistinguishable, genetically speaking. Deoxyribonucleic acid is fabricated from exceedingly long chains of "bases." Typically, about 1 out of every two,000 of these "bases" differs betwixt one person and the side by side. The equivalent figure from 2 E. coli (human gut leaner) might be virtually i out of twenty. The bacteria in our intestines, that is, have a hundredfold more innate variability than their hosts—evidence, researchers say, that our species is descended from a modest group of founders.

Uniformity is hardly the just outcome of a bottleneck. When a species shrinks in number, mutations can spread through the unabridged population with amazing rapidity. Or genetic variants that may accept already been in existence—arrays of genes that confer better planning skills, for case—tin can suddenly become more common, effectively reshaping the species inside a few generations as once-unusual traits become widespread.

Did Toba, as theorists like Richard Dawkins have argued, cause an evolutionary clogging that prepare off the creation of behaviorally modernistic people, perhaps past helping previously rare genes—Neanderthal DNA or an opportune mutation—spread through our species? Or did the volcanic blast only clear away other human being species that had previously blocked H. sapiens' expansion? Or was the volcano irrelevant to the deeper story of human change?

For at present, the answers are the subject of conscientious back-and-forth in refereed journals and heated argument in faculty lounges. All that is clear is that almost the time of Toba, new, behaviorally modern people charged so fast into the tephra that human being footprints appeared in Australia within equally few every bit 10,000 years, perhaps within 4,000 or v,000. Stay-at-domicile Homo sapiens 1.0, a wallflower that would never have interested Lynn Margulis, had been replaced by aggressively expansive Homo sapiens ii.0. Something happened, for better and worse, and we were born.

Ane way to illustrate what this upgrade looked like is to consider Solenopsis invicta, the reddish imported burn down pismire. Geneticists believe that S. invicta originated in northern Argentina, an area with many rivers and frequent floods. The floods wipe out ant nests. Over the millennia, these modest, furiously agile creatures have acquired the power to reply to ascent h2o by coalescing into huge, floating, pullulating assurance—workers on the exterior, queen in the center—that drift to the edge of the overflowing. One time the waters recede, colonies swarm back into previously flooded land so speedily that S. invicta actually can utilise the destruction to increase its range.

In the 1930s, Solenopsis invicta was transported to the United States, probably in send ballast, which often consists of haphazardly loaded soil and gravel. Equally a teenaged bug enthusiast, Edward O. Wilson, the famed biologist, spotted the offset colonies in the port of Mobile, Alabama. He saw some very happy fire ants. From the pismire's point of view, it had been dumped into an empty, recently flooded surface area. South. invicta took off, never looking back.

The initial incursion watched by Wilson was likely merely a few 1000 individuals—a number small enough to suggest that random, clogging-style genetic change played a office in the species' subsequent history in this state. In their Argentine birthplace, fire-emmet colonies constantly fight each other, reducing their numbers and creating space for other types of emmet. In the United States, by contrast, the species forms cooperative supercolonies, linked clusters of nests that can spread for hundreds of miles. Systematically exploiting the mural, these supercolonies monopolize every useful resource, wiping out other ant species forth the way—models of zeal and rapacity. Transformed by take chances and opportunity, new-model Southward. invictus needed simply a few decades to conquer most of the southern U.s.a..

Man sapiens did something similar in the wake of Toba. For hundreds of thousands of years, our species had been restricted to East Africa (and, possibly, a similar area in the south). Now, abruptly, new-model Man sapiens were racing across the continents similar so many imported fire ants. The divergence between humans and fire ants is that fire ants specialize in disturbed habitats. Humans, too, specialize in disturbed habitats—but nosotros practise the disturbing.

THE WORLD IS A PETRI DISH

As a student at the University of Moscow in the 1920s, Georgii Gause spent years trying—and failing—to pulsate up support from the Rockefeller Foundation, so the most prominent funding source for non-American scientists who wished to work in the U.s.. Hoping to dazzle the foundation, Gause decided to perform some not bad experiments and draw the results in his grant application.

Past today'due south standards, his methodology was simplicity itself. Gause placed half a gram of oatmeal in 1 hundred cubic centimeters of water, boiled the results for ten minutes to create a goop, strained the liquid portion of the broth into a container, diluted the mixture by adding water, and then decanted the contents into pocket-size, flat-bottomed test tubes. Into each he dripped five Paramecium caudatum or Stylonychia mytilus, both single-celled protozoans, i species per tube. Each of Gause's test tubes was a pocket ecosystem, a food web with a unmarried node. He stored the tubes in warm places for a week and observed the results. He set down his conclusions in a 163-page book, The Struggle for Existence, published in 1934.

Today The Struggle for Being is recognized as a scientific landmark, one of the first successful marriages of theory and experiment in ecology. But the book was non plenty to get Gause a fellowship; the Rockefeller Foundation turned downwards the twenty-four-year-one-time Soviet educatee as comparatively eminent. Gause could not visit the United States for another twenty years, past which time he had indeed become eminent, but as an antibiotics researcher.

What Gause saw in his test tubes is often depicted in a graph, time on the horizontal axis, the number of protozoa on the vertical. The line on the graph is a distorted bell bend, with its left side twisted and stretched into a kind of flattened S. At kickoff the number of protozoans grows slowly, and the graph line slowly ascends to the right. But and so the line hits an inflection point, and all of a sudden rockets upward—a frenzy of exponential growth. The mad rise continues until the organism begins to run out of nutrient, at which point in that location is a 2d inflection point, and the growth curve levels off again as bacteria begin to die. Somewhen the line descends, and the population falls toward zero.

Years agone I watched Lynn Margulis, one of Gause's successors, demonstrate these conclusions to a form at the University of Massachusetts with a time-lapse video of Proteus vulgaris, a bacterium that lives in the gastrointestinal tract. To humans, she said, P. vulgaris is mainly notable every bit a cause of urinary-tract infections. Left alone, it divides about every xv minutes. Margulis switched on the projector. Onscreen was a pocket-sized, wobbly bubble—P. vulgaris—in a shallow, circular glass container: a petri dish. The class gasped. The cells in the time-lapse video seemed to shiver and boil, doubling in number every few seconds, colonies exploding out until the mass of bacteria filled the screen. In just thirty-half-dozen hours, she said, this unmarried bacterium could embrace the unabridged planet in a pes-deep layer of single-celled ooze. Twelve hours after that, information technology would create a living ball of leaner the size of the earth.

Such a cataclysm never happens, considering competing organisms and lack of resources preclude the overwhelming majority of P. vulgaris from reproducing. This, Margulis said, is natural selection, Darwin's keen insight. All living creatures take the same purpose: to brand more of themselves, ensuring their biological future by the just means available. Natural selection stands in the way of this goal. It prunes back almost all species, restricting their numbers and confining their range. In the homo torso, P. vulgaris is checked by the size of its habitat (portions of the human gut), the limits to its supply of nourishment (food proteins), and other, competing organisms. Thus constrained, its population remains roughly steady.

In the petri dish, by contrast, competition is absent; nutrients and habitat seem limitless, at least at first. The bacterium hits the commencement inflection point and rockets up the left side of the curve, swamping the petri dish in a reproductive frenzy. But then its colonies slam into the 2nd inflection point: the border of the dish. When the dish'southward nutrient supply is wearied, P. vulgaris experiences a miniapocalypse.

By luck or superior adaptation, a few species manage to escape their limits, at to the lowest degree for a while. Nature's success stories, they are like Gause's protozoans; the world is their petri dish. Their populations grow exponentially; they accept over large areas, overwhelming their environment as if no forcefulness opposed them. Then they annihilate themselves, drowning in their own wastes or starving from lack of nutrient.

To someone like Margulis, Human being sapiens looks similar one of these briefly fortunate species.

THE WHIP Mitt

No more than a few hundred people initially migrated from Africa, if geneticists are right. But they emerged into landscapes that by today's standards were as rich as Eden. Cool mountains, tropical wetlands, lush forests—all were teeming with food. Fish in the bounding main, birds in the air, fruit on the trees: breakfast was everywhere. People moved in.

Despite our territorial expansion, though, humans were still only in the initial stages of Gause's oddly shaped curve. Ten one thousand years ago, nearly demographers believe, we numbered barely v 1000000, about one human existence for every hundred square kilometers of the world's land surface. Human sapiens was a scarcely noticeable dusting on the surface of a planet dominated past microbes. Nevertheless, at nearly this time—10,000 years ago, give or take a millennium—humankind finally began to approach the first inflection point. Our species was inventing agriculture.

The wild ancestors of cereal crops like wheat, barley, rice, and sorghum have been function of the homo nutrition for nigh every bit long every bit there have been humans to eat them. (The earliest evidence comes from Mozambique, where researchers constitute tiny bits of 105,000-twelvemonth-old sorghum on aboriginal scrapers and grinders.) In some cases people may have watched over patches of wild grain, returning to them year after year. Yet despite the effort and care the plants were non domesticated. Equally botanists say, wild cereals "shatter"—private grain kernels autumn off as they ripen, scattering grain haphazardly, making it impossible to harvest the plants systematically. But when unknown geniuses discovered naturally mutated grain plants that did non shatter—and purposefully selected, protected, and cultivated them—did true agronomics begin. Planting great expanses of those mutated crops, beginning in southern Turkey, later in half a dozen other places, early farmers created landscapes that, then to speak, waited for hands to harvest them.

Farming converted most of the habitable earth into a petri dish. Foragers manipulated their environment with burn, called-for areas to kill insects and encourage the growth of useful species—plants we liked to consume, plants that attracted the other creatures we liked to eat. Nonetheless, their diets were largely restricted to what nature happened to provide in whatsoever given time and season. Agriculture gave humanity the whip hand. Instead of natural ecosystems with their haphazard mix of species (and so many useless organisms guzzling upward resources!), farms are taut, disciplined communities conceived and dedicated to the maintenance of a unmarried species: u.s.a..

Before agriculture, the Ukraine, American Midwest, and lower Yangzi were barely hospitable food deserts, sparsely inhabited landscapes of insects and grass; they became breadbaskets every bit people scythed away suites of species that used soil and h2o we wanted to dominate and replaced them with wheat, rice, and maize (corn). To one of Margulis's dearest bacteria, a petri dish is a uniform expanse of nutrients, all of which it can seize and consume. For Homo sapiens, agriculture transformed the planet into something similar.

Equally in a time-lapse picture, we divided and multiplied across the newly opened land. It had taken Human sapiens 2.0, behaviorally mod humans, not even l,000 years to reach the farthest corners of the globe. Human sapiens 2.0.A—A for agriculture—took a tenth of that time to conquer the planet.

Equally any biologist would predict, success led to an increment in human numbers. Man sapiens rocketed effectually the elbow of the first inflection point in the seventeenth and eighteenth centuries, when American crops like potatoes, sweet potatoes, and maize were introduced to the residuum of the earth. Traditional Eurasian and African cereals—wheat, rice, millet, and sorghum, for example—produce their grain atop thin stalks. Bones physics suggests that plants with this design will fatally topple if the grain gets likewise heavy, which means that farmers can really exist punished if they take an extra-bounteous harvest. By contrast, potatoes and sweetness potatoes grow underground, which means that yields are not express past the plant's compages. Wheat farmers in Edinburgh and rice farmers in Edo akin discovered they could harvest iv times as much dry food matter from an acre of tubers than they could from an acre of cereals. Maize, also, was a winner. Compared to other cereals, it has an extra-thick stalk and a unlike, more productive type of photosynthesis. Taken together, these immigrant crops vastly increased the food supply in Europe, Asia, and Africa, which in plough helped increase the supply of Europeans, Asians, and Africans. The population boom had begun.

Numbers kept rising in the nineteenth and twentieth centuries, after a High german chemist, Justus von Liebig, discovered that constitute growth was express past the supply of nitrogen. Without nitrogen, neither plants nor the mammals that swallow plants tin create proteins, or for that matter the DNA and RNA that direct their product. Pure nitrogen gas (N2) is plentiful in the air merely plants are unable to blot it, because the two nitrogen atoms in N2 are welded and then tightly together that plants cannot carve up them apart for utilise. Instead, plants accept in nitrogen only when it is combined with hydrogen, oxygen, and other elements. To restore wearied soil, traditional farmers grew peas, beans, lentils, and other pulses. (They never knew why these "light-green manures" replenished the country. Today we know that their roots contain special bacteria that convert useless N2 into "bio-available" nitrogen compounds.) After Liebig, European and American growers replaced those crops with high-intensity fertilizer—nitrogen-rich guano from Peru at first, and then nitrates from mines in Chile. Yields soared. Merely supplies were much more limited than farmers liked. So intense was the competition for fertilizer that a guano state of war erupted in 1879, engulfing much of western South America. Near three,000 people died.

Two more German language chemists, Fritz Haber and Carl Bosch, came to the rescue, discovering the key steps to making synthetic fertilizer from fossil fuels. (The procedure involves combining nitrogen gas and hydrogen from natural gas into ammonia, which is then used to create nitrogenous compounds usable past plants.) Haber and Bosch are not nearly as well known every bit they should be; their discovery, the Haber-Bosch procedure, has literally changed the chemical composition of the globe, a feat previously reserved for microorganisms. Farmers have injected then much synthetic fertilizer into the soil that soil and groundwater nitrogen levels have risen worldwide. Today, roughly a third of all the protein (fauna and vegetable) consumed by humankind is derived from synthetic nitrogen fertilizer. Another way of putting this is to say that Haber and Bosch enabled Homo sapiens to extract about 2 billion people's worth of food from the same amount of available state.

The improved wheat, rice, and (to a bottom extent) maize varieties developed by found breeders in the 1950s and 1960s are ofttimes said to have prevented another billion deaths. Antibiotics, vaccines, and water-treatment plants too saved lives by pushing back humankind's bacterial, viral, and fungal enemies. With nearly no surviving biological competition, humankind had ever more than unhindered access to the planetary petri dish: in the past two hundred years, the number of humans walking the planet ballooned from ane to vii billion, with a few billion more than expected in coming decades.

Rocketing up the growth curve, human beings "at present appropriate nearly 40% . . . of potential terrestrial productivity." This figure dates from 1986—a famous estimate by a team of Stanford biologists. X years after, a second Stanford team calculated that the "fraction of the country'south biological product that is used or dominated" by our species had risen to as much as 50 percentage. In 2000, the chemist Paul Crutzen gave a name to our time: the "Anthropocene," the era in which Homo sapiens became a force operating on a planetary calibration. That year, half of the world's accessible fresh h2o was consumed by human beings.

Lynn Margulis, information technology seems prophylactic to say, would accept scoffed at these assessments of man domination over the natural world, which, in every instance I know of, practice non take into business relationship the enormous affect of the microworld. But she would non accept disputed the central idea: Human sapiens has get a successful species, and is growing accordingly.

If we follow Gause's pattern, growth will continue at a febrile speed until nosotros hit the 2d inflection point. At that time nosotros will take wearied the resource of the global petri dish, or finer made the atmosphere toxic with our carbon-dioxide waste product, or both. Afterwards that, man life will be, briefly, a Hobbesian nightmare, the living overwhelmed past the dead. When the rex falls, and so exercise his minions; information technology is possible that our fall might also take down most mammals and many plants. Possibly sooner, quite probable later, in this scenario, the world will again be a choir of bacteria, fungi, and insects, as it has been through most of its history.

Information technology would be foolish to expect anything else, Margulis thought. More than that, it would be unnatural.

AS PLASTIC Equally CANBY

In The Phantom Tollbooth, Norton Juster's archetype, pun-filled adventure tale, the young Milo and his faithful companions unexpectedly discover themselves transported to a dour, mysterious island. Encountering a human in a tweed jacket and beanie, Milo asks him where they are. The man replies by request if they know who he is—the human being is, apparently, confused on the field of study. Milo and his friends confer, then inquire if he tin can describe himself.

"Yes, indeed," the human replied happily. "I'm as tall equally can exist"—and he grew straight upwards until all that could exist seen of him were his shoes and stockings—"and I'm equally short equally can be"—and he shrank down to the size of a pebble. "I'm as generous as can be," he said, handing each of them a large red apple, "and I'm every bit selfish equally can exist," he snarled, grabbing them back over again.

In short order, the companions acquire that the man is every bit strong every bit tin be, weak every bit tin exist, smart every bit can be, stupid every bit can be, graceful every bit can be, clumsy every bit—you get the picture show. "Is that any help to yous?" he asks. Again, Milo and his friends confer, and realize that the answer is actually quite simple:

"Without a doubt," Milo ended brightly, "y'all must exist Canby."

"Of form, yes, of course," the man shouted. "Why didn't I recollect of that? I'm as happy as can be."

With Canby, Juster presumably meant to mock a certain kind of babyish, uncommitted man-child. But I can't help thinking of poor sometime Canby as exemplifying one of humankind'south greatest attributes: behavioral plasticity. The term was coined in 1890 by the pioneering psychologist William James, who divers information technology every bit "the possession of a structure weak plenty to yield to an influence, just strong enough not to yield all at in one case." Behavioral plasticity, a defining feature of Homo sapiens' big brain, means that humans tin change their habits; most as a matter of course, people change careers, quit smoking or take upwards vegetarianism, convert to new religions, and migrate to distant lands where they must larn foreign languages. This plasticity, this Canby-hood, is the authentication of our transformation from anatomically modernistic Human being sapiens to behaviorally modern Homo sapiens—and the reason, perhaps, we were able to survive when Toba reconfigured the landscape.

Other creatures are much less flexible. Like flat-dwelling cats that compulsively hide in the closet when visitors go far, they have limited capacity to welcome new phenomena and change in response. Homo beings, by contrast, are so exceptionally plastic that vast swaths of neuroscience are devoted to trying to explain how this could come up about. (Nobody knows for certain, but some researchers now call back that detail genes give their possessors a heightened, inborn awareness of their environs, which tin pb both to useless, neurotic sensitivity and greater ability to find and adjust to new situations.)

Plasticity in individuals is mirrored by plasticity on a societal level. The caste system in social species like honeybees is elaborate and finely tuned merely fixed, as if in amber, in the loops of their DNA. Some leafcutter ants are said to accept, next to human beings, the biggest and nearly complex societies on earth, with elaborately coded behavior that reaches from disposal of the dead to circuitous agronomical systems. Housing millions of individuals in inconceivably ramose subterranean networks, leafcutter colonies are "Earth's ultimate superorganisms," Edward O. Wilson has written. Only they are incapable of fundamental change. The centrality and authority of the queen cannot be challenged; the tiny minority of males, used only to inseminate queens, volition never larn new responsibilities.

Human societies are far more than varied than their insect cousins, of course. But the true deviation is their plasticity. It is why humankind, a species of Canbys, has been able to motility into every corner of the globe, and to control what we find in that location. Our ability to modify ourselves to excerpt resource from our surroundings with e'er-increasing efficiency is what has made Homo sapiens a successful species. It is our greatest blessing.

Or was our greatest blessing, anyway.

DISCOUNT RATES

Past 2050, demographers predict, as many as 10 billion human beings will walk the earth, 3 billion more than today. Not but will more than people exist than ever before, they will be richer than ever before. In the terminal three decades hundreds of millions in Red china, India, and other formerly poor places have lifted themselves from destitution—arguably the almost important, and certainly the most heartening, accomplishment of our time. Even so, similar all human being enterprises, this great success will pose bully difficulties.

In the past, ascension incomes take invariably prompted rising need for goods and services. Billions more jobs, homes, cars, fancy electronics—these are things the newly prosperous volition want. (Why shouldn't they?) But the greatest challenge may be the nigh bones of all: feeding these extra mouths. To agronomists, the prospect is sobering. The newly flush volition not want their ancestors' gruel. Instead they will ask for pork and beefiness and lamb. Salmon will sizzle on their outdoor grills. In wintertime, they will desire strawberries, like people in New York and London, and clean bibb lettuce from hydroponic gardens.

All of these, each and every one, require vastly more resources to produce than elementary peasant agronomics. Already 35 per centum of the earth's grain harvest is used to feed livestock. The process is terribly inefficient: between seven and ten kilograms of grain are required to produce one kilogram of beef. Not only volition the globe's farmers have to produce enough wheat and maize to feed 3 billion more people, they will have to produce enough to give them all hamburgers and steaks. Given present patterns of food consumption, economists believe, we volition need to produce about xl percentage more grain in 2050 than we exercise today.

How can we provide these things for all these new people? That is just part of the question. The full question is: How can nosotros provide them without wrecking the natural systems on which all depend?

Scientists, activists, and politicians take proposed many solutions, each from a unlike ideological and moral perspective. Some argue that nosotros must drastically throttle industrial civilization. (Stop free energy-intensive, chemical-based farming today! Eliminate fossil fuels to halt climate change!) Others claim that only intense exploitation of scientific noesis can save the states. (Constitute super-productive, genetically modified crops at present! Switch to nuclear power to halt climate change!) No matter which class is chosen, though, information technology will require radical, large-calibration transformations in the human enterprise—a daunting, hideously expensive job.

Worse, the send is as well big to plough quickly. The world'due south food supply cannot exist decoupled chop-chop from industrial agriculture, if that is seen every bit the answer. Aquifers cannot exist recharged with a snap of the fingers. If the high-tech route is chosen, genetically modified crops cannot be bred and tested overnight. Similarly, carbon-sequestration techniques and nuclear power plants cannot be deployed instantly. Changes must be planned and executed decades in advance of the usual signals of crisis, but that's similar asking salubrious, happy sixteen-year-olds to write living wills.

Not only is the job daunting, it'south strange. In the name of nature, nosotros are asking human beings to practice something securely unnatural, something no other species has ever done or could ever do: constrain its own growth (at least in some ways). Zebra mussels in the Dandy Lakes, brown tree snakes in Guam, water hyacinth in African rivers, gypsy moths in the northeastern U.S., rabbits in Australia, Burmese pythons in Florida—all these successful species have overrun their environments, heedlessly wiping out other creatures. Similar Gause's protozoans, they are racing to notice the edges of their petri dish. Non 1 has voluntarily turned back. Now we are request Homo sapiens to argue itself in.

What a peculiar thing to enquire! Economists like to talk about the "discount rate," which is their term for preferring a bird in hand today over two in the bush tomorrow. The term sums upwards function of our human being nature equally well. Evolving in small, constantly moving bands, we are as hard-wired to focus on the immediate and local over the long-term and faraway as we are to prefer parklike savannas to deep dark forests. Thus, we care more about the broken stoplight upwardly the street today than conditions next yr in Republic of croatia, Cambodia, or the Congo. Rightly and then, evolutionists bespeak out: Americans are far more probable to be killed at that stoplight today than in the Congo next twelvemonth. Nevertheless here we are asking governments to focus on potential planetary boundaries that may not exist reached for decades. Given the discount rate, nothing could be more understandable than the U.S. Congress'due south failure to grapple with, say, climate change. From this perspective, is in that location any reason to imagine that Human being sapiens, unlike mussels, snakes, and moths, can exempt itself from the natural fate of all successful species?

To biologists similar Margulis, who spend their careers arguing that humans are merely part of the natural order, the reply should be clear. All life is similar at base. All species seek without intermission to make more of themselves—that is their goal. Past multiplying till we achieve our maximum possible numbers, even as we take out much of the planet, we are fulfilling our destiny.

From this vantage, the respond to the question whether we are doomed to destroy ourselves is yes. It should be obvious.

Should be—but perhaps is not.

HARA HACHI BU

When I imagine the profound social transformation necessary to avoid calamity, I think near Robinson Crusoe, hero of Daniel Defoe's famous novel. Defoe clearly intended his hero to be an exemplary man. Shipwrecked on an uninhabited island off Venezuela in 1659, Crusoe is an impressive instance of behavioral plasticity. During his 20-vii-year exile he learns to grab fish, hunt rabbits and turtles, tame and pasture island goats, prune and support local citrus trees, and create "plantations" of barley and rice from seeds that he salvaged from the wreck. (Defoe apparently didn't know that citrus and goats were not native to the Americas and thus Crusoe probably wouldn't accept found them in that location.) Rescue comes at last in the form of a shipful of ragged mutineers, who plan to maroon their captain on the supposedly empty island. Crusoe helps the captain recapture his ship and offers the defeated mutineers a option: trial in England or permanent banishment to the island. All choose the latter. Crusoe has harnessed so much of the island's productive power to human apply that even a gaggle of inept seamen tin survive at that place in comfort.

To get Crusoe on his unlucky voyage, Defoe made him an officeholder on a slave ship, transporting captured Africans to South America. Today, no author would make a slave seller the admirable hero of a novel. But in 1720, when Defoe published Robinson Crusoe, no readers said boo about Crusoe'south occupation, because slavery was the norm from one end of the world to some other. Rules and names differed from place to place, but coerced labor was everywhere, building roads, serving aristocrats, and fighting wars. Slaves teemed in the Ottoman Empire, Mughal India, and Ming China. Unfree hands were less common in continental Europe, but Portugal, Spain, France, England, and the netherlands happily exploited slaves by the meg in their American colonies. Few protests were heard; slavery had been role of the cloth of life since the code of Hammurabi.

And then, in the space of a few decades in the nineteenth century, slavery, one of humankind'southward most enduring institutions, most vanished.

The sheer implausibility of this change is staggering. In 1860, slaves were, collectively, the single most valuable economic asset in the Usa, worth an estimated $3 billion, a vast sum in those days (and most $10 trillion in today's money). Rather than investing in factories like northern entrepreneurs, southern businessmen had sunk their uppercase into slaves. And from their perspective, correctly so—masses of enchained men and women had made the region politically powerful, and gave social condition to an entire class of poor whites. Slavery was the foundation of the social order. Information technology was, thundered John C. Calhoun, a one-time senator, secretary of state, and vice president, "instead of an evil, a good—a positive good." Yet just a few years afterward Calhoun spoke, part of the U.s. set out to destroy this establishment, wrecking much of the national economic system and killing half a 1000000 citizens forth the mode.

Incredibly, the turn against slavery was equally universal equally slavery itself. Great United kingdom of great britain and northern ireland, the globe's biggest human trafficker, closed down its slave operations in 1808, though they were amid the nation'due south most profitable industries. The Netherlands, French republic, Spain, and Portugal soon followed. Like stars winking out at the approach of dawn, cultures across the globe removed themselves from the previously universal exchange of human cargo. Slavery notwithstanding exists hither and there, but in no society anywhere is information technology formally accepted as role of the social cloth.

Historians have provided many reasons for this extraordinary transition. But one of the most important is that abolitionists had convinced huge numbers of ordinary people around the earth that slavery was a moral disaster. An institution central to homo guild for millennia was swiftly dismantled by ideas and a telephone call to action, loudly repeated.

In the last few centuries, such profound changes have occurred repeatedly. Since the beginning of our species, for case, every known gild has been based on the domination of women past men. (Rumors of past matriarchal societies abound, but few archaeologists believe them.) In the long view, women's lack of liberty has been as cardinal to the human being enterprise as gravitation is to the celestial guild. The degree of suppression varied from fourth dimension to time and place to place, but women never had an equal voice; indeed, some show exists that the penalty for possession of two X chromosomes increased with technological progress. Even every bit the industrial Northward and agricultural South warred over the treatment of Africans, they regarded women identically: in neither half of the nation could they attend higher, have a bank account, or own belongings. Every bit confining were women'south lives in Europe, Asia, and Africa. Nowadays women are the majority of U.S. college students, the majority of the workforce, and the bulk of voters. Again, historians assign multiple causes to this shift in the human status, rapid in time, staggering in scope. Only one of the most important was the power of ideas—the voices, deportment, and examples of suffragists, who through decades of ridicule and harassment pressed their case. In contempo years something similar seems to accept occurred with gay rights: first a few lonely advocates, censured and mocked; and then victories in the social and legal sphere; finally, mayhap, a deadening motility to equality.

Less well known, just equally profound: the decline in violence. Foraging societies waged war less brutally than industrial societies, but more than frequently. Typically, archaeologists believe, well-nigh a quarter of all hunters and gatherers were killed past their fellows. Violence declined somewhat as humans gathered themselves into states and empires, but was however a abiding presence. When Athens was at its tiptop in the 4th and 5th centuries BC, it was ever at war: against Sparta (Commencement and Second Peloponnesian Wars, Corinthian War); against Persia (Greco-Persian Wars, Wars of the Delian League); against Aegina (Aeginetan War); against Macedon (Olynthian State of war); against Samos (Samian War); against Chios, Rhodes, and Cos (Social War).

In this respect, classical Greece was nothing special—look at the ghastly histories of China, sub-Saharan Africa, or Mesoamerica. Similarly, early modern Europe's wars were so fast and furious that historians simply assemble them into catchall titles like the Hundred Years' War, followed by the shorter merely fifty-fifty more destructive 30 Years' War. And fifty-fifty every bit Europeans and their descendants paved the manner toward today's concept of universal man rights past creating documents like the Beak of Rights and the Announcement of the Rights of Homo and of the Citizen, Europe remained so mired in combat that information technology fought two conflicts of such massive scale and reach they became known equally "world" wars.

Since the 2d World War, however, rates of violent death have fallen to the lowest levels in known history. Today, the average person is far less likely to be slain past another member of the species than ever earlier—an extraordinary transformation that has occurred, well-nigh unheralded, in the lifetime of many of the people reading this commodity. Every bit the political scientist Joshua Goldstein has written, "we are winning the state of war on war." Again, in that location are multiple causes. But Goldstein, probably the leading scholar in this field, argues that the most of import is the emergence of the Un and other transnational bodies, an expression of the ideas of peace activists before in the last century.

As a relatively immature species, we accept an adolescent propensity to make a mess: we pollute the air we breathe and the h2o nosotros drink, and announced stalled in an age of carbon dumping and nuclear experimentation that is putting countless species at take chances including our ain. But we are making undeniable progress nonetheless. No European in 1800 could take imagined that in 2000 Europe would accept no legal slavery, women would be able to vote, and gay people would be able to marry. No i could have guessed a continent that had been violent itself apart for centuries would exist free of armed conflict, fifty-fifty among terrible economic times. Given this tape, even Lynn Margulis might break (perchance).

Preventing Human being sapiens from destroying itself à la Gause would require a notwithstanding greater transformation—behavioral plasticity of the highest gild—because we would exist pushing against biological nature itself. The Japanese have an expression, hara hachi bu, which means, roughly speaking, "abdomen 80 percent full." Hara hachi bu is shorthand for an ancient injunction to cease eating before feeling full. Nutritionally, the control makes a great deal of sense. When people eat, their stomachs produce peptides that bespeak fullness to the nervous organization. Unfortunately, the machinery is then ho-hum that eaters frequently perceive satiety just subsequently they have consumed too much—hence the all-as well-common condition of feeling bloated or sick from overeating. Nippon—actually, the Japanese island of Okinawa—is the simply place on earth where large numbers of people are known to restrict their ain calorie intake systematically and routinely. Some researchers claim that hara hachi bu is responsible for Okinawans' notoriously long life spans. But I think of information technology as a metaphor for stopping before the second inflection betoken, voluntarily forswearing short-term consumption to obtain a long-term benefit.

Evolutionarily speaking, a species-broad adoption of hara hachi bu would exist unprecedented. Thinking about it, I can flick Lynn Margulis rolling her eyes. But is it so unlikely that our species, Canbys i and all, would be able to do exactly that earlier nosotros round that fateful bend of the second inflection point and nature does information technology for us?

I can imagine Margulis's response: You're imagining our species as some sort of big-brained, hyperrational, do good-price-computing calculator! A better analogy is the leaner at our feet! Still, Margulis would be the first to agree that removing the shackles from women and slaves has begun to unleash the suppressed talents of two-thirds of the human being race. Drastically reducing violence has prevented the waste of countless lives and staggering amounts of resources. Is it really impossible to believe that we wouldn't use those talents and those resources to draw back before the completeness?

Our record of success is not that long. In any case, by successes are no guarantee of the future. But information technology is terrible to suppose that we could get so many other things right and get this one wrong. To have the imagination to encounter our potential stop, but non have the imagination to avoid it. To send humankind to the moon but neglect to pay attending to the earth. To have the potential only to exist unable to use it—to be, in the end, no different from the protozoa in the petri dish. It would be evidence that Lynn Margulis'due south most dismissive beliefs had been right subsequently all. For all our speed and voraciousness, our changeable sparkle and wink, we would be, at last count, not an peculiarly interesting species. O

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Source: https://orionmagazine.org/article/state-of-the-species/

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