A Short History of Nearly Everything: Special Illustrated Edition

by Bill Bryson

  If creatures as intimately associated with us as bed mites escaped our notice until the age of colour television, it’s hardly surprising that most of the rest of the small-scale world is barely known to us. Go out into the woods—any woods at all—bend down and scoop up a handful of soil, and you will be holding up to ten billion bacteria, most of them unknown to science. Your sample will also contain perhaps a million plump yeasts, some two hundred thousand hairy little fungi known as moulds, perhaps ten thousand protozoans (of which the most familiar is the amoeba) and assorted rotifers, flatworms, roundworms and other microscopic creatures known collectively as cryptozoa. A large portion of these will also be unknown.

  The most comprehensive handbook of micro-organisms, Bergey’s Manual of Systematic Bacteriology, lists about four thousand types of bacteria. In the 1980s, a pair of Norwegian scientists, Jostein Goksøyr and Vigdis Torsvik, collected a gram of random soil from a beech forest near their lab in Bergen and carefully analysed its bacterial content. They found that this single small sample contained between four thousand and five thousand separate bacterial species, more than in the whole of Bergey’s Manual. They then travelled to a coastal location a few miles away, scooped up another gram of earth and found that it contained four to five thousand other species. As Edward O. Wilson observes: “If over 9,000 microbial types exist in two pinches of substrate from two localities in Norway, how many more await discovery in other, radically different habitats?” Well, according to one estimate, it could be as many as 400 million.

  We don’t look in the right places. In The Diversity of Life, Wilson describes how one botanist spent a few days tramping around 10 hectares of jungle in Borneo and discovered a thousand new species of flowering plant—more than are found in the whole of North America. The plants weren’t hard to find. It’s just that no-one had looked there before. Koen Maes of the Kenyan National Museum told me that he went to one cloud forest, as mountaintop forests are known in Kenya, and in half an hour “of not particularly dedicated looking” found four new species of millipedes, three representing new genera, and one new species of tree. “Big tree,” he added, and shaped his arms as if about to dance with a very large partner. Cloud forests are found on the tops of plateaux and have sometimes been isolated for millions of years. “They provide the ideal climate for biology and they have hardly been studied,” he said.

  Overall, tropical rainforests cover only about 6 per cent of Earth’s surface, but they harbour more than half of its animal life and about two-thirds of its flowering plants—and most of this life remains unknown to us because too few researchers spend time in them. Not incidentally, much of this could be quite valuable. At least 99 per cent of flowering plants have never been tested for their medicinal properties. Because they can’t flee from predators, plants have had to contrive elaborate chemical defences, and so are particularly rich in intriguing compounds. Even now, nearly a quarter of all prescribed medicines are derived from just forty plants, with another 16 per cent coming from animals or microbes, so there is a serious risk with every hectare of forest felled of losing medically vital possibilities. Using a method called combinatorial chemistry, chemists can generate 40,000 compounds at a time in labs, but these products are random and not uncommonly useless, whereas any natural molecule will have already passed what The Economist calls “the ultimate screening programme: over three and a half billion years of evolution.”

  Looking for the unknown isn’t simply a matter of travelling to remote or distant places, however. In his book Life: An Unauthorised Biography, Richard Fortey notes how one ancient bacterium was found on the wall of a country pub “where men had urinated for generations”—a discovery that would seem to involve rare amounts of luck and devotion and possibly some other quality not specified.

  There aren’t enough specialists. The stock of things to be found, examined and recorded very much outruns the supply of scientists available to do it. Take the hardy and little-known organisms known as bdelloid rotifers. These are microscopic animals that can survive almost anything.

  When conditions are tough, they curl up into a compact shape, switch off their metabolism and wait for better times. In this state, you can drop them into boiling water or freeze them almost to absolute zero—that is, the level where even atoms give up—and, when this torment has finished and they are returned to a more pleasing environment, they will uncurl and move on as if nothing has happened. So far, about 500 species have been identified (though other sources say 360), but nobody has any idea, even remotely, how many there may be altogether. For years almost all that was known about them was thanks to the work of a devoted amateur, a London clerical worker named David Bryce who studied them in his spare time. They can be found all over the world, but you could have all the bdelloid rotifer experts in the world to dinner and not have to borrow plates from the neighbours.

  A bdelloid rotifer, a simple roundworm, magnified about 370 times. No one knows how many types of bdelloid rotifers there may be in the world as they are so little studied. (Credit 23.12)

  Even creatures as important and ubiquitous as fungi (and fungi are both) attract comparatively little notice. Fungi are everywhere and come in many forms—as mushrooms, moulds, mildews, yeasts and puffballs, to name but a sampling—and they exist in volumes that most of us little suspect. Gather together all the fungi found in a typical hectare of meadowland and you would have 2,800 kilograms of the stuff. These are not marginal organisms. Without fungi there would be no potato blights, Dutch elm disease, jock itch or athlete’s foot, but also no yogurts or beers or cheeses. Altogether about seventy thousand species of fungi have been identified, but it is thought the total number could be as high as 1.8 million. A lot of mycologists work in industry, making cheeses and yogurts and the like, so it is hard to say how many are actively involved in research, but we can safely take it that there are more species of fungi to be found than there are people to find them.

  The world is a really big place. We have been gulled by the ease of air travel and other forms of communication into thinking that the world is not all that big, but at ground level, where researchers must work, it is actually enormous—enormous enough to be full of surprises. The okapi, the nearest living relative of the giraffe, is now known to exist in substantial numbers in the rainforests of Zaire—the total population is estimated at perhaps thirty thousand—yet its existence wasn’t even suspected until the twentieth century. The large, flightless New Zealand bird called the takahe had been presumed extinct for two hundred years before being found living in a rugged area of the country’s South Island. In 1995 a team of French and British scientists in Tibet, who were lost in a snowstorm in a remote valley, came across a breed of horse, called the Riwoche, that had previously been known only from prehistoric cave drawings. The valley’s inhabitants were astonished to learn that the horse was considered a rarity in the wider world.

  The takahe, a flightless bird from New Zealand that was thought to have been extinct for about 200 years. The tireless searching of a Dr. Geoffrey Orbell resulted in the discovery in 1948 of about 250 takahe in the remote Murchison Mountains of New Zealand’s fjordland. The takahe remains rare and endangered. (Credit 23.13)

  Some people think even greater surprises may await us. “A leading British ethno-biologist,” wrote The Economist in 1995, “thinks a megatherium, a sort of giant ground sloth which may stand as high as a giraffe…may lurk in the fastnesses of the Amazon basin.” Perhaps significantly, the ethno-biologist wasn’t named; perhaps even more significantly, nothing more has been heard of him or his giant sloth. No-one, however, can categorically say that no such thing is there until every jungly glade has been investigated, and we are a long way from achieving that.

  But even if we groomed thousands of fieldworkers and dispatched them to the furthest corners of the world, it would not be effort enough, for wherever life can be, it is. Life’s extraordinary fecundity is amazing, even gratifying, but also problematic. To survey it all, yo
u would have to turn over every rock, sift through the litter on every forest floor, sieve unimaginable quantities of sand and dirt, climb into every forest canopy and devise much more efficient ways to examine the seas. Even then you would overlook whole ecosystems. In the 1980s, amateur cave explorers entered a deep cave in Romania that had been sealed off from the outside world for a long but unknown period and found thirty-three species of insects and other small creatures—spiders, centipedes, lice—all blind, colourless and new to science. They were living off the microbes in the surface scum of pools, which in turn were feeding on hydrogen sulphide from hot springs.

  A page from Studies on the Variation, Distribution and Evolution of the Genus Partula, by Henry Edward Crampton, who spent an astonishing fifty years recording the minutest details of one genus of Polynesian land snail. (Credit 23.14)

  Our instinct may be to see the impossibility of tracking everything down as frustrating, dispiriting, perhaps even appalling, but it can just as well be viewed as almost unbearably exciting. We live on a planet that has a more or less infinite capacity to surprise. What reasoning person could possibly want it any other way?

  What is nearly always most arresting in any ramble through the scattered disciplines of modern science is realizing how many people have been willing to devote lifetimes to the most sumptuously esoteric lines of enquiry. In one of his essays, Stephen Jay Gould notes how a hero of his named Henry Edward Crampton spent fifty years, from 1906 to his death in 1956, quietly studying a genus of land snails called Partula in Polynesia. Over and over, year after year, Crampton measured to the tiniest degree—to eight decimal places—the whorls and arcs and gentle curves of numberless Partula, compiling the results into fastidiously detailed tables. A single line of text in a Crampton table could represent weeks of measurement and calculation.

  Only slightly less devoted, and certainly more unexpected, was Alfred C. Kinsey, who became famous for his studies of human sexuality in the 1940s and 1950s. Before his mind became filled with sex, so to speak, Kinsey was an entomologist, and a dogged one at that. In one expedition lasting two years, he hiked 4,000 kilometres to assemble a collection of three hundred thousand wasps. How many stings he collected along the way is not, alas, recorded.

  Something that had been puzzling me was the question of how you assured a chain of succession in these arcane fields. Clearly there cannot be many institutions in the world that require or are prepared to support specialists in barnacles or Pacific snails. As we parted at the Natural History Museum in London, I asked Richard Fortey how science ensures that when one person goes there’s someone ready to take his place.

  He chuckled rather heartily at my naivety. “I’m afraid it’s not as if we have substitutes sitting on the bench somewhere waiting to be called in to play. When a specialist retires or, even more unfortunately, dies, that can bring a stop to things in that field, sometimes for a very long while.”

  “And I suppose that’s why you value someone who spends forty-two years studying a single species of plant, even if it doesn’t produce anything terribly new?”

  “Precisely,” he said, “precisely.” And he really seemed to mean it.

  1 To illustrate, humans are in the domain eucarya, in the kingdom animalia, in the phylum chordata, in the subphylum vertebrata, in the class mammalia, in the order primates, in the family hominidae, in the genus Homo, in the species sapiens. (The convention, I’m informed, is to italicize genus and species names, but not those of higher divisions.) Some taxonomists employ further subdivisions: tribe, suborder, infraorder, parvorder and more.

  2 The formal word for a zoological category, such as phylum or genus. The plural is taxa.

  3 We are actually getting worse at some matters of hygiene. Dr. Maunder believes that the move towards low-temperature washing-machine detergents has encouraged bugs to proliferate. As he puts it: “If you wash lousy clothing at low temperatures, all you get is cleaner lice.”

  A miracle of instinct, a male sperm cell penetrates the surface of a female egg in a single-minded quest for fertility. Beneath this permeable outer surface is a solid inner shell that the sperm must penetrate to achieve conception. All being well, within minutes the egg and sperm together will be producing the first of the ten quadrillion cells necessary to make a human life. (Credit 24.1)

  CELLS

  It starts with a single cell. The first cell splits to become two and the two become four and so on. After just forty-seven doublings, you have 10,000 trillion (10,000,000,000,000,000) cells in your body and are ready to spring forth as a human being.1 And every one of those cells knows exactly what to do to preserve and nurture you from the moment of conception to your last breath.

  You have no secrets from your cells. They know far more about you than you do. Each one carries a copy of the complete genetic code—the instruction manual for your body—so it knows how to do not only its own job but every other job in the body too. Never in your life will you have to remind a cell to keep an eye on its adenosine triphosphate levels or to find a place for the extra squirt of folic acid that’s just unexpectedly turned up. It will do that for you, and millions more things besides.

  Every cell in nature is a thing of wonder. Even the simplest are far beyond the limits of human ingenuity. To build the most basic yeast cell, for example, you would have to miniaturize about the same number of components as are found in a Boeing 777 jetliner and fit them into a sphere just 5 microns across; then somehow you would have to persuade that sphere to reproduce.

  But yeast cells are as nothing compared with human cells, which are not just more varied and complicated, but vastly more fascinating because of their complex interactions.

  Your cells are a country of 10,000 trillion citizens, each devoted in some intensively specific way to your overall well-being. There isn’t a thing they don’t do for you. They let you feel pleasure and form thoughts. They enable you to stand and stretch and caper. When you eat, they extract the nutrients, distribute the energy, and carry off the wastes—all those things you learned about in school biology—but they also remember to make you hungry in the first place and reward you with a feeling of well-being afterwards so that you won’t forget to eat again. They keep your hair growing, your ears waxed, your brain quietly purring. They manage every corner of your being. They will jump to your defence the instant you are threatened. They will unhesitatingly die for you—billions of them do so daily. And not once in all your years have you thanked even one of them. So let us take a moment now to regard them with the wonder and appreciation they deserve.

  A graphic illustration of a nerve cell or neuron, showing the cell body with its many extensions—dendrites—which form a network of connections with other nerve cells. These bewilderingly complex interconnections allow for the dynamic transmission and storage of immense amounts of information. (Credit 24.2)

  We understand a little of how cells do the things they do—how they lay down fat or manufacture insulin or engage in many of the other acts necessary to maintain a complicated entity like yourself—but only a little. You have at least 200,000 different types of protein labouring away inside you and so far we understand what no more than about 2 per cent of them do. (Others put the figure at more like 50 per cent; it depends, apparently on what you mean by “understand.”)

  A fertilized egg cell begins the process of division. (Credit 24.2a)

  Surprises at the cellular level turn up all the time. In nature, nitric oxide is a formidable toxin and a common component of air pollution. So scientists were naturally a little surprised when, in the mid-1980s, they found it being produced in a curiously devoted manner in human cells. Its purpose was at first a mystery, but then scientists began to find it all over the place—controlling the flow of blood and the energy levels of cells, attacking cancers and other pathogens, regulating the sense of smell, even assisting in penile erections. It also explained why nitroglycerine, the well-known explosive, soothes the heart pain known as angina. (It is converted i
nto nitric oxide in the bloodstream, relaxing the muscle linings of vessels, allowing blood to flow more freely.) In barely the space of a decade this one gassy substance went from extraneous toxin to ubiquitous elixir.

  You possess “some few hundred” different types of cell, according to the Belgian biochemist Christian de Duve, and they vary enormously in size and shape, from nerve cells whose filaments can stretch to over a metre to tiny, disc-shaped red blood cells to the rod-shaped photocells that help to give us vision. They also come in a sumptuously wide range of sizes—nowhere more strikingly than at the moment of conception, when a single beating sperm confronts an egg 85,000 times bigger than it (which rather puts the notion of male conquest into perspective). On average, however, a human cell is about 20 microns wide—that is, about two-hundredths of a millimetre—which is too small to be seen but roomy enough to hold thousands of complicated structures like mitochondria, and millions upon millions of molecules. In the most literal way, cells also vary in liveliness. Your skin cells are all dead. It’s a somewhat galling notion to reflect that every inch of your surface is deceased. If you are an average-sized adult you are lugging around over 2 kilograms of dead skin, of which several billion tiny fragments are sloughed off each day. Run a finger along a dusty shelf and you are drawing a pattern very largely in old skin.