A Short History of Nearly Everything

by Bill Bryson

It then plunges to as low as minus 90 degrees Celsius in the mesosphere before skyrocketing to 1,500 degrees Celsius or more in the aptly named but very erratic thermosphere, where temperatures can vary by over 500 degrees from day to night—though it must be said that “temperature” at such a height becomes a somewhat notional concept. Temperature is really just a measure of the activity of molecules. At sea level, air molecules are so thick that one molecule can move only the tiniest distance—about eight-millionths of a centimetre, to be precise—before banging into another. Because trillions of molecules are constantly colliding, a lot of heat gets exchanged. But at the height of the thermosphere, at 80 kilometres or more, the air is so thin that any two molecules will be miles apart and hardly ever come into contact. So although each molecule is very warm, there are few interactions between them and thus little heat transference. This is good news for satellites and spaceships, because if the exchange of heat were more efficient any manmade object orbiting at that level would burst into flame.

The process that moves air around in the atmosphere is the same process that drives the internal engine of the planet, namely convection. Moist, warm air from the equatorial regions rises until it hits the barrier of the tropopause and spreads out. As it travels away from the equator and cools, it sinks. When it hits bottom, some of the sinking air looks for an area of low pressure to fill and heads back for the equator, completing the circuit.

The Coriolis effect explains why anything moving through the air in a straight line laterally to the Earth’s spin will, given enough distance, seem to curve to the right in the northern hemisphere and to the left in the southern as the Earth revolves beneath it. The standard way to envision this is to imagine yourself at the centre of a large carousel and tossing a ball to someone positioned on the edge. By the time the ball gets to the perimeter, the target person has moved on and the ball passes behind him. From his perspective, it looks as if it has curved away from him. That is the Coriolis effect and it is what gives weather systems their curl and sends hurricanes spinning off like tops. The Coriolis effect is also why naval guns firing artillery shells have to adjust to left or right; a shell fired 15 miles would otherwise deviate by about 100 yards and plop harmlessly into the sea.

Howard divided clouds into three groups: stratus for the layered clouds, cumulus for the fluffy ones (the word means heaped in Latin) and cirrus (meaning curled) for the high, thin feathery formations that generally presage colder weather. To these he subsequently added a fourth term, nimbus (from the Latin for cloud), for a rain cloud. The beauty of Howard’s system was that the basic components could be freely recombined to describe every shape and size of passing cloud—stratocumulus, cirrostratus, cumulonimbus, and so on. It was an immediate hit, and not just in England. Goethe was so taken with the system that he dedicated four poems to Howard.

Like all limestones, the famous White Cliffs of Dover, on England’s south coast, are made from numberless trillions of tiny marine organisms compressed over time into stone, and exist now as huge reservoirs of carbon.

Most liquids when chilled contract by about 10 per cent. Water does too, but only down to a point. Once it is within whispering distance of freezing, it begins—perversely, beguilingly, extremely improbably—to expand. By the time it is solid, it is almost a tenth more voluminous than it was before. Because it expands, ice floats on water—“an utterly bizarre property,” according to John Gribbin. If it lacked this splendid waywardness, ice would sink, and lakes and oceans would freeze from the bottom up. Without surface ice to hold heat in, the water’s warmth would radiate away, leaving it even chillier and creating yet more ice. Soon even the oceans would freeze and almost certainly stay that way for a very long time, probably for ever—hardly the conditions to nurture life.

It is also why water has surface tension. The molecules at the surface are attracted more powerfully to the like molecules beneath and beside them than to the air molecules above. This creates a sort of membrane strong enough to support insects and skipping stones. It is what gives the sting to a belly-flop.

The Pacific is about a foot and a half higher along its western edge—a consequence of the centrifugal force created by the Earth’s spin.

Forty years later, the question that naturally occurs is: why has no-one gone back since? To begin with, further dives were vigorously opposed by Vice Admiral Hyman G. Rickover, a man with a lively temperament, forceful views and, most pertinently, control of the departmental chequebook. He thought underwater exploration a waste of resources and pointed out that the Navy was not a research institute. The nation, moreover, was about to become fully preoccupied with space travel and the quest to send a man to the Moon, which made deep sea investigations seem unimportant and rather old-fashioned. But the decisive consideration is that the Trieste descent didn’t actually achieve much. As a navy official explained years later: “We didn’t learn a hell of a lot from it, other than that we could do it. Why do it again?” It was, in short, a long way to go to find a flatfish, and expensive too. Repeating the exercise today, it has been estimated, would cost at least $100 million.

It also answered one of the great puzzles of oceanography—something that many of us didn’t realize was a puzzle—namely, why the oceans don’t grow saltier with time. At the risk of stating the obvious, there is a lot of salt in the sea—enough to bury every bit of land on the planet to a depth of about 150 metres. It had been known for centuries that rivers carry minerals to the sea and that these minerals combine with ions in the ocean water to form salts. So far no problem. But what was puzzling was that the salinity levels of the sea were stable. Millions of gallons of fresh water evaporate from the ocean daily, leaving all their salts behind, so logically the seas ought to grow more salty with the passing years, but they don’t. Something takes an amount of salt out of the water equivalent to the amount being put in. For a very long time, no-one could figure out what could be responsible for this. Alvin’s discovery of the deep-sea vents provided the answer.

For animals that need never surface, obscurity can be even more tantalizing. Consider our knowledge of the fabled giant squid. Though nothing on the scale of the blue whale, it is a decidedly substantial animal, with eyes the size of soccer balls and trailing tentacles that can reach lengths of 18 metres. It weighs nearly a tonne and is Earth’s largest invertebrate. If you dumped one in a small swimming pool, there wouldn’t be much room for anything else. Yet no scientist—no person, as far as we know—has ever seen a giant squid alive. Zoologists have devoted careers to trying to capture, or just glimpse, living giant squid and have always failed. They are known mostly from being washed up on beaches—particularly, for unknown reasons, the beaches of the South Island of New Zealand. They must exist in large numbers because they form a central part of the sperm whale’s diet, and sperm whales take a lot of feeding.1

Nothing, however, compares with the fate of cod.

The Murchison meteorite was found to be 4.5 billion years old, and it was studded with amino acids—seventy-four types in all, eight of which are involved in the formation of earthly proteins. In late 2001, more than thirty years after it crashed, a team at the Ames Research Center in California announced that the Murchison rock also contained complex strings of sugars called polyols, which had not been found off the Earth before.

As cyanobacteria proliferated the world began to fill with O2, to the consternation of those organisms that found it poisonous—which in those days was all of them. In an anaerobic (or non-oxygen-using) world, oxygen is extremely poisonous. Our white blood cells actually use oxygen to kill invading bacteria. That oxygen is fundamentally toxic often comes as a surprise to those of us who find it so convivial to our well-being, but that is only because we have evolved to exploit it. To other things it is a terror. It is what turns butter rancid and makes iron rust. Even we can tolerate it only up to a point. The oxygen level in our cells is only about a tenth the level found in the atmosphere.

And they are amazingly prolific. The more frantic among them can yield a new generation in less than ten minutes; Clostridium perfringens, the disagreeable little organism that causes gangrene, can reproduce in nine minutes and then begin at once to split again.

Perhaps the most extraordinary survival yet found was that of a Streptococcus bacterium that was recovered from the sealed lens of a camera that had stood on the Moon for two years. In short, there are few environments in which bacteria aren’t prepared to live. “They are finding now that when they push probes into ocean vents so hot that the probes actually start to melt, there are bacteria even there,” Victoria Bennett told me.

Fungi, the group that includes mushrooms, moulds, mildews, yeasts and puffballs, were nearly always treated as botanical objects, though in fact almost nothing about them—how they reproduce and respire, how they build themselves—matches anything in the plant world. Structurally, they have more in common with animals in that they build their cells from chitin, a material that gives them their distinctive texture. The same substance is used to make the shells of insects and the claws of mammals, though it isn’t nearly so tasty in a stag beetle as in a Portobello mushroom. Above all, unlike all plants, fungi don’t photosynthesize, so they have no chlorophyll and thus are not green. Instead they grow directly on their food source, which can be almost anything. Fungi will eat the sulphur off a concrete wall or the decaying matter between your toes—two things no plant will do. Almost the only plant-like quality they have is that they root.

Even less comfortably susceptible to categorization was the peculiar group of organisms formally called myxomycetes but more commonly known as slime moulds. The name no doubt has much to do with their obscurity. An appellation that sounded a little more dynamic—“ambulant self-activating protoplasm,” say—and less like the stuff you find when you reach deep into a clogged drain would almost certainly have earned these extraordinary entities a more immediate share of the attention they deserve, for slime moulds are, make no mistake, among the most interesting organisms in nature. When times are good, they exist as one-celled individuals, much like amoebas. But when conditions grow tough, they crawl to a central gathering place and become, almost miraculously, a slug. The slug is not a thing of beauty and it doesn’t go terribly far—usually just from the bottom of a pile of leaf litter to the top, where it is in a slightly more exposed position—but for millions of years this may well have been the niftiest trick in the universe.

And it doesn’t stop there. Having hauled itself up to a more favourable locale, the slime mould transforms itself yet again, taking on the form of a plant. By some curious orderly process the cells reconfigure, like the members of a tiny marching band, to make a stalk atop of which forms a bulb known as a fruiting body. Inside the fruiting body are millions of spores which, at the appropriate moment, are released to the wind to blow away to become single-celled organisms that can start the process again. For years, slime moulds were claimed as protozoa by zoologists and as fungi by mycologists, though most people could see they didn’t really belong anywhere. When genetic testing arrived, people in lab coats were surprised to find that slime moulds were so distinctive and peculiar that they weren’t directly related to anything else in nature, and sometimes not even to each other.

It has to be said that the attributes that distinguish archaea from bacteria are not the sort that would quicken the pulse of any but a biologist. They are mostly differences in their lipids and an absence of something called peptidoglycan.

For the sake of “the principle of balance,” Mayr argued for combining the simple bacterial organisms in a single category, Prokaryota, while placing the more complex and “highly evolved” remainder in the empire Eukaryota, which would stand alongside as an equal. Put another way, he argued for keeping things much as they were before. This division between simple cells and complex cells “is where the great break is in the living world.”

The most effective strategy of all is to enlist the help of a mobile third party. Infectious organisms love mosquitoes because the mosquito’s sting delivers them directly into a bloodstream where they can get straight to work before the victim’s defence mechanisms can figure out what’s hit them. This is why so many grade A diseases—malaria, yellow fever, dengue fever, encephalitis and a hundred or so other less celebrated but often rapacious maladies—begin with a mosquito bite. It is a fortunate fluke for us that HIV, the AIDS agent, isn’t among them—at least not yet. Any HIV the mosquito sucks up on its travels is dissolved by the mosquito’s own metabolism. When the day comes that the virus mutates its way around this, we may be in real trouble.

American soldiers march with face masks during the height of the global flu epidemic, which killed tens of millions of people in 1918–19. The soldiers’ masks were completely ineffectual as the fabric was not fine enough to trap something as tiny as a virus. (credit 20.13)

Between autumn 1918 and spring the following year, 548, 452 people died of the flu in America. The toll in Britain was 220,000, with similar numbers in France and Germany.

Back here are specimens collected by Joseph Banks in Australia, Alexander von Humboldt in Amazonia and Darwin on the Beagle voyage—and much else that is either very rare or historically important or both. Many people would love to get their hands on these things. A few actually have. In 1954 the museum acquired an outstanding ornithological collection from the estate of a devoted collector named Richard Meinertzhagen, author of Birds of Arabia, among other scholarly works. Meinertzhagen had been a faithful attendee of the museum for years, coming almost daily to take notes for the production of his books and monographs. When the crates arrived, the curators excitedly levered them open to see what they had been left and were surprised, to put it mildly, to discover that a very large number of specimens bore the museum’s own labels. Mr. Meinertzhagen, it turned out, had been helping himself to their collections for years. It explained his habit of wearing a large overcoat even during warm weather.

The intention originally was to use the binomial system for everything—rocks, minerals, diseases, winds, whatever existed in nature. Not everyone embraced the system warmly. Many were disturbed by its tendency towards indelicacy, which was slightly ironic as before Linnaeus the common names of many plants and animals had been heartily vulgar.

Genus (plural genera) and species had been employed by naturalists for over a hundred years before Linnaeus, and order, class and family in their biological senses all came into use in the 1750s and 60s. But phylum wasn’t coined until 1876 (by the German Ernst Haeckel), and family and order were treated as interchangeable until early in the twentieth century. For a time zoologists used family where botanists placed order, to the occasional confusion of nearly everyone.1

Taxonomy is described sometimes as a science and sometimes as an art, but really it’s a battleground. Even today there is more disorder in the system than most people realize.

Chrysanthemum breeders are a proud and numerous lot, and they protested to the real-if-improbable-sounding Committee on Spermatophyta. (There are also committees for Pteridophyta, Bryophyta and Fungi, among others, all reporting to an executive called the Rapporteur-Général; this is truly an institution to cherish.) Although the rules of nomenclature are supposed to be rigidly applied, botanists are not indifferent to sentiment, and in 1995 the decision was reversed.

To Wilkins’s presumed dismay and embarrassment, in the summer of 1952 she posted a mock notice around the King’s physics department that said: “It is with great regret that we have to announce the death, on Friday 18th July 1952 of D.N.A. helix…It is hoped that Dr. M. H. F. Wilkins will speak in memory of the late helix.” The outcome of all this was that in January 1953 Wilkins showed Watson Franklin’s images, “apparently without her knowledge or consent.” It would be an understatement to call it a significant help to him. Years later, Watson conceded that it “was the key event…it mobilized us.”

Even when DNA includes instructions for making genes—when it codes for them, as scientists put it—it is not necessarily with the smooth functioning of the organism in mind. One of the commonest genes we have is for a protein called reverse transcriptase, which has no known beneficial function in human beings at all. The one thing it does do is make it possible for retroviruses, such as HIV, to slip unnoticed into the human system.

Altogether, almost half of human genes—the largest proportion known in any organism—don’t do anything at all, as far as we can tell, except reproduce themselves.

Further probings revealed the existence of a clutch of master control genes, each directing the development of a section of body, which were dubbed homeotic (from a Greek word meaning “similar”) or hox genes. Hox genes answered the long-bewildering question of how billions of embryonic cells, all arising from a single fertilized egg and carrying identical DNA, know where to go and what to do—that this one should become a liver cell, this one a stretchy neuron, this one a bubble of blood, this one part of the shimmer on a beating wing. It is the hox genes that instruct them, and they do it for all organisms in much the same way.

It is largely because of these complicating factors that cracking the human genome came to be seen almost at once as only a beginning. The genome, as Eric Lander of MIT has put it, is like a parts list for the human body: it tells us what we are made of, but says nothing about how we work. What’s needed now is the operating manual—instructions for how to make it go. We are not close to that point yet.

Essentially, Milankovitch had to work out the angle and duration of incoming solar radiation at every latitude on Earth, in every season, for a million years, adjusted for three ever-changing variables.