When all that story’s finished, what’s the news?
In luck or out the toil has left its mark:
That old perplexity an empty purse,
Or the day’s vanity, the night’s remorse.
W. B. YEATS
IN THE CAVERNOUS INTERIOR of the Excalibur Hotel in Las Vegas, Nevada, there are ranks of gambling machines lined up like gaudy soldiers on parade, each one to a common design, though subtly different. They invite you to make a close inspection. The machines are designed to be close to human height. You prop yourself before them on skimpy stools, or stand to attention inspecting the arcane rules that govern how you may be paid back richly as you gamble. The winner takes all.
It is a temple to chance. Between the machines there are roulette wheels, spinning symbols of chance itself. Punters cluster intently around the wheels, seeking by willpower alone to guide the little ball into the numbered haven of their choice. There are various ways in which to place your bets. The long shot is to bet on a single, winning number, with the faint possibility of colossal returns. Or, alternatively and more conservatively, you can bet on red or black. Whatever you do, the table has the edge. The odds can be evaded temporarily—enough to fund an occasional small fortune. But the odds will reassert themselves in the end with the inexorability of a mathematical certainty.
The bleeping, winking, sleepless cavern at Excalibur knows neither day nor night. It lives under perpetual, but dimmish, electric light. It is maintained at the temperature of a warm spring day. The temperature outside is about 100 degrees Fahrenheit—not a particularly hot day for this part of the world. All around there is the Nevada Desert, and if the water dried up, or the electricity were switched off, the desert would soon reassert itself. The people would depart in their Chevys and suburbans, and the whole absurd farrago of neon and paste would crumble away; and soon hot winds would excoriate the boulevards, and whistle among the abandoned ionic capitals of Caesar’s Palace, around the glistening Nilotic pyramid of the Luxor, and beat against the castellated concrete of Excalibur. Maybe, at that time, a shy pronghorn antelope would pick delicately among the debris, coming down from the hills in search of rewards from remnants left behind by departing men and women. Lizards would crawl out to bask upon abandoned stretch limousines. Those creatures lacking in presumption, but rich in the qualities required for survival against the odds, would inherit the Strip. For the meek survive, even if they don’t inherit the Earth.
Life—as everyone knows—is a gamble. Chance promotes or damns according to the whim of history. The analogy of permutations in a game of chance has long been applied to genetic mutations, spontaneous changes in the genetic code. Like the vast ranks of gamblers in Las Vegas who come away with nothing, most mutations also lead to nothing. They do not result in an increase in fitness. Some are lethal—as might be the production of a wingless butterfly. Others might put the mutant at a disadvantage—a new colour pattern might not be favoured by a potential mate, for example. But those rare mutations that hit upon an advantageous combination produce the big payoff—the jackpot. They are rewarded not in the gross currency of quarters or dollars but in the irresistible coin of many successful offspring. Unlike the lucky gambler in Excalibur or Caesar’s Palace the luck of the successful gene is passed on to make luck for future generations.
Through the 4,000 million years of life’s history I have trodden but one of countless possible paths. One recurring motif has been luck of a different order. Those animals and plants that survived the death of the dinosaurs did not prosper because of a small change in genes at the critical time. They already had whatever was needed to survive—by another sort of luck. Small, warm-blooded mammals and birds, together with insects and magnolias, survived the crisis at the end of the Cretaceous that extinguished dinosaurs and ammonites because they were already equipped to survive, not because they invented some wheeze at the last minute. The whole course of life hinged on the fact that some of the animals that appeared in the Cambrian were unlucky enough not to survive, and thus failed to propagate their designs in their descendants. Recall, too, the constant splitting and rearrangement of the continents as the great plates that make up the Earth’s surface cruise in their leisurely fashion over the surface of the mutable globe. It is luck—it must be luck—which determines which animals, when and where, are attached to a particular continent. As Antarctica was carried towards the South Pole after the break-up of Pangaea its cargo of terrestrial animals was doomed to die. Rare fossils tell us that there were mammals there before the ice caps grew. Doubtless there were mutations galore, some of which favoured cold-tolerant species over less tolerant ones, as the climate deteriorated. But that was useless in the face of implacable ice and everlasting winters, a cold that freezes blood. This was far, far worse than Las Vegas with the water and electricity turned off. It was bad luck.
Geography can be just as creative. When the island of Hawaii was born from the eruption of oceanic basalt lavas it was isolated within the young Pacific Ocean, far from the nearest continent. It was a tabula rasa upon which Nature might write. A tropical climate almost guaranteed that it would be fruitful. Volcanic soil is rich and capable of nourishing any plants that can reach it. Some did. Seeds floated, brought by storms; other seeds blew in, light as thistledown, borne in upon delicate parachutes carried by the breeze. Distance was selective—very few species of animal landed safely. For birds it may have been less difficult to reach the freshly green island, but even so the founding species were small in number. There may have been as few as seven different insects that won the lottery. But good luck here provoked a fever of creative evolution—the opposite of the Antarctic blight. From the few species that arrived in this evolutionary Eden dozens of species arose. Since change could only work upon what material was to hand, wonders happened. Harmless pollen-eaters evolved into predators; small insects became large; many specialists arose to eat the newly native flora. None of these unique species was found outside Hawaii. Good luck was fenced off from the rest of the world.
But it has become bad luck, now that contact has been established with the world, thanks to human colonization. For, in a tragic mirror-image of that original creativity, introduced animals such as the rat are forcing out the erstwhile lucky ones from their private Eden: it is a reversal of fortunes.
Australia also carried its cargo of marsupials southwards, and I have described how they, too, evolved richly on their own. Man’s arrival as part of the diaspora of Homo sapiens also coincided with the decline of some large marsupial herbivores, but more damage has been done by the greedy ways of modern humans and their cats. None the less, not all Australia’s endemics were losers when faced with competition from the wider world. The eucalypts have been Australia’s contribution to the diversity of arboreal life. There are great forest trees like ironbarks, or drought-tolerant, dwarf mallees, or the white-barked ghost gums—no more varied range of designs for every purpose exists in the vegetable kingdom. They have prospered around the world against all comers. I have sat under Eucalyptus groves of great height in western Argentina; the local acacias are dwarfs by comparison. Eucalyptus leaves dangle in the sun, fending off its full blast. Their fragrant oils help to slow transpiration. They can even stand fire whipping through their glades, hot and fierce, but leaving the cool heart of the trees untouched to sprout again. They are world-beaters. Now, they line roads in Andalucia, thrive on university campuses in California, and decorate the town squares in Portugal. A strong-minded woman of my acquaintance once tried to argue with me that eucalypts were natives of Portugal—taken by early mariners to Australia—such was her conviction about how naturally they fitted into the Iberian landscape. Evidently, the isolation that ultimately proved bad luck for many Australian marsupials when they faced competition from placental mammals was good luck for gums. The skills acquired by trees along creek and by billabong proved to be useful elsewhere. We cannot simply pin labels on products of the intricacies of 4,000 million years of the history of life and specify doom for some and unlimited prospects for others. There will be surprises.
For life, unlike any gambler in Las Vegas, has made its own luck. Every one of the innovations on which my story turns—from the inception of photosynthesis, which modified the primitive atmosphere in a way suitable for “higher” life, to the colonization of land and, eventually, the skies—both altered the odds and reset the tables. A world so enriched might better endure the slings, not to mention the arrows, of outrageous fortune; life has survived the worst catastrophes that could be dealt by the cosmos: bolides have been beaten by beetles and barnacles. These mass extinctions were times when, briefly, all bets were off. At other times, life survived ice ages and changes in sea level, or fluctuations in the atmospheric concentration of carbon dioxide.
In short, life has gained an edge.
Nor is it trivial to draw a parallel between the biography of life and an autobiography. The interweaving of episodes from my own scientific life into the narrative of the biosphere does more than provide the occasional diversion. From my early days in Spitsbergen, luck—fortune, if you prefer—has played a part in deciding which direction I have taken. On occasion, a course has been decided by decisions almost as arbitrary as the spin of a coin. Our lives are not merely the inexorable unwinding of the consequences of our own genome, for all that it would be foolish to deny that genes are extremely important. One might compare genes with a good (or bad) poker hand—which can be modified during the course of play, but which can never be ignored. Luck, the environment, nurture, all contribute to the personal biography: “in luck or out the toil has left its mark.” But the individual also has use of his free will to make choices—to make his own luck. Hence I see more than a facile resemblance between our own biographies, with all their quirks and minor setbacks and inconsequences, and the grander story of Life itself. Stephen Jay Gould’s notes on the contingencies which have shaped the history of life amount to the observation that no two human biographies are identical, and no life would unwind twice in the same fashion. It is, in a sense, a trivial point, since clearly no biography can ever be relived. There is only one narrative. This was an observation made by Sir Karl Popper in The Poverty of Historicism. But a life remains a compromise between what is dealt, and what is experienced, mediated by the effort of will. The greater story of life on our planet is partly a story of luck, of changes imposed upon the world by earthly and universal forces, and partly a story of genes, and finally a product of the changes life itself has wrought to modify the odds.
We cannot easily imagine a planet stripped of its forests or with an atmosphere rancid with sulphur, or thick and suffocating with carbon dioxide. The changes made upon the globe by life have altered the way in which the very rocks are eroded. Green-clothed hills are sponges that absorb energy which would have scoured away slopes in the Palaeozoic. Even now, we are only beginning to see the true complexity of the tangled skein of life, let alone understand its workings. I like Goethe’s description of “the eternal Weaver’s masterpiece: look how one press of her foot sets a thousand threads in motion—how the shuttles dart to and fro, the flowing strands intertwine and a thousand connexions are made at one stroke!” As I write this there is a debate about whether the biosphere extends deep into the Earth, because living bacteria have allegedly been recovered from within rocks recovered from boreholes. I have no idea how the debate will be resolved, but “at one stroke” it could double the biological sphere and add yet further to the intimate complexity that links life with its geological matrix.
The last component of this complexity is consciousness. The rules of the evolutionary game were changed at such a critical point in the evolution of Homo. Bishop Berkeley’s observation may not be right that, were it not for the contemplation of a conscious mind, the world might cease to exist, but it is assuredly true that perception has altered all the rules that once held indifferent sway over organic evolution: because choice is the companion of consciousness. In consciousness the narrative of history and that of the individual finally meet. The choices that modify the personal legacy of our genes, or the exigencies of our environment, are paralleled by the influence that human consciousness as a whole may exercise upon the narrative of the future. Our future entails that of the world; we have control of it, if we could only have control of ourselves. Human conscience and consciousness are closely allied.
It is interesting how military metaphors have often been used to describe what I prefer to think of as thresholds which life has crossed. A dozen popular illustrated books refer to “the conquest of the land.” Who, I wonder, was the enemy in this conquest, and who the vanquished? It recalls the combative metaphors employed in disease that Susan Sontag described: “the struggle against cancer, the patient fighting for life, the battle against AIDS.” This has a heroic subtext, like Theseus grappling with the Minotaur. Yet one of the remarkable things about the important thresholds in the biography of life was that they were explorations, innovations. The “enemy” was the challenge of a new physiology, no cryptic Minotaur. The metaphor seems instinctively to be appropriate, probably because the struggle for success is part of the legacy of classical Darwinism. The implication is: no change without challenge. This may be the stuff of regular evolutionary change (some scholars do not believe so), but when thresholds were crossed life gloriously broke free of combat, at least for a while, and lost itself in creative innovation, like those pioneer insects on Hawaii.
The shape and tempo of the story of life as a whole resembles that of the history of mankind, a single species. I think of Maurice Ravel’s dance, Boléro, which starts slowly, uneventfully, a long series of slight variations upon a recurrent theme, gradually gathering pace, shifting from one instrument to another, while an underlying pulse goes on and on. From time to time there are shifts in key, then more instruments join in, and the pace and excitement build, until, at the end, it is a scurrying, swirling mass of interwoven instrumental activity. The slow growth of brain size in humans took several millions of years. To be sure, the innovation of tool-making was a threshold, but how similar those tools remained for more than a million years, slowly turning changes on familiar themes. But technology built itself up, and interactions between a growing population increased, until there was a sudden flowering of stone tool types, building techniques, domestication of animals and plants. In a geological instant society mushroomed in all its uncountable complexity. Similarly, for thousands of millions of years the bacterial and algal world slowly, almost imperceptibly changed—a long, leisurely theme repeated and slowly modified—while within the last 500 million years the richness of life has increased a thousand-fold again. The history of one species, the one to which the writer and reader belong, took a chapter of this book to sketch in only the broadest outline. Imagine if a narrative as complex were known for all the other millions of species living in this tangled and prolific biosphere; why, the paper used to print their histories would strip the trees from the world! Yet the chances are that every species has a story worth telling. In your mind’s eye imagine you are an eagle easily gliding above the rain forest canopy, and as far as you can see in every direction, there are billowing canopies of trees reaching upwards into the light. Each one of these trees might represent the branching history of a living species, and the forest itself might be a crude representation of the density of the historical past. We shall never know every detail of every tree, but we can understand the vitality of the whole, and thus see the forest for the trees.
My tale stops where civilization starts, and where prehistory blurs into history. This is the moment when records begin, when humble steles or grandiose monuments tell of mankind’s inhumanity, or his aspirations to godliness. Appropriately enough, some of the earliest writing is biographical, inscriptions trumpeting the achievements of kings. The truth of a life also depends on the selection of its incidents, no less than does an account of a civilization. As such unnatural selection proceeds there is also the possibility of lies and unwitting deception; although Nature is full of camouflage, we are the first animal ever to deceive ourselves.
A review of the history of life should provoke awe, above all else. As Goethe said, “Zum Erstaunen bin ich da”—I am here to wonder. There are no trite moral lessons, nor are homilies desirable about cycles of history which are destined to come around once more. It is only certain that there will be change, and change again. Man will doubtless be an additional cause of it. The difference from any of the hundred incidents I have described in this biography is that we should be able to anticipate effects. Let us hope that we act wisely. Spinning tumblers, geared by chance, will still intercede in our fate. There may be bolides, there will certainly be climate change, there may be incidents with no precedents.
Life will probably cope.