The Accidental Species: Misunderstandings of Human Evolution (12 page)

Finding fossils is a chancy business. We are therefore entitled to ask the following questions: What would our ideas about evolution have been like had none of the fossils we’ve discovered been found—but an entirely different collection unearthed instead? Would we still use this collection to justify a view of evolution based on progressive increases in complexity, culminating in Man?

I shall consider this by analogy with something we all know—the English language, so rich and strange, but something we take for granted. English is a first language for many, and a second for many more. English is among the top five most influential languages in the world,
¹
and so ubiquitous that, as an English speaker, even the most remote parts of the world don’t seem so far from home.

It didn’t have to be that way. English is subtle and flexible, to be sure, but there is no particular reason, inherent in the language itself, why it should have achieved its present dominance over Latin, say, or Portuguese, or Malay, or, come to that, many of the other languages among the 6 or 7,000 spoken today.

The current success of English can be put down to historical accident, determined by two things. First, by its spread between the seventeenth and early twentieth centuries as the language of the British Empire, the most populous and geographically the most extensive commercial concern in history.
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Second, by the fact that it just happened to be the language of those former British colonies that, as the United States of America, grew to eclipse their progenitor in influence and power.
³

Neither the growth of the British Empire nor of the United States was inevitable. Had Wolfe failed in Quebec in 1759, say, and the Royal Navy lost to the French at the battle of Quiberon Bay in the same year,
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I might be writing this book in French: or Spanish, perhaps, had the Armada not been blown off course in 1588. Or German, had Hitler pressed his advantage at Dunkirk. These examples might seem playful, but they are meant to be serious. Things that we take for granted, and assume to be the way they are through some inherent superiority or the inexorable machinations of destiny, might so easily have turned out differently.

Historians are now quite used to considering the might-have-beens as well as the documentary facts, and reconstructing “counterfactuals,” scenarios of how things might have turned out had events gone
slightly differently. These are more than merely speculative exercises. For example, documents still survive showing how the Nazis planned to govern the Soviet Union, had they managed to conquer it.
⁵
Pioneering Americans were brought up to believe in “manifest destiny,” the doctrine that the United States would spread from coast to coast. That it did so might to some extent have been self-fulfilling prophecy. However, historian D. W. Meinig has challenged this, showing that the United States might easily have been much larger than it is—or much smaller—had certain policies been followed that were instead ignored, or put aside instead of being pursued.
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And so for the English language. Despite its modern currency, English began as a language—we call it Old English—that is as unintelligible to an untutored modern English speaker as, say, Swedish. It was spoken in England and lowland Scotland for about six centuries, from the invasions of Britain by the Angles and Saxons in the fifth century, until the Norman Conquest drove it to the brink of extinction. The few fragments of Old English literature that have come down to us from that remote yet immense period have survived thanks only to blind chance. For example, 30,000 lines of Old English poetry are known to us—all that’s left of more than six hundred years of poetry and song. For comparison, Shakespeare’s plays total some 150,000 lines, written over a period of twenty-four years. What’s more, almost all Old English verse is found in
just four surviving manuscripts
, all written in the West Saxon dialect of Old English around the year 1000—which does not mean that we knew who originally composed them, nor in what language.
⁷

Perhaps the best-known example of Old English that survives today is
Beowulf
. This is a long poem written in alliterative verse (a style characteristic of the period) concerning the adventures of the eponymous hero and his battles against a succession of monsters. The fact that
Beowulf
is a staple of the school and college curriculum, and can be found in the proverbial All Good Bookstores,
⁸
in the original Old English and in Modern English translation, inures us against the revelation that there is only one known manuscript of the poem—and that narrowly avoided being destroyed in a fire in 1731.

We are so used to the mass dissemination of information that it’s hard for us to imagine a time before the invention of printing, when books were fabulously rare and expensive custom-made products, copied from an original (or from other copies), with great labor, and by
hand. The fact that literature before the age of print could be reproduced only very slowly had an important consequence for knowledge. That is, it was once very much more fragile than it is now, much more prone to extinction. Given the prevalence today of print and electronic data storage, it would be very difficult, nowadays, to completely expunge all traces of
Hamlet
, say, or
Middlemarch
. Before printing, however, to put just one monastery library to the torch would have been to consign hundreds of unique manuscripts to total oblivion, irreparable and irretrievable.

If just one manuscript of
Beowulf
survives, one can hardly imagine the numbers of other works in Old English that once existed but that have been lost.

The facts of the manuscript speak for themselves. Apart from showing signs of fire damage, the
Beowulf
manuscript (you can see it on permanent display at the British Library in central London) is certainly a copy. It was made sometime in the eleventh century, presumably from another copy. The date of the composition of the original is not known—the poem might have been in existence for two or three hundred years before the single surviving copy was written. This suggests that the poem started as oral tradition; that there must have been a number of earlier written versions, all now lost; and that there might not have been a single, definitive, “official” version.

The single copy also shows signs of having been bowdlerized. The setting of the story is pagan, and concerns pagan values, but the copy we have was written many centuries after England had been Christianized. It is possible that the several references to Christianity in the poem are later additions, either in the manuscript we have—or in earlier versions, all now lost.

That tales once existed in Old English of which we now have no knowledge is illustrated by the use in
Beowulf
of words found nowhere else in the surviving corpus of medieval literature, but which are unlikely to have been neologisms created specially for the occasion; and obscure references to stories, whether of fact or fancy, that the contemporary audience would have found familiar, but which have since been lost and so mean nothing to us. Proof in the breach comes with an episode in
Beowulf
concerning a battle between two warlords, Finn and Hengest—an account of which same incident subsequently turned up in another fragmentary manuscript.
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What would our view of the past be like had no copies of
Beowulf
sur
vived? And what of the alternatives? For example, if we think that the library of Old English is thin, of the native literature of England before the Anglo-Saxon invasion we know even less. What would our ideas of the languages, literature, and customs of the Dark Ages have been like had the single remaining manuscript of
Beowulf
been destroyed in that fire in 1731? What would our ideas have been like had we found instead an epic poem of King Arthur written in medieval Welsh? This is not idle fancy—the existence of such lost works was hinted at by Geoffrey of Monmouth in his
History of the Kings of Britain
, written in Latin in the twelfth century. Or what, perhaps, of tales in an otherwise obscure language such as Pictish, whose scant relics remain completely undecipherable?

The point of this is to show not only that history turns on a hair (the outcome of events is “contingent,” as Stephen Jay Gould put it in
Wonderful Life
) but also that our present-day view of history is sensitively conditioned by those few and arbitrarily sampled fragments that have survived the ravages of time. I call this the “Beowulf effect.”

As with fragile, unique handwritten scrolls from a thousand years ago, the chances of any living creature becoming a fossil are extremely remote. What’s more, the fossils we have document an almost infinitesimally tiny, entirely arbitrary, and almost certainly unrepresentative selection of the range of living creatures that once existed, the preservation of any one depending very largely on luck. The fossil record shows the Beowulf effect in action.

The word “fossil” derives ultimately from the Latin verb
fodere
, which means “to dig.” Baldly, fossils are things that are dug up. More specifically, fossils are physical signs of the presence of creatures that lived long ago, and that were buried. Fossils might constitute the actual physical remains of the creature—its bones, its shell, or even its DNA—but this is exceptional. More commonly, they are what happens when the tissues of a dead creature are replaced by minerals that percolate into the buried remains through the groundwater, creating a stony representation of the shape of the creature. The fossils of sea urchins that my family and I find on Cromer beach now and again aren’t made of the actual material from which sea-urchin tests are made, but from chalk, or flint, a rock that forms when silica-laden groundwater percolates into chalk.

In some cases, especially when the creatures have become buried in an oxygen-poor environment such as the mud at the bottom of a stag
nant lake, the bacteria responsible for breaking down the corpse will leave very detailed impressions of that corpse in the form of the deposits of their own mineral waste products. In other cases, fossils are the petrified impressions that a creature leaves in sand or mud—the cast of a shell or, more evocatively, signs of past activity, such as a trail of footprints, a bite mark, or a burrow.

What can’t be emphasized strongly enough is that the chances of a creature leaving any trace at all in the geological record are vanishingly small. In the wild, many organisms—perhaps most of them—are eaten by predators. Should animals or plants live long enough to die without their bodies having been consumed by a predator, their remains are almost always recycled within days. Their soft tissues are soon eaten by scavengers, and any remnants are broken down to nothing by fungi and bacteria. The hard parts—whether bones or shells—are pulled apart and dispersed, and time eventually grinds them to powder. To stand any chance of fossilization—to become a recognizable memorial to an otherwise evanescent existence—the body of a creature must remain sufficiently intact until it becomes buried or otherwise put beyond reach of the normal agents of dispersal and decay. A fossil is therefore a sign of some rather unusual circumstances in which the normal course of events has been cheated.

Fossilization, if it occurs at all, almost always happens underwater, and to those parts of a creature that are most resistant to physical breakdown. This explains why the fossils we have are overwhelmingly those of the hard shells of animals that spent their lives in water, are therefore likely to die in it, and so stand a chance of becoming buried in the sediment at the bottom of the sea or in a lake. It is no coincidence that the collections of most amateur rock hounds contain fossils of sea creatures—clams, ammonites (the shells of creatures related to squid), belemnites (ditto), sea urchins, trilobites (marine creatures that looked rather like pill bugs), perhaps a fish or two, and the occasional bone of a marine reptile such as an ichthyosaur (whose bobbin-shaped vertebrae make excellent ash trays, I am told), but rarely the remains of ancient land animals such as dinosaurs. This is because land animals tend—of course—to die on land, and their remains disperse quickly before they can be buried. Fossils of land animals are usually what are left once the uneaten scraps of some hapless corpse get washed into a watercourse after everything else has finished with it. Transfer to water and subsequent burial break up the remains even further. This is why
fossils of land animals are rarer than those of aquatic ones, and why even the best of those that survive long enough to be recognizable as the remains of living things are in general fragmented and in very poor condition. The majority of fossils of land vertebrates consist of teeth—this is because enamel is very much harder and more resilient than any other tissue, and is the last to be broken down.

Land animals that lived in dry conditions but close to water (a somewhat conflicting set of circumstances) are the least unlikely candidates for fossilization. Dinosaurs sometimes fall into this category, as do hominins. Creatures close to water sometimes fall in, or are pushed. There are, very occasionally, mass-death assemblages of dry-land creatures that have been overwhelmed by floodwater and quickly buried. The bodies of creatures that live in hot, damp tropical forests are almost always decomposed by other creatures and hardly ever fossilize; the bodies of animals that live at high altitude are broken up and decomposed long before they can be interred underwater in any recognizable state. Ancient hominins—at least, the ones we know about—lived in the lowlands, often near water (or in caves—another location that ups the odds of fossilization), so their fossils, while meager, are sufficient to mark their having existed. Chimpanzees are forest creatures, and although they have been evolving for precisely the same length of time as hominins, their fossil record consists, so far as is known, of just a few half-million-year-old teeth.
¹⁰
Gorillas, like chimps, live in tropical forests, sometimes at high altitude, and have been going their own evolutionary way for much longer than either chimps or hominins, but their fossil record is completely blank. Hundreds of thousands of generations of gorillas have come and gone, but apart from the creatures alive today or whose skeletons are preserved in museums, there is not one single sign, not even a scrap of half a tooth, to betray their lineage having existed, as it surely has done, for the past 7 or 8 million years.