The Accidental Species: Misunderstandings of Human Evolution (23 page)

Much of the foregoing is written at least in part in jest. I do not claim that bipedality evolved for the purpose of sexual display. The point I am trying to make is one that armchair theorists of bipedality fail to understand: that there can be no simple relationship between a proposed cause and a proposed effect. The consequence of one change has an impact on many other traits or adaptations, until the whole body is affected. In no trait does this seem truer than in bipedality. Bipedality means more than just standing on two legs. It requires the wholesale modification of the body, not all of it very effective.

But bipedality has evolved considerably since the first appearance of bipeds: it did not appear all at once. The awkward gait of the very primitive fossil hominin
Ardipithecus ramidus
(at 4.4 million years old, the earliest for which good skeletal evidence is known) shows that the first bipeds were not as refined as modern humans.
²⁹
They could stand upright, they could walk, though not as upright as modern humans, but they probably could not run very well. However, footprints attrib
uted to the fossil human
Australopithecus afarensis
(Lucy) from a million years later show that by this time, creatures close to the human lineage could walk just about as well as modern humans. Even so, the skeleton of this creature was still very different from modern humans: Lucy could walk, but her skeleton suggests that she might have been a better tree climber than modern humans are.
³⁰

The act of standing upright was followed, in sequence, by walking and then running—two gaits that demand very special, and rather different, adaptations. Daniel Lieberman and Dennis Bramble have recently proposed that many features of modern humans appear to be adaptations not to walking, as such, but to long-distance running.
³¹
These include a range of features throughout the body not directly connected with the legs and feet.

Here are just two examples.
Homo erectus
and modern humans have barrel-shaped rib cages, in contrast to the cone-shaped, wide-bellied rib cages of earlier hominins. This means that later hominins had “waists,” which would have allowed the counterrotation of the arms relative to the legs while running. This is an extremely important aid to balance. Such counterrotation, however, would move the head from side to side with each stride, if it weren’t for a corresponding reduction in the neck musculature to allow the head to be suspended independently. In human beings there is a ligament—the nuchal ligament—that connects the back of the skull with the back and shoulders. This allows the posture of the head to be maintained without effort. This ligament is not found in apes. It
is
found, however, in predators such as dogs, which track and hunt over long distances without tiring—just as traditional hunters do.

The current consensus is that bipedality was the first distinctive feature to have evolved in the human lineage, long before the expansion of the brain. Before many fossils had been discovered, of course, the view was that the large brain of humans evolved before the upright, bipedal stance: this conceit explains why the Piltdown forgery was so effective.

Bipedality might be a distinctively human feature—but is it “special”? Not really—apes have a variety of peculiar modes of locomotion, from quadrupedal knuckle walking (gorillas and chimps) to movement with all four limbs as hands (orangutan) or the forelimbs alone (gibbons). The evidence from
Ardipithecus ramidus
suggests that the distinctive modes of locomotion in each modern ape species are products of their own very special evolutionary circumstances, and not some relics
of ancient times. Some extinct apes, not directly related to hominins, were even bipedal.

As a final note in this chapter, I refer you to the strange case of
Oreopithecus
. This ape lived in the Late Miocene (7–9 million years ago) and was endemic to a Mediterranean island whose fabric now forms parts of the Italian region of Tuscany.
Oreopithecus
was, in its own way, a biped, so much so that its hands were sufficiently free to allow for a precision grip, in which the tips of the fingers and thumb can be pressed together, allowing fine manipulation—something often assumed to be exclusive to toolmaking humans.
³²
But
Oreopithecus
was a very distant cousin of hominins, not an ancestor.
³³
Its bipedality was not a harbinger of technology, holding babies close to its chest, or anything else. The free hands of
Oreopithecus
were not, as far as we know, employed in making tools, thereby refining “planning depth,” swiftly followed by the conquest of the earth. Whether bipedality in the species was connected with sexual display will probably remain forever unknown. We do know that bipedality did not save it. As far as we know,
Oreopithecus
remained confined to its island home, where it quietly became extinct. For
Oreopithecus
, bipedality was a trait as individual as any other variety of ape locomotion, not the first step in some progressive path of transformation between Ape and Angel.

And the same is true for us.

8
:
The Dog and the Atlatl

One of my favorite items of technology has an ancient pedigree. It’s a springy, flexible rod about fifty centimeters long, with a handle at one end and a cup at the other to hold a tennis ball. I use this to throw, with ease, tennis balls for my dogs to chase and fetch, much farther than I could throw them unaided, even with great effort. If on any given day you can’t find me at home or at the office, try the beach: there you’ll find me using the ball thrower to throw balls for my dogs to retrieve.

The principle is simple—by lengthening my arm, it increases leverage. By expending the same force, the ball leaves the end of the atlatl with greater velocity than it would from my unaugmented arm. Devices like this have been used to throw darts and spears for tens of thousands of years. Mine gets a modern makeover in that it’s made of plastic rather than the wood, bone, or antler of the originals. The material aside, the atlatl or “spear thrower” is one of human technology’s more enduring design classics.

Technology needs a definition. To most people, I suspect, the word “technology” conjures images of complicated machinery or modern electronic hardware. But such modern technology, even if apparently changed beyond recognition, is really a compressed combination of many much simpler technologies.

Take, for example, the iPad on which I wrote much of the draft for this book. It is made of plastic and metal. The plastic comes from the chemical processing of petroleum, reliant, at root, on nineteenth-century chemistry based on eighteenth-century engineering. The metals are occasionally exotic, but the basics of mining and metalwork go back to antiquity. The electronics in my iPad are based on VLSI chips (very large scale integrated) of what twenty years ago were called microprocessors, themselves condensed versions of transistors (invented in the 1950s), and before that, vacuum tubes that go back to a nineteenth-
century fusion of once-separate technologies such as metalwork and glassblowing. The programming that allows me to write on the iPad has a distant ancestor in punched-paper tape used to program vast computers made of arrays of vacuum tubes: and at the business end I use writing, a system of symbols for the recording of ideas whose concept is (by definition) as old as history. When looked at critically, even the most advanced technologies used today by human beings are variations and combinations of earlier, simpler ones.
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In any case, the kind of technology in use for most of human existence has been of the order of the atlatl: simple machines that allow one person to exert greater force than he might have achieved unaided. Give me an atlatl long enough, as Archimedes might have said, and I could throw a tennis ball from here to next Tuesday.

How does one define technology? One definition might indeed encompass all those many objects that people create to do things they might not be able to achieve (or might achieve less well) unaided—things like the atlatl. Such a definition extends well beyond objects we recognize as tools or weapons, to the clothes and dwellings that allow us to live in places that humans might not otherwise have penetrated, to the pottery used since antiquity to transport or contain such items as nuts and grain, fire and water, and in which food might be cooked.

Cookery in particular is believed to have had a profound influence on human anatomy, physiology, and social structure.
²
Cooking food breaks down hard or woody tissues, neutralizes toxins, kills potentially harmful bacteria and parasites, and makes more nutrients available to the diner. This increase in efficiency meant less time spent foraging and digesting, allowing more time for social interaction—aside from the fact that cookery tends to be a social and sociable activity in itself.
³
Some scientists think that cookery was followed by a reduction in the mass of the jaws, teeth, muscles, and digestive tract, and perhaps an increase in the mass and capabilities of the brain. It is not trite to suggest that humans have been modified by their own technology.
⁴

This definition of technology—those things we create outside our own bodies that allow us to do things we could not have done unaided—also encompasses things that we might not describe as technological at all. Technology might be said to include such imponderables as legal codes and financial structures. Laws make it easier for people to live together harmoniously. Financial structures—from coins and notes to credit derivative swaps and futures contracts—allow us to exchange
goods without having to physically carry them around ourselves. Laws and money are not technology in the sense of tools you hold in your hand. Rather, they represent social conventions. The twenty-pound note in my pocket doesn’t actually
do
anything—it is merely a promise by the Bank of England to underwrite any transaction made with it to that value. Once upon a time such transactions were backed with a real commodity (gold), but no longer. My twenty-pound note is itself a real
thing
created by the technology of printing, but represents another sort of technology based on social contract. Technology, therefore, includes things that we might otherwise regard as social conventions rather than physical objects.
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“Money” only has “value” inasmuch as we all agree that it does. Therefore, the importance of such things as money—and with that, wills, contracts, and treaties—lies not in their physical form but in the ideas they represent. If this seems somewhat rarefied to be technology, consider that people are given life or condemned to death as surely by abstractions such as treaties and the passage of money as they are by more concrete examples of technology such as antibiotics or nuclear weapons.

If such intangibles as money can be regarded as technology—spoken of in the same breath as, say, swords and plowshares—then perhaps the earliest and most enduring example of technology is something one might not regard as technological at all: the domestic dog.

Not for nothing does the dog bear the soubriquet of Man’s Best Friend. For tens of thousands of years, dogs have made human beings safer, helped them herd other domestic animals and hunt wild ones.
⁶
In the old days, when, to paraphrase Jared Diamond,
⁷
we didn’t do all our foraging in supermarkets, I’d have gone hunting with my bone or antler atlatl and some spears, and a fast-running dog to chase down the prey and retrieve the kills. These days, my dogs and I reprise the same activity, purely for pleasure and exercise, with a plastic atlatl and some tennis balls.

Modern dogs have been bred for a variety of purposes, some quite remote from what we assume to have been their original uses, such as hunting or retrieving game (Heidi, my golden retriever), ridding campsites of rodents (Saffron, my Jack Russell terrier), guarding against intruders (both), and herding livestock (neither). Modern dogs are used in such sophisticated tasks as helping blind and deaf people get around busy cities, rescuing people washed into the sea or buried under rubble,
sniffing out explosives and contraband, but perhaps most of all to provide companionship for people.

My friend Brian Clegg, a full-time author, says that the most important piece of equipment a writer can own is not a computer, nor even a pen, but a dog. Writing is a solitary business, and a dog provides company without being intrusive. One can always postpone a trip to the gym, but those appealing doggy eyes and waggy tail have a way of persuading the writer to take regular breaks for exercise, whatever the weather, during which the writer can think about what he has just written and plan the next bit.

How can a dog count as technology? It fulfills my definition in that it allows humans to do things that they might not have been able to have achieved unaided (hunting, herding, sniffing out drugs, eyesight to the blind, and so on). My definition also specifies that technology is created for its purpose. The domestic dog is definitely a creation that would not have evolved naturally, having been modified quite extensively in both behavior and appearance from its ancestor, the wolf. Most cases of domestication involve humans breeding and selecting animals and plants in true Darwinian style to optimize them as producers of food. Dogs, however, are a special case of one social carnivore being domesticated by another social carnivore for mutual benefit—a kind of symbiosis.

How far back does human technology go? We know for certain that technology antedates modern
Homo sapiens
. The earliest tools that can be recognized as such are chipped pebbles from Ethiopia that date back 2.5 million years, although it is possible that hominins were using sharp stones to butcher carcasses of other animals (such as antelopes) as long ago as 3.4 million years ago.
⁸

The earliest stone tools don’t look like much, and it takes an expert eye to tell them apart from pebbles broken by natural causes or by accident. However, some stone tools, notably the hand ax—that canonical item in the Stone Age toolbox—are objects of remarkable beauty, and show evidence of extraordinary craftsmanship to rival anything one might find in, say, the workshop of a trained cabinetmaker or stonemason today.