Our walk through time begins on a country lane in the village of Kingston Saint Mary, in southwestern England. This is a pilgrimage of sorts, a hike that is also a metaphorical voyage backward through 3.5 billion years of evolution. As we head down the road, a small brass band sees us off, making a joyful noise unto anyone listening—presumably not the Lord, since it’s Sunday morning and He probably thinks we should be in church instead.
But this is an unbelievers’ pilgrimage inspired by the biologist and polemical atheist Richard Dawkins. Specifically, we are re-enacting the imaginary walk through time described in Dawkins’ book The Ancestor’s Tale, a history of life that takes the usual metaphor of evolution, a tree with roots in the Precambrian and branches for all the major phyla, and turns it upside down. Dawkins begins his account in the present and traces the human lineage back to the hypothesized single cell that set the whole process in motion by dividing in two.
Our leader, Chris Jenord, has taken Dawkins’ timeline and overlaid it on the literal map of the Quantock Hills, a popular hiking area in Somerset. In homage to Dawkins, he calls it the “Ancestor’s Trail.” The branch we’ll follow is about 14 miles, ending at the cobblestone, fossil-rich beach at Kilve. The 40 or so who start here are Humans. Along the way we’ll meet groups of hikers starting from other points, representing other species.
Most of the interesting events in evolution—interesting to us vertebrates, anyway—are crowded into the last half-billion or so years, leaving around three billion years during which evolutionary changes happened relatively slowly. Accordingly, Jenord has drawn up a sliding scale relating the distance we’ll cover to evolutionary time. At the end of our walk, a single step will stand for a million years, but as we set out, one step corresponds to 10,000 years. This timeline has no relation to the actual history—geologic or biologic—of the Quantocks, which are mainly sandstone and limestone hills dating from roughly 350 million years ago. The place last played a significant role on the world stage during the Monmouth Rebellion against James II, 328 years ago. On our hike’s time scale, that’s a fraction of an inch.
With our very first step we cover all of recorded human history.
Six Million Years Ago: We have been walking for less than 10 minutes, along a path that winds gently uphill through sparse woods. We pause at the edge of a field, where a muddy track comes in from one side, and after a few minutes a half-dozen “Chimpanzees” emerge from the trees. This is the first of a number of rendezvous that we Humans will have with other hikers, many wearing masks or costumes depicting their place in the great panoply of species. The hikers wearing chimp masks lend the event a kind of determined whimsy, like a cross between Stephen Jay Gould and Monty Python.
Yet here we stand, metaphorically, at a sacred moment, the origin of the human species (or, more accurately, genus), when our lineage diverged from that of the other apes six to eight million years ago. Of course nothing special marked the moment: An ape gave birth in the forest, surrendering her offspring to the relentless winnowing of natural selection. Two lines of descent diverged and led, over some 300,000 generations, to chimpanzees inhabiting human zoos, instead of (among an infinite number of evolutionary possibilities) the other way around.
We toast the event with water, and continue walking.
140 Million Years Ago: According to Jenord’s plan we are now on an intermediate scale, in which a single step is equivalent to 100,000 years. Even at that rate, we must take 10,000 steps, roughly five miles, to cover a billion years. We emerge onto a landscape of rolling hills and gently sloping, intensely green pastures. This countryside has been inhabited and cultivated for millennia, but apart from the occasional farmhouse there is nothing to suggest that we are in one of the most densely populated nations in the world. Cattle and sheep (real four-legged ones) eye us languidly while we step fastidiously over and between the plentiful evidence of their outstanding diet. At one point our column of walkers somehow gets between a ewe and her lamb, who runs alongside us, bleating, until an opening in our ranks allows her to cross.
August days in the Quantocks can be hot, or so we’ve been warned, but today isn’t one of them, certainly not to anyone who has hiked in the American West. But as we enter a copse, a ruddy-faced Englishman walking with me sighs, expressing relief to be out of the sun—or, as we would call it in the States, the “overcast.”
On a low ridge we find ourselves at a hedge of blackberry bushes. Trisha Rogers, one of those ageless and indefatigable Englishwomen who are always solving murders on public television, reaches for a few, but finds them sour. The path turns downhill and, as it bottoms out, the berries ripen, and she pops a few into her mouth. “I guess this makes me a hunter-gatherer,” she says cheerfully.
On our timeline we have passed through one of the most consequential events in the history of life, the Cretaceous extinction, about 65 million years ago, which wiped out the dinosaurs and opened up an ecological niche for large mammals to evolve. Our designated minstrel, a science buff named Jonny Berliner, describes it this way in a song called “The Evolution of Man”:
One day a mighty meteor came down from out the sky,
And killed those nasty dinosaurs so the micey things could thrive,
Everything mammalian, grew bigger almost daily and...
Soon our furry ancestors were swinging in the trees...
We pause here to wait for the Marsupials. According to Dawkins we share a common ancestor with kangaroos, opossums and other pouched mammals approximately 80 million generations back. Presumably this relation was a small and unimpressive quadruped that rooted around in the dirt for insects—a seemingly unlikely candidate to supplant the giant reptiles that dominated the Triassic. But, Dawkins notes, those are often the species whose descendants inherit the earth. “It seems to be a rule,” he writes, “that large and specialised animals...don’t have a long term evolutionary future but belong to the 99 per cent of species destined for extinction.” Left unsaid is that “large and specialized animal” is a pretty good start on a description of Homo sapiens.
The Ancestor’s Trail attracts the sort of people who worry about not just the next generation but about the species that will inhabit the earth after we go extinct. That’s Jenord’s view. He is 50, with a degree in ecology, and a former wildlife ranger who is now a high-school science teacher and a member of his local humanist society, through which he recruited many of today’s participants—teachers, librarians, engineers and businessmen. On issues of belief they range from humanist through agnostic to atheist, and they seem familiar with the “New Atheist” literature. I achieve minor celebrity when I mention that I once spent three hours interviewing the late writer Christopher Hitchens (author of God Is Not Great) for a magazine profile.
“Oh! What was he like?” asks Ian Wallace, a ruggedly handsome apiarist who named his young son Darwin.
I was hoping not to be asked, because Hitchens and I met in his apartment over a bottle of whiskey and I have neither memory nor notes of anything he said. But that turns out only to add to the luster of the encounter.
“Wait till I tell my mates I met a guy who got pissed with Hitchens!” Wallace gushes.
A recurring theme in atheist writing is that in the competition of worldviews, science is at a disadvantage to religion, because it does not meet the universal human need for fellowship and the comfort of familiar ritual. In fact, Jenord got the idea for the Ancestor’s Trail after witnessing the famous Christian pilgrimage El Camino de Santiago de Compostela across northern Spain. It occurs to me that this evolution trek, now in its fourth year, might become a prototype for a nontheistic form of ritual—worship, even, of the process that guided the development of life on earth and gave rise to creatures that can commune over a bottle of—was it Jameson? I later mention this notion to Dawkins, who has described himself as agnostic about God “in the same way I am agnostic about the existence of fairies in my garden.” He dismisses the worship idea as rubbish. “I don’t think we need anything like that,” he says. “You don’t need an excuse to go walking in the woods.” He quickly adds, “I never actually thought anyone would want to do this. Although I’m delighted that they have.”
310 Million Years Ago: As we break for lunch, we are traversing slate and limestone hills roughly from the Carboniferous period, so the actual rocks beneath our feet correspond to where we are on our evolution timeline, give or take a mere 50 million years. Here we rendezvous with the Reptiles, who are wearing dinosaur masks, and we also encounter some actual reptiles, in the form of several palm-size tortoises, supplied by Eleanor Chubb, a breeder and enthusiast. She informs us that the British are extremely fond of reptile pets, which are now said to outnumber dogs on the isles.
One of the Reptiles, Rob Lambert, wears a leather collar studded with vaguely reptilian spikes, which I mistakenly assume is part of his costume. Actually, he wears it all the time, except at work, although in his job as a particle physicist he doesn’t believe his colleagues would care, or perhaps even notice. At dinner the previous night he sported a black leather necktie adorned with sharp steel talons. “I’m a big friend of the dinosaurs,” explains Lambert, who lives in Amsterdam and flew in for the weekend with his magenta-haired wife, Helen. “It’s humans I’m not so sure about.”
The fellow with the bushy gray beard, the frock coat and the broad-brimmed, flat-crowned black hat is a Welsh actor named Ioan Hefin, who has made a career out of portraying Alfred Russel Wallace, the great 19th-century Welsh naturalist who discovered the principle of natural selection independently of Darwin. It was Wallace’s famous letter to Darwin in 1858 that convinced the latter to finally publish the theory he’d been developing since the 1830s but kept out of the public eye, perhaps fearful of the devastating implications it held for the Christian worldview. “Some actors dream of doing Lear or Hamlet,” Hefin says modestly, “I just always wanted to be Wallace.”
Although Wallace’s theory was essentially the same as Darwin’s, and presented in London at the same time, Darwin is the most famous (and reviled) scientist of the 19th century, while Wallace is known mostly to students and specialists. “I always had a soft spot for Wallace myself,” says Jenord. “It’s a little bit of the British underdog thing, the question of fair play. And the fact that he achieved so much coming from an underprivileged background”—in contrast to Darwin’s country-gentry origins. A day before our hike, the Ancestor’s Trail group organized a conference in Bristol commemorating the centennial of Wallace’s death, intended in part to raise money for a Wallace statue in the Natural History Museum, a project that had languished for the last hundred years. (The sculpture was installed in November.) Dawkins spoke at the conference, and before a large rapt audience acknowledged Wallace as a co-discoverer of natural selection. But Dawkins also explained why Wallace never achieved Darwin’s eminence. “No one took notice of the Darwin and Wallace papers read to the Linnean Society in 1858,” he pointed out. Then, a year later, Darwin’s book, On the Origin of Species, “struck the Victorian solar plexus like a steam hammer,” Dawkins said. Indeed, in the first volume of Dawkins’ new memoir, An Appetite for Wonder: The Making of a Scientist, there are 28 references to Darwin—whose initials, CRD, Dawkins shares—but the name “Wallace” never appears.
590 Million Years Ago: The group is spreading out as the stronger walkers hit their stride and others tire. Jenord has carefully laid out a route that climbs gradually from an elevation of around 250 feet to about 1,200 and then ends at Kilve beach, famous for its fossils of ammonites, a spiral-shaped marine invertebrate from the Jurassic period, 146 million to 200 million years ago. At one juncture, where the descending path makes a right-angled turn, a few of the participants continue blithely straight downhill, requiring Jenord to run back and shepherd them onto the trail. “Oh, no, you don’t want to go that way,” he says genially. “That leads to extinction.”
On a ridge lined with heather, gorse and fernlike bracken, we meet up with the Protostomes, a category that includes the majority of species on earth, including mollusks, flatworms, roundworms and annelid worms, as well as the arthropods: crustaceans, spiders, centipedes and insects, among others. Standing in for this vast category of life are a half-dozen walkers with bobbing antennae on their heads. Ants.
We are now in deep evolutionary time, where biologists are piecing the tree of life from what evidence can be gleaned from DNA. Ahead of us are the jellyfish, and beyond them only plants and algae and single-celled organisms. The path descends steeply toward the Bristol Channel, and there we will end our journey where life began 3.5 billion years ago, in the warm slosh of the sea, whose salt still seasons our sweat. To greet us at the water’s edge, an artist named Victoria Gugenheim has painted a model’s body to resemble a labyrinthodont, a long-extinct amphibian that stands in the line of descent from fishes to terrestrial vertebrates. Gugenheim has a theory that art helped drive the evolution of the human brain as much or more so than hunting, which usually gets the credit.
And we have music. As we trudge through the pretty village of Kilve, we are met, again, by a brass band, honking and tooting us on our way to the water’s edge. A woman stops on her steps to watch us pass. “What are you celebrating?” she calls.
"Life!” we answer.