“The great God that formed all things Both rewardeth the fool, and rewardeth transgressors.” Each year the habits of the dirty dozen on this island handicap the flock and increase the odds that the whole flock will die. Cactus finches did go extinct earlier in this century on the uninhabited island of Pinzón, whose name is Spanish for finch. The cactus finches of Pinzón may have cheated themselves off the face of the earth.
DARWIN HIMSELF was (at least sometimes) an optimist. In the Descent of Man he wrote,
The Simiadae then branched off into two great stems, the New World Monkeys and Old World Monkeys; and from the latter at a remote period, Man, the wonder and the glory of the universe, proceeded.
He also wrote,
Progress has been much more general than retrogression.
Maybe Darwin was right about progress, and his descendants the G.O.D. specialists are right. Maybe the Generation of Diversity will outrace the Generation of Destruction. In the long run we may yet prove to be more children of light than children of darkness, despite the tinny hubris of the acronym G.O.D.
On the surface of the earth, on the surface of the backs of our hands, there are ropy loops of DNA in every cell, a changing galaxy of atoms in every strand of DNA, and views that bring a sense of origins as ultimate as the Big Bang. There is nothing more absorbing than to look around at trees, bare stubbly fields, a big black turkey culture wobbling overhead, from a winding strip of asphalt, at 60 miles per hour, and reflect that all this living scene is in motion too, in ways we can now begin to see. The branching of the branches of the tree of life—including our own branch—all this branching is going on right now, everywhere, although it is hidden from our view like stars at noon.
We have watched the animals around us from the beginning, each generation learning from the generation before, so that each sees more than the one before—as in these islands, where the first voyager to write about the birds said they showed neither novelty nor beauty, and where Darwin himself declared it impossible to watch the species of ground finches and tell them apart. Now these creatures’ evolution is the best known and the best watched on the whole of the planet, and they teach us what is going on in all the rest.
This is what we do best. We add to what was learned before, raising the old questions again and again, lifting them if we can toward higher and higher ground, and ourselves with them. Why are there so many kinds of animals, and why are we among them? Probably we have been asking these questions ever since we lived in caves—when it was still the common experience of our kind to stand alone on a cliff’s rim and survey a wilderness of animals, feeling kinship in difference, difference in kinship, our eyes watchful in their large orbits, our arms outspread. The questions were born then, as we stared down, or looked up at the sky, turning to follow the turning flocks, revolving our heads on our featherless shoulders: high above the plains of our first hours, winged only with the questions.
Epilogue
God and the Galápagos
Nature is the art of God.
—SIR THOMAS BROWNE,
Religio Medici,
1642
Have we any right to assume that the Creator works by intellectual powers like those of man?
—CHARLES DARWIN,
Origin of Species
It is March 1993 on Daphne Major. The craterlet is filling up with water. Boobies are swimming around in it like ducks. The paths are covered with grass and flowers—more grass and flowers than Rosemary and Peter have ever seen on the island. If it were not for the cactus, the Grants would almost think the Galápagos had gone adrift, true to their old name, Las Encantadas, the Enchanted Islands, and wandered into the Temperate Zone.
Only a few years ago the Grants could walk all the way around the rim of the main crater and not see a single finch. They couldn’t do that now. They are tripping over them now. The birds are incredibly bold too. “Do you think they’ve got tame, or are there just more of them?” Rosemary asks Peter. All day, Darwin’s finches fly up from the lava and perch on their shoulders. They come zipping in and land on Peter’s head.
Last year was a Niño. The year before that was almost a Niño, but then it fizzled. This year is even wetter than last year. “A string of three extremely wet years,” says Peter. “We have never seen anything like this. It is unprecedented in our experience.”
“I don’t know what they are saying anywhere else,” says Rosemary, “but on Daphne, this is a Niño!”
That is one of their catchwords this season, as the rain falls and falls: “I don’t care what they’re saying. It’s a Niño!”
This is their twenty-first year on the islands. When Peter and Rosemary first came here they were still in their thirties; now they are almost in their sixties. They had been dreading the return of El Niño: they wondered if they would be able to band all those birds. Now they are proving to themselves that they can still do it, alone on the island, with no assistants, for the second year in a row. But Peter’s beard has lost the last trace of auburn. The top of his head presents a somewhat larger landing zone. If they get back to Princeton this year, his friends will be shocked how thin he looks.
When rocks rattle and roll underfoot, they reverberate. Otherwise there is no sound but the wind in their ears and bird cries nearby and far, far down in the crater. “We have more birds breeding on the island this year than any other,” says Peter. “Except possibly 1984.”
The first rogue that Rosemary trapped on the north rim, two Januarys ago, is dead now. The body was never found. But Rosemary’s second catch that morning, 5608 (the Princeton bird, orange-over-black, born in the great Niño of 1983), is ten years old. Not only that, this year he was one of the first to breed. “5608 is in good health,” Peter says. “Got off to a flying start. Also, do you remember 2666? He turned up again this year. He’s the oldest fortis we have on record. That pushes the maximum life-span of fortis to fifteen years, which is really quite remarkable.”
“2666 bred this year,” says Rosemary.
“Hmmm,” says Peter, in comfortable agreement. “Still going strong.” He is surprised the old black cocks like 5608 and 2666 can find mates. Some of these birds wear their crowns half-bald rolling rocks around in the droughts, and then the bald spots grow back with brown patches. “I wouldn’t, if I were a female, mate with one of those,” he says.
“And they get clobbered by younger males,” Rosemary says.
“But then, look at me,” says Peter.
THIS YEAR A poll will show that nearly half the citizens of the United States do not believe in evolution. Instead they believe that life was created by God in something like its present form, within the past ten thousand years.
The power of selection, as seen in the skulls of pigeons. The common rock pigeon (A) has produced forms as various as the short-faced tumbler (B), the English carrier (C), and the Bagadotten carrier (D). From Charles Darwin, The Variation of Animals and Plants under Domestication.
The Smithsonian Institution
“People talk about Creationism,” says Dolph Schluter. “We can actually see Creation at work. We might ask the Creationists to demonstrate similar principles at work.”
“They have the appearance of closed minds,” Peter Grant says. “I don’t often meet fundamentalists, and I don’t go out of my way to challenge them. I think they are closed in that respect.”
John Endler, the guppy watcher, does not like talking with Creationists either. “I avoid it,” he says. “It’s really a waste of time. Not long ago on an airplane I talked for an hour with someone about what I do, and never once mentioned the word evolution. It’s very easy to do, you know. Darwin himself doesn’t use the word evolution in the whole of the Origin. You just talk about what happens, and how you can study what happens: changes over many generations. It might be interesting to try to write a book that way now: don’t use the word evolution until the very last page.
“Anyway, the whole time on the plane, my fellow passenger was growing more
and more excited. ‘What a neat idea! What a neat idea!’ Finally, as the plane was landing, I told him this neat idea is called evolution. He turned purple.”
“I’ve done exactly the same thing—and never let on it was evolution—and got exactly the same response,” says Rosemary. “I described our work on Daphne to a Jehovah’s Witness. And he followed along, and said, ‘Oh, how fascinating.’ ”
“Asked intelligent questions,” says Peter.
“And I never plucked up enough courage to say, ‘Well, you know, what all this means.…’ ”
Darwin, of course, was surrounded by Creationists too, including some of his greatest friends and mentors. Lyell, the geologist, after visiting Darwin’s pigeon coop, argued that however animals might or might not have been created, surely human beings were designed by the intervening hand of God. But Darwin asked if Lyell could believe that “the shape of my nose was designed.” If Lyell did think so, Darwin said, “I have nothing more to say.” If not, seeing what breeders had accomplished by selecting slight variations in the nasal bones of pigeons, why should our own beaks have needed anything more? Selection can make a beak; selection can make a nose.
“If anything is designed, certainly man must be,” Darwin wrote to another devout friend, the botanist Asa Gray. “One’s ‘inner consciousness’ (although a false guide) tells one so; yet I cannot admit that man’s rudimentary mammae, bladder drained as if he went on all four legs, and pug-nose were designed. If I was to say I believed this, I should believe in the same incredible manner as the orthodox believe the Trinity in Unity. You say that you are in a haze; I am in thick mud; the orthodox would say in fetid, abominable mud; yet I cannot keep out of the question, My dear Gray, I have written a deal of nonsense.”
Once it seemed logical to believe that God shepherds the planets around and around the sun. Regular orbits were said to be proof of the existence of God, a celestial argument from design. Astronomers imagined an invisible hand in constant attendance, pushing and rolling each world through the sky. This vision no longer seemed compelling after Galileo and Newton discovered the celestial laws of motion (consider, for instance, inertia).
Darwin discovered laws of terrestrial motion as simple and universal as the physicists’. For Darwin it was no longer necessary to assume that God’s hand had shepherded each line of life individually into being and molded it like clay. Paley’s argument from design collapsed. But beyond this, Darwin admitted ignorance.
“I feel most deeply that the whole subject is too profound for the human intellect,” Darwin wrote Asa Gray. “A dog might as well speculate on the mind of Newton. Let each man hope and believe what he can.”
TREVOR PRICE IS watching warblers in Siberia. (“Siberia is really opening up,” he says.) Lisle Gibbs is studying the DNA of cuckoos and cowbirds; Peter Boag the DNA of Darwin’s finches; and Laurene Ratcliffe the songs of sparrows, chickadees, and red-winged blackbirds.
For Dolph Schluter several ages have passed since he was watching finches on Pinta, listening with headphones to the Clash. Now he is watching fish in tanks and listening to La Traviata. He spends whole days with the sticklebacks in his lab and out on Paxton Lake. When he filled the new evolution ponds on campus, not long ago, he popped the cork of a bottle of Veuve Clicquot. “We plan to watch for twenty years,” he says, “or whichever senesces first, me or the experimental ponds.”
Ars longa, vita brevis. A life turns out to be a very short time. Dolph sometimes thinks of his hero, David Lack. “This is just a rumor that he said this,” Dolph says. “I heard it second- or third-hand—I’ve never seen it written up—but it was concerning the Great Tits of Oxford.” Someone asks Lack a question about the tits in Wytham Woods. “ ‘Well, I can’t answer that question,’ Lack says, ‘because I have only seventeen years’ data.’
“That doesn’t surprise me any more. I thought it was hilarious when I started grad school, but it’s pretty obvious to me now.”
On Daphne, Peter and Rosemary are now preoccupied with birds in the 18,700s. “What was 18,717 doing yesterday?” Soon they will be in the 18,800s. By the end of this spring, the Grants will have seen two dozen generations of finches hatch and die on the sides of the old bowl, their crater island, which the younger finch watchers used to call “the biggest ashtray in the world.” The Grants will be able to measure the powerful winds of selection that have blown across those two dozen generations, shaping the wings, legs, and beaks of the birds. But what are two dozen generations in the Galápagos? Daphne Major, a young rock as rocks go, is almost a million years old. It is the cinerarium of innumerable generations. A thousand ages in this place are like an evening gone. And the trail of the generations extends out of sight, both behind and ahead, like a line of flying birds that crosses the sky from horizon to horizon, or like the zephyrs that the Grants can see from the island’s rim on the calmest days, brushing the face of the sea.
From every line of living things, not only the birds but also every plant and animal, the same line of generations extends from horizon to horizon, “without ever stopping,” as in the pitying words of the Buddhist scripture: “Over and over again they are born, they age, die, pass on to a new life, and are reborn!”
Our own journey has not been tried before. No other creature has traveled so far along this line. No one knows what paths still stand open, if we manage to travel a little farther yet. The long columns of code in the Grants’ waterproof notebooks look random, formless, chaotic, like the lava. Only when the Grants take a step back from the numbers, only months or years from now, will the latest patterns emerge, the special providence in the fall of this spring’s sparrows.
The original meaning of the word evolution—the unrolling of a scroll—suggested a metamorphosis, as of moths or beetles or butterflies. But the insects’ metamorphosis has a conclusion, a finished adult form. The Darwinian view of evolution shows that the unrolling scroll is always being written, inscribed as it unrolls. The letters are composed by the hand of the moment, by the circumstances of the day itself. We are not completed as we stand, this is not our final stage. There can be no finished form for us or for anything else alive, any thing that travels from generation to generation. The Book of Life is still being written. The end of the story is not predestined. Our evolution continues. Like Belshazzar, when we look around us now we can almost see “the part of the hand that writes.”
WHEN THE ANCESTORS of Darwin’s finches landed here, these islands were new. They may have been the first living things to try the strange fruits of the islands and pick up the seeds from the lava; the first to perch in the half-naked bushes; the first to sleep, beak under wing, in the cactus trees.
A woodpecker finch becomes possible only on an island without a woodpecker, a warbler finch only without a warbler. A flower-browsing finch becomes possible where there are no bees and hummingbirds—and on islands where bees have now invaded, many of Darwin’s finches have given back the flowers. Many paths lay open when the finches first arrived, and the smallest flights and trials of their descendants were rewarded. That is why they have traveled in more directions than any other creatures on the islands, that is why they have evolved farther and faster than any other creatures: because they got here early.
Our own line is now radiating farther, faster, and in more directions than any other single species in the history of the planet—and for a similar reason. We are the first creatures to arrive in the strange territory we now occupy. We stumbled into our new niche before any other creatures on the planet. We discovered it.
“There came a flocke of birds into Cornwall, about Harvest season, in bignesse not much exceeding a sparrow, which made a foule spoyle of the apples,” wrote Richard Carew in 1602. “Their bills were thwarted crosswise at the end, and with these they would cut an apple in two at one snap, eating onely the kernels.” Like a sudden flock of birds, our wings fill the land. We hold all the fruits of the planet in our beaks.
Chimpanzees in the last of the African
rain forests are teaching their children how to crack nuts with stones. They are taking the kinds of halting, modest steps that might, if favored, if selected for many generations, carry them on a path toward something like our niche. Watching them, human observers notice striking variations in intelligence from individual to individual. Where there is genetic variation, there is room for selection and evolution. Probably in every line of primates there are a few, like Imo on her island, who could lead their kind in our direction. But at the moment of course that path is blocked. The thinking niche is taken, at least for the moment.
Possession, as we say, is nine-tenths of the law. This rule applies to all life on earth. Before life began, our planet was like the Galápagos Islands before the arrival of the first seeds: newly cooled, newly hardened, and vacant. The first molecules that could make copies of themselves could grow at their own pace. A molecule that duplicated itself erratically, budding off carbon copies with individual variations, could grow faster and faster and sweep the seas, infiltrating myriad cupped coasts and cracked ocean beds, taking off in new directions everywhere. All paths lay open to those changelings; the path of paths lay open. The molecule that began the journey had the form of a helix.
Biochemists can now make primitive self-replicating molecules in computer models and synthesize them in the laboratory. Some of the new designs are based on the helix, and some are hopeful molecules as fanciful as Darwin’s pouters, laughers, and fantails. This is a new kind of artificial selection, selection for life itself.
The Beak of the Finch: A Story of Evolution in Our Time Page 35
