Gatun lake, the enormous midsection of the Panama Canal, sprawls for thirty-seven kilometers around peninsulas of land, between fragments of drowned mountains, and over the Continental Divide. Oceangoing vessels slice through the canal and shudder into steel locks that close and open almost silently. The lake's shoreline is wildly irregular, and its waters are as green as the sea.

Impenetrable forest flanks the canal. Toucans screech from low branches, and monkeys leap from tree to tree. Iridescent blue butterflies as large as teacup saucers flit along the shore. Inside the forest, a dark tangle of creeping vines and fringed palms battles to reach the sunlight. Here, where two continents meet and the waters of two vast oceans lap against the lake, lies a teeming cornucopia of life at its competitive extreme, a place like few others on Earth.

From a spot near the middle of Gatun Lake, opposite a deserted village called Frijoles, Barro Colorado Island rises steeply. Its muddy red banks appear jumbled, its interior black. Isolated by the rising waters of the Chagres River, which was dammed in 1910 to form the canal, Barro Colorado had been the highest point on the Loma de Palenquilla ridge. Now the ridge is gone, and Barro Colorado's peninsulas and uplifts sprawl over 1,564 hectares, or six square miles; its summit rises 119 meters above the lake's surface.

From where I stood on the deck of the island's launch as it chugged through the shipping channel, I didn't see Barro Colorado until we were nearly upon it. Then, just before the place where the canal arcs into Bohio Reach, I spotted several red and green channel markers leading into a small cove. A swimming raft floated there. Looking up, I caught a glimpse of tin-roofed dormitories set into the fringed hillside. Emerging from the background of green was a flight of steep concrete steps, which pulled my eye uphill to a graceful veranda and, behind that, to a peaked roof almost lost in the forest's lush canopy.

The low-lying clouds of early morning draped the thickly forested island, giving it the feel of a Chinese landscape painting. Then a small motorboat puttered up to a dock. A woman in camouflage pants tromped across a metal walkway. The lights flickered on in two low-slung buildings. The laboratory in the jungle came to life.

This wasn't my first visit to Barro Colorado. I had traveled to the island nearly ten years before, in 1990, with the much-lauded Harvard biologist Edward O. Wilson. He was there to collect Pheidole, the largest genus of ants in the New World; I was there to write about him for a magazine.

A hero to BCI's residents, Wilson was charming and erudite. He'd won two Pulitzer Prizes, for his writing on ants and on human nature, and one Crafoord Prize, the ecologist's equivalent of a Nobel. He'd ushered the subdiscipline of sociobiology into the mainstream, and now, in his sixties, he was lecturing world leaders on the value of conserving biodiversity.

By day, Wilson and I had walked the forest trails. He'd pointed out stingless bees and basilisks, foot-long lizards with craggy fins down their back and tail. He'd explained the intricate relationship between bruchid beetles and a large rodent called an agouti. “Get a load of that,” he would say effusively, without a trace of self-consciousness, as he stooped to examine a cryptically colored butterfly.

By night, we had sat around the table in the dining hall, the building with the peaked roof and veranda that overlooked the cove. Over plates of rice and beans a dozen scientists sparred and jousted. They slung statistics and tried to best one another with observations made in the rain forest. “I saw two howler monkeys copulating on Fairchild Trail this morning,” a serious-looking plant physiologist said. “I almost stepped on a juvie boa constrictor,” a bat researcher countered.

After dinner we drank Atlas beers and the scientists griped about how much money molecular biologists were taking from science budgets, leaving the zoologists, the organismal biologists, the ecologists, with nothing. Names were dropped, tenure decisions criticized. Outside, the jungle thrummed and pulsed; inside, ants streamed over a drop of grape jelly.

Most of the residents were male, with a bias toward entomology. One was studying jumping spiders, another was looking at the flight performance of migratory butterflies, another observed the foraging patterns among leaf-cutter ants. One scientist spent her days examining the teeth of dead anteaters; they offered clues to evolution, she said.

From my first walk with Wilson, the forest had intrigued me. But I found the island residents equally compelling. Like Wilson, they focused on subjects that had seemed, to me, hopelessly arcane. How do frogs produce their mating calls? How much water transpires from a tree? Unlike Wilson, many of the scientists did nothing to hide their ambition. They were often aggressive with one another, or else painfully shy. Many had little social grace. That was fine by me. After all, they lived in a jungle, and their struggle to survive, to use the phrase made popular by Darwin, was tuned to fever pitch.

My first visit to Barro Colorado was brief, but I was there long enough to see that its residents lived and breathed science through their every waking hour. Their language was data, their currency was scholarly publications, their religion was the creative forces of nature itself. I didn't understand a lot of what was going on, but the work seemed important to me, and noble. At the time, the word “biodiversity” was just beginning to enter the common parlance. Rain forests were going up in smoke, and disappearing with them were storehouses of knowledge and potential new drugs, foods, fuels, and fibers. Scientists like Wilson were preaching the gospel of conservation: every piece of the natural world, from microbes to pandas, matters. Caught up in the excitement of this place, I trusted that scientists like these would reveal, someday, exactly how.

When I got home from Panama, images of the rain forest stayed with me, as did the patter of the postdoctoral students in the dining hall and the roar of the insects outside my cabin door. Years passed. Worldwide, natural areas continued to deteriorate. What was the role of scientists now? At a time when so much was going wrong with the environment, fewer people were being trained to know the environment. There were fewer biologists who understood the relationships among whole, living organisms or recognized individual species. Science seemed ever more focused on molecular studies, on parsing genomes and analyzing the expression of proteins. Eventually, I wondered, were we going to lose touch with the world around us by being so fascinated by the world inside us?

And yet in this world made smaller and narrower by technology, researchers were still coming to BCI to make broad studies without thought of profits or patents. They were studying evolution in a forest, not in a test tube or a computer. It may sound hokey, but there were still scientists on BCI who studied nature for the pure joy of it. Their exuberance piqued my curiosity. And so, three months before my own wedding, I said goodbye to my fiancé and boarded a plane for Panama.

The island awoke at dawn with the desperate-sounding screams of a thousand howler monkeys, bellowing their territorial yawp. The toucans and parakeets and kiskadees were well up by now, ascreech and atwitter. Bands of coatimundi, their ringed tails held aloft, snuffled through the leaf litter of the lab clearing. In rubber sandals that slapped against the concrete walkways, the scientists slouched downhill toward breakfast.

I'd been here a day already, and I was eager to get into the forest. Alone, I climbed the concrete steps that led away from the lab clearing. Within the forest, the morning racket gradually settled to a low hum of birds, insects, and frogs. An anonymous creature obscured by the tangled understory let loose a sound like broken ceramics in a bag. A chicken-sized bird produced an eerie wail — like a finger circling the rim of a crystal glass.

Moving along the trail, I stepped over ants carrying bright green leaf fragments. I stared at a pattern of brown-dappled light that beamed across the forest floor. It slithered away when I approached — a five-foot boa constrictor with no taste for confrontation.

The forest was greenly dim. The air smelled of dampness, of earth, of mammals. A branch snapped above my head, but no pieces made it through the snarl of vines, saplings, and shrubs to reach the ground. I came upon a fig tree, its bark smooth and its trunk skirted with enormous buttresses. The renowned scientific traveler Henry Walter Bates, working his way through Amazonia in the middle of the nineteenth century, compared these buttress chambers to stalls in a stable, some of them large enough to hold a dozen people.

Woody vines called lianas looped over the forest floor like cursive writing run amok. Grasping neighbor trees with their tendrils, thorns, hooks, arboreal roots, and leader shoots, they hoisted themselves into the canopy, where they lounged over the treetops and sprawled for hundreds of meters. Their stems, meanwhile, grew as thick as many a temperate tree. Examining the fresh tips of one vine, I thought that if only I could sit still for two hours I'd certainly see them grow.

But it was too hot to stay in one place, and soon I moved on, turning from Wheeler Trail onto Barbour-Lathrop. A twenty-centimeter seedpod covered with thousands of tiny spikes caught my eye. A spider disguised as white rootlets lay flat against a tree trunk. A blue morpho with a fifteen-centimeter wingspan flopped by in the soggy air, headed downhill toward a sunlit creek. With its arresting coloration and outsize proportions, this butterfly seemed the quintessential symbol of biological weirdness spawned by the hothouse climate. Here things got large, even unseemly: flower petals the size of cake plates, beetles like grenades, leaves as long as coffee tables.

The morpho alit on a tree trunk, folded its wings, and instantly disappeared, its underwing coloration a perfect crypsis against the mottled bark. This was nature, I thought, at the height of her creative powers.

Charles Darwin knew intuitively that tropical forests were places of tremendous intricacy and energy. He and his cohort of scientific naturalists were awed by the beauty of the Neotropics, where they collected tens of thousands of species new to science. But they couldn't have guessed at the complete contents of the rain forest, and they had no idea of its value to humankind. Even now, more than a century later, the mechanisms of the rain forest still baffle, and impress, scientific thinkers.

Some of the best of them have worked on Barro Colorado Island. The laboratory on the island's northeastern shore has operated continuously since 1923, its backyard the most-studied tropical rain forest in the world. Barro Colorado is both a monument of nature and, perhaps more tellingly, a monument to nature — off- limits to the general public, virtually stateless. Sitting between two continents, it is populated by field researchers from around the world and administered by the Smithsonian Institution, which acts as a diplomatic mission to science.

The station was the brainchild of James Zetek, a U.S. Department of Agriculture entomologist who'd been working on mosquito control in the Canal Zone since 1909. Zetek, a Czech from Nebraska, had noted the ongoing destruction of the local watershed: land that had been forested was being logged and farmed for the simple reason that it was now, via the canal's labyrinthine shoreline, reachable.

Zetek took every opportunity to speak with scientists who passed through the Zone about setting aside land as a “natural park,” but it wasn't until March 1923 that he got lucky. He met up with William Morton Wheeler, a professor of economic entomology at Harvard's Bussey Institute for Research in Applied Biology, and took him by train to the tiny lakeside town of Frijoles, from which point a boatman ferried the men to Barro Colorado.

Wheeler spent just an hour on the island, but in a clearing of less than one acre he collected nineteen species of ants. Zetek took ten species of termites, and each of them took a dozen species of myrmecophiles and termitophiles. “Two new genera, one a beetle, very remarkable!” Wheeler would later write.

Zetek made a similar pitch to Thomas Barbour, the associate curator of reptiles and amphibians at Harvard's Museum of Comparative Zoology, who was also conducting research in Panama that month. Together they decided that BCI, the only large piece of relatively undisturbed virgin forest left in the Canal Zone, would make an ideal place to conduct biological research.

Seeking protection from settlers, hunting, and other human interference, Zetek presented his idea to the Canal Zone's governor, Jay Johnson Morrow, who received it warmly. With an alacrity unheard of in the modern conservation era, Morrow proclaimed the island a nature reserve on April 17, 1923. From this day on, settlers would decamp; any hunters who were found trespassing would be considered poachers.

Unfortunately, Morrow had no funding for the station, and neither did the U.S. government. The men who dreamed of a field station would have to build it themselves. Barbour had recently made a killing on the stock market and was willing to help out. David Fairchild, the U.S. Department of Agriculture's chief “plant explorer,” gave his own money (his wife was the daughter of Alexander Graham Bell) and raised even more from his socialite friends Allison Armour and Barbour Lathrop. Their money put up buildings and a track and engine to hoist supplies, by cart, up the 196 concrete steps between the lake and the clearing.

It was here that the laboratory rose. Facing northeast, the wood-frame building afforded excellent views out over the lake, toward the jumbled green hills in the middle distance and, on a clear day, on to the low spine of the Cordillera, the backbone of Panama's uplift.

On my second trip to the island I was happy to see the old lab still standing, though substantially reconfigured; it looked trim and neatly painted. I'd eaten in the downstairs dining room ten years before, but the building was now used as a visitor's center and a party hall. Since a wave of renovations in the early 1990s, everyone ate in a new building farther downslope. The scientists worked in air- conditioned labs near the lakeshore and slept in relatively insect- free dorms built of poured concrete.

Beyond the lab clearing, though, everything seemed the same — as ten years earlier, or a hundred. The island was still thickly forested, and there were still no roads or villages. Evidence of modernity was scant. History looped all around me in the fifty-nine- kilometer trail system.

Turning off Barbour-Lathrop, I was walking through time, along trails that formed an epic poem of the research station's, and of tropical biology's, history. Zetek, Wheeler, Barbour, Armour, Fairchild, Gross: these were the names of the men who built the station, who made its reputation. The dusty specimen jars of BCI's old herbarium and the abandoned monkey cages rusting along Allee Creek punctuated this history, reminders of the station's evolution from the days of pure plant-and-animal description through the advent of naturalistic studies of creatures in their native habitats.

Downhill, in the modern laboratories, gas analyzers and slides holding snippets of DNA pointed to the future. These new methods, in concert with the old, were shining light on the inner workings of the tropical forest — the most elaborate and complicated natural system on the planet, home to two-thirds of the approximately 4.5 million species alive on Earth today.

BCI is dissected by radial streams that flow, in the rainy season, down its steep ravines. The ubiquitous ridges and gullies can make for rough going. There isn't a sizeable section of level trail on the entire island, except for an area near its plateau, where I turned onto a trail named for Allison V. Armour.

A philanthropist, Armour liked being around scientists enough to shuttle them to research sites around the world on his yacht, the Utowana. He contributed tens of thousands of dollars to the field station during its early years and donated a launch, called the AVA, to the island.

I knew I was the first one down Armour that day because I had to break trail — bust up the thick, sticky webs of Nephila, a psychedelic giant. Nephila's body is about two and a half centimeters long, with iridescent green and red markings. Her eight legs are long, lacquer shiny, and delicately pointed. After blundering into several webs and wondering if the builder — who isn't actually dangerous — was now inside my T-shirt, I plucked a stick and walked like a conductor wielding a baton, with particular emphasis on the downbeat.

I began to notice the local tree bark. I had no hope of identifying anything. The leaves were usually too far up to see, or too entwined with other branches for me to tell which belonged to which. A mere fifty hectares at the top of the island contain more than 300 tree species, more than are found in all of North America above Mexico. The island itself has 1,369 species of vascular plants - - more than in all of Europe.

Most of BCI's trees have smooth bark, or bark mottled with shades of gray or brown. Some trees are ponderously columnar. Others, wrote Frank Chapman, an ornithologist who spent twelve consecutive dry seasons on the island, “suggest stripped athletes, with muscles and sinews swelling beneath their thin skins.”

Although the northeastern half of the island had been widely cut in the late nineteenth century, the “back side,” where I was now, contained trees more than a hundred years old on land that had been little disturbed for centuries. Many of these trees have large buttresses, which give them circumferences of more than fifty feet.

How old are these grand specimens? It is difficult to say. Without a distinct growing season, tropical trees lack growth rings. In general, they have shorter life spans than do their temperate cousins. They fall victim to pathogens and herbivores, they have shallow roots, and heavy winds and clinging vines often topple them.

For all that was known of Barro Colorado Island, for all the measuring, observing, comparing, and thinking over seventy-five years, the forest did not give up its mysteries easily, which was why it attracted a steady stream of investigators. While academics in the United States debated whether science had reached an end, whether all our great discoveries were behind us, researchers on Barro Colorado didn't seem to have heard the news. The island, home of the world's longest-running seminar on tropical biology, had never been busier.

In time I would learn to identify a fair number of plants, but for now they confused me. Like most nonscientist visitors, I was far more interested in BCI's animals. Isolated for centuries by rough terrain, thick jungle, and diseases that kept man at bay, then protected by Gatun Lake and legal decree, Barro Colorado nurtured some of the most diverse animal life of any tropical nature reserve.

In the months to come I would regularly spot squirrels, rats, peccaries, agoutis, coatimundi, deer, sloths, monkeys, tayras, anteaters, bats, iguanas, geckos, basilisks, crocodiles, and dozens and dozens of gaudy birds. If I had applied myself, I might have seen a tapir or an ocelot.

Early scientific visitors to the tropics had the thrill of naming thousands of creatures. Henry Walter Bates, for example, came out of the Amazon with 14,712 species, almost two-thirds of which were unknown to science. As we enter another millennium, the contents of the Neotropics, even a place as well traveled as BCI, are still being described.

I walked on, past a small metal sign marked AVA 4. It meant I was four hundred meters from the trail's beginning. All island trails are marked this way, every hundred meters, which makes it easy to find things and hard to get lost. Each of the island's fig trees is also marked and mapped, and atop the island's plateau, every stem larger than one centimeter in diameter at breast height (1.3 meters from the ground) wears an identifying number. Had everything on this island been examined and mapped? I wondered.

One day a few months on, I would find myself in an area of BCI that had no tags or flagging, no numbers or stakes or signage — a place where the hand of Science had yet to leave a mark. The area felt remote, silent. There were no trails, and I had to navigate by compass. No part of the island had ever felt so wild to me.

As a child, I took pleasure in imagining that I was the first person ever to walk the woods beyond my suburban house. As an adult, far from BCI's lab clearing, I easily conjured up that feeling once again. But the feeling didn't last. After twenty minutes of bushwhacking I spotted a plastic flag in the ground. My heart sank. Then I spotted a tree with a metal tag, then another and another.

With a pang of disappointment I realized that all here had been inventoried, that these acres were as studied as any others on the island. Someone within a few kilometers of me could name (and probably had) every plant in sight. Someone else could name all the vertebrates. As for the invertebrates, well, those descriptions were on their way. Entomologists had about a million species sussed — most of which occurred in the Tropics — with several million more just waiting to be described.

That science knew so much about tropical organisms was a good thing, to be sure. But I liked a little mystery in nature, a little unruliness, all the same. This idea — that there was something left to discover out there, whether the names of new organisms or the processes that allowed so many to coexist — would come to thrill me as the months went by. Now, near AVA 5, a small brown creature, sleek of fur and delicate of foot, scuttled across the path. It was an agouti, which looks like a rabbit crossed with a deer but is actually a rodent, a fact I was reminded of as it eyed me blandly and perched on its hind legs, squirrel-style, to gnaw on a large seed.

The unique fauna of Central America confused the earliest non- native explorers. Columbus reported seeing lions, stags, and gazelles here — creatures that sprang from an Old World mindset. John Lloyd Stephens, an American booster of a sea-level canal, saw alligators and heard both wolves and mountain cats, creatures of North America, on his 1840 journey through Nicaragua.

Hoping to find a dead animal, something I could examine close up, I walked on. Lizards scuttled through the dry leaf litter. Purple blossoms wafted onto the forest floor. Dull-colored understory birds pecked at insects. What kinds of lizards, flowers, birds? I had no idea. Alexander von Humboldt, when he first visited the Venezuelan rain forest in 1799, expressed his frustration at recognizing so little of this landscape: “We rush around like the demented; in the first three days we are unable to classify anything; we pick up one object, to throw it away for the next.”

Darwin and Bates, as well as Richard Spruce and Alfred Russel Wallace — nineteenth-century British naturalists inspired by von Humboldt's accounts of the Neotropics — felt similarly overwhelmed by the forest's abundance. Its beauty and complexity appealed to their aesthetic senses, but as scientists they yearned to classify. Compared to the temperate forests, the tropics had so much more of everything: more butterflies, more beetles, more yellow birds. Why, these naturalists asked, were there so many species? As Darwin put it, “What explains the riot?”

Rain forests, as everyone knows, are all about competition — tightly packed species scrambling for food and sex and light and turf. Organisms employ ingenious methods of outsmarting one another — crypsis and camouflage, chemical deterrents and chemical attractants. Parasites drive some bats to live as singles and the seeds of trees to grow wings, the better to escape the crowds that invite attack.

Yet for all this competition, different species live side by side, many depend on others for their very existence, and most owe their competitive edge to the constant pressure of their rivals. How did such systems evolve? Are there general principles that explain the maintenance of the forest's diversity? How do the forces of cooperation, or mutualism, measure up to those of competition? Increasingly, it's cooperation that scientists emphasize in their evolutionary studies.

Questions about the origin of species and the persistence of species stand at the heart of evolutionary and ecological studies today. The answers have value as basic research, and they are critical for conservation planning as well. Some trees, it turns out, are pivotal in maintaining a community of plants and animals, and their loss could cause a chain reaction of other losses.

Darwin's question, about the relative abundance of the tropics as compared to the temperate zone — a phenomenon known as the latitudinal diversity gradient — remains to this day one of biology's thorniest questions. Scientific thinkers over the decades have posited numerous theories, both complex and simple. Most of these existing theories are untestable, some contradict others, and not one is accepted as dogma. The gap in understanding left room for a young scientist I'd soon meet to puzzle out a new theory and introduce it in the marketplace of scientific ideas.

I meandered slowly through the wonderland of the island's western slope, the green light shifting and fading to gray as the afternoon wore on. The intermittent breeze carried a cornucopia of scents: wintergreen, sugar, skunk, monkey house, maple syrup, air freshener, sweat. Underfoot, twelve centimeters of leaf litter crackled. By the middle of the rainy season it would all be gone, the earth bare.

I hiked on, though paranoia dogged me. Did these leaves swarm with chiggers, and were they working their way into my socks? I was tempted to stop and investigate, but this was the first hike of my field season, and I was trying to set a standard of physical stoicism. At last I reached Armour's end, at the lake. But this was no beauty spot. The shoreline was boggy; the lake was picketed by white, eighty-year-old treetops, dead but still standing. It looked like a cemetery.

No breeze reached this desolate place, which evoked in me a sort of pre-canal jungle horror. It was just this situation that David McCullough described in The Path Between the Seas, his chronicle of the canal's creation: “All varieties of tropical fever and miasma were caused by ‘noxious vapors' released from the putrid vegetation and rank soil of the jungle. Any excessive disturbance of such ground, therefore, naturally meant the spread of disease in epidemic proportions.”

Contemplating the potential for miasma, I sat down on a handy rotted log, then almost immediately leapt up. The log was crawling with seed ticks the size of a pencil point. I spent twenty minutes plucking several hundred of them off my legs with a scrap of duct tape I found in my backpack. Then another ten minutes wrapping my duct tape in duct tape, so I could transport the tick ball back to the lab. What a magical place is a rain forest, I thought to myself.

The tropical rain forest, like the polar regions or the planet's great deserts, is largely a metaphorical landscape. In fiction, in art, and in poetry, it represents fecundity, sensuality, and wonderment. A hundred years ago, at the height of the tropics' scientific exploration, the rain forest's endless growing season and its diversity of plant and animal life implied to those coming out of the comparatively sterile north — with its limited roster of plants and animals, its orderly gardens, and its bleak weather — both a primeval loucheness and proof of a magnificent life force. Darwin called Brazil's rain forest a luxuriant hothouse, and one suspects he meant it in more ways than one.

The South American forests, undefaced by the hand of man, were “sublime,” Darwin said, a temple “filled with the varied productions of the God of Nature: — no one can stand in these solitudes unmoved, and not feel that there is more in man than the mere breath of his body.” Of his meanderings in the forest, he wrote in his journal, “I never experienced such intense delight.”

For travelers less scientific, the Paleo- and Neotropics represented a place to get lost, a heart of darkness within which the trappings of civilization could be forgotten. The setting was appropriate — dimly lit, uncatalogued, unmapped, and populated by lightly clad primitives. Bizarre life forms advertised their sexual fitness with gaudy colors and displays. Here, everything grew more rapidly: parasites lived on parasites, flowers lingered for months at a time. Decay, too, was quicker: mold, insects, and fungi pounced on the heels of death. Together, they made the renewal of life all the more swift.

Many European naturalists visited Central America in the seventeenth and eighteenth centuries, but none had the intellectual background to address scientific issues: Why were New and Old World organisms different, or similar? Even by the mid-nineteenth century, only a handful of people with a Western scientific perspective had entered the tropics. There was no uniform theory explaining how life on earth had evolved; the Amazon's biota was entirely unclassified. For men like Darwin, Bates, and Wallace (who visited South America but didn't make it to Central America), the field was wide open.

Their experiences in the tropics would become essential to these British naturalists' later formulations of evolutionary theory. Upon noting the wide dissemination of plant and animal species along an Amazon tributary, for example, Bates began to wonder how their seeds and eggs got around: “Unless it can be shown that these [species] may have migrated or been accidentally transported from one point to the other, we shall have to come to the strange conclusion that the same species had been created in two separate districts.” This idea would later come to be known as convergent evolution, which explains how unrelated organisms independently develop similar features in response to similar environmental challenges. Such traits include how to locomote, how to conserve water in a hot environment, or how to store energy.

Working in the Malay Archipelago, Wallace wrote in 1848: “There must be some other principle regulating the infinitely varied forms of animal life. It must strike every one, that the numbers of birds and insects of different groups, having scarcely any resemblance to each other, which yet feed on the same food and inhabit the same localities, cannot have been so differently constructed and adorned for that purpose alone.” In short, Wallace was asking why competition doesn't exclude all but the fittest creature from its niche. He was asking the eternal question: How do similar species coexist?

The nineteenth century both demonized the rain forest as a place of dank mystery, bad morals, and disease, and romanticized it as a garden of abundance and innocence. More recently, the rain forest has come to symbolize man's destruction of the planet. As goes the rain forest, according to this dictum, so go we.

Developing nations use their disappearing rain forests to gain geopolitical leverage; tribes indigenous to the rain forest play on First World ecoguilt to rally support for their threatened way of life. Environmental groups raise money off images of rain forest destruction; ecotourism operators lure well-heeled vacationers with images of its beauty and abundance. Here on BCI, doctoral candidates ignore the aesthetics and the politics of the forest in order to make of it a proving ground, a place to enact the research that leads to Ph.D.s, then jobs.

For those not living in a remote jungle, however, politics is hard to ignore. Every day comes word or image of a natural landscape in decline. We are living, as David Quammen has written, in one of the great soul-searching moments of human history. Never before has our fate, linked inextricably with the health of the planet, rested so surely in our own hands. Indeed, it is now the actions of human beings themselves, and not solely the blind mechanisms of natural selection and genetic drift, that are altering the terms of survival for every species on the planet.

The current extinction crisis — in which an estimated one- third of one percent of all bird and mammal species go extinct each year — is on course to rival that of the Big Five, of the Ordovician, the Devonian, the Permian, the Triassic, and the Cretaceous. How we respond to species extinction, and to massive habitat loss, global warming, and unchecked air and water pollution, will likely define the new century.

It was an exciting time to be among scientists, among field biologists working at ground zero. I had come to Panama to see what that work looked like, and how studies so seemingly arcane could possibly shape decisions yet to be made. I had come here, also, because nature had enthralled and confounded me from an early age and because here were people who could decipher it.

As I walked back to the lab from Armour Trail with tick ball in hand, my enthusiasm for this place remained undimmed. I was going to see an intact rain forest, through the eyes of experts, before all the rain forests were gone.

Copyright © 2001 by Elizabeth Royte. Reprinted by permission of Houghton Mifflin Company.