Excerpts

PART I Isostichopus fuscus LEARNING TO SEE 1 A school of needlefish parts to stream around me, and I find myself momentarily among the silver traces of a comet shower. I move to join them, but they accelerate and dissolve into open water, leaving me to stare at the luminous, molten mirror that is the underside of the ocean's surface. Veronica taps my arm--a signal that says both look at that and be right back --as she slips from the roiled layer of silver and descends swiftly, like a being born underwater. Her skindiver's fins form a single broad fluke, which propels her neoprene form sinuously toward the rocky bottom. Bright bubbles, escaping her snorkel, wobble urgently back to the air above. A thousand times I have seen her descend like this, yet still I find myself wondering if, this time, she might go too deep, or stay too long. Here, mercifully, the seafloor is only twenty feet down--a depth at which the plunging chutes of sunlight are just converging to their vanishing point. As she approaches the rocks, Veronica twists, glides to a supine and weightless pause, and gazes up at the students who float beside me here at the surface. She seems to be pointing at something on the seafloor. Allie, the student to my right, turns to look at me. Inside the partial shade of her dive mask, her eyes are hard to read: They look puzzled, a little concerned. She is probably just wondering why Veronica wants them to notice what appears to be a mud-brown lump of sea muck. Though it also seems possible that Allie has already perceived Veronica's tendencies underwater--the strange private gravity that seems to draw her to depth--and she is now asking, in her gentle way, whether something should perhaps be done to bring Veronica back to the surface. I take several long breaths, saturating my blood with oxygen and preparing to dive, but just as I draw my last, deep dose of air, Veronica finally relents. She places her hand gently around the nondescript mound and pulls it from the rocks, holding it as one might hold a soft loaf of bread. Arriving among us, Veronica holds out her hand, upon which rests her inert quarry. What was mud-colored below is now--in this bright, shallow water--more of a yellow ocher, and it is studded with pale tubercles that are almost the color of lemon drops. The skin, stretched taut over the knobby body, appears thin and mucosal, making the thing look terribly exposed, like a bodily organ drawn by the hand of a surgeon into the sudden brightness of the operating theater. The students--there are five of them here--draw in around Veronica's palm, peering intently through their panes of tempered glass. They seem transfixed, certain that Veronica's plunge must have been for something thrilling, and yet I know their patience can be short, especially this early in the trip, when everything around them feels new. And so, as the thing on Veronica's palm waits us out, stolid as a piece of earth, I begin to worry that the students will soon lose interest, and miss what Veronica wants them to see. Just when I think they may be eyeing one another through their personal portholes--wondering, perhaps, if it would be rude to resume their search for colorful fish--the lump trembles, inches forward along Veronica's palm. Suddenly it is less vegetable than animal, and the students pull back apprehensively. But as the circle of masks starts to widen, Veronica's free hand catches Allie by the wrist. Veronica is wise, I think, to choose Allie, because there are others who might not be so trusting. Carefully, she opens Allie's palm and holds it beside her own. As the knobby creature slides from one hand to the other, Allie's eyes widen and she speaks into her snorkel--an incomprehensible but richly expressive string of syllables. For a moment, she seems frozen. But even in her astonishment, she looks to the other students. She takes the hand of the young man floating beside her, opens his palm, and holds it next to her own. The animal slides over obligingly, and as it does, Cameron explores the creature's back with his other hand. Cameron's hands look muscular, well-worn, and they sometimes move in unusual ways: the fingers seem to explore independently, executing many minor adjustments, as if they were navigating the neck of a string instrument. These hands have learned to perceive more than other hands, because Cameron cannot see. He is blind. And as his fingers creep across the animal's back, investigating, it becomes clear that they are following a pattern: the yellow warts, which at first seemed to be scattered more or less randomly, are in fact arranged--loosely, but nonetheless perceptibly--into two rows. I have never noticed this rough regularity, but now that I see it, I suspect it might be meaningful: I suspect, in fact, that those two haphazard rows are clues to a deep connection--an invisible but very real thread that links the ugly animal on Cameron's hand to far more beautiful creatures we've seen this morning. Just moments before her plunge, Veronica pointed us to a sun star, Heliaster kubiniji , a pink-and-green starfish in the unmistakable shape of a sunflower. And before that, we all hovered in admiration over the crown sea urchin, Centrostephanus coronatus , which is a sphere of long and slender spines, each one perfectly black but for the occasional sharp wave of blue light that races from tip to base. To describe these scattered pulses to Cameron, Allie said it looked "like an alien's brain." After Heliaster kubiniji and Centrostephanus coronatus , even the name of the animal now sliding across Cameron's hand rings a little prosaic. It is Isostichopus fuscus , the brown sea cucumber, and one would not readily assume that it has much in common with those other, much lovelier animals. Yet that is precisely what Cameron's subtle touch has just revealed: those messy lines of tubercles, I now realize, are among the attributes that place the brown cucumber firmly in the broad alliance of animals known as phylum Echinodermata. And who else should number among the echinoderms but the sea stars and urchins. All of these creatures, from ugly I. fuscus to brilliant C. coronatus , are the descendants of a single ancient species: an ur-echinoderm that inhabited the ocean 520 million years ago. And because that ur-echinoderm, in its own time on earth, underwent several extraordinary modifications--we could even call them innovations--we now find mementos of those changes in every single one of the creature's descendants. In fact, those vague rows of bumps just now detected by Cameron's hands are but a faint reminder of the ur-echinoderm's most fundamental innovation. But exactly what that innovation was, and how it later became a trace so obscure it took Cameron's touch to disclose--these are questions I should raise later, when we're back at the field station. Because right now, Veronica seems to have a plan of her own; she has just lifted her head from the water, letting her snorkel dangle by her face, and the rest of us now follow her lead. "Cameron," she says, "do you feel it attaching to your hand?" "Yeah, totally," he responds. Cameron grew up in a small town outside of Santa Barbara, California, and he talks like a surfer. "It's got those wicked little suckers," he continues, "just like the starfish." " Exactly ," Veronica says, clearly pleased with his suggestion. "Sea stars and cucumbers both have tube feet." As Veronica begins to explain how these ingenious little devices operate, Cameron allows the cucumber to creep back to Allie, who then takes the hand of another student. It's Chris, a quietly confident young man who may already know much of what Veronica is explaining. Chris has spent a semester at a marine biological laboratory, a month on an oceanographic research vessel, and, judging from his comfort in the water, a lot of time diving. As I talked with him during our long drive down the Baja Peninsula, Chris seemed strangely familiar, as if I knew him from somewhere. But it wasn't until we arrived at our destination, the small town of Bahía de los Ángeles, that I finally understood: the only people I'd ever met who possessed this calm composure--not arrogance, really, but equanimity--were the more formidable patriarchs here in Bahía. That Chris shares this trait is perhaps not entirely coincidence. His father is Mexican, and Chris spent part of his childhood in a picturesque village not far from Mexico City. The student floating beside Chris, Anoop Prakash, appears less comfortable in the water. In fact, he seems to be expending a tremendous amount of energy just to remain upright, and occasionally his fin flails out and whacks Chris in the legs. Despite these occasional assaults, the transfer of the cucumber from Allie to Chris goes smoothly, and Chris is now placing one hand in front of the other to make a kind of treadmill for the animal. Even with our faces above water, and the cucumber just below the surface, we can see that as it slides forward, its front seems to dab back and forth laterally, as if it were exploring the curious new terrain. The end of this treadmill ride, I'm afraid, will be Anoop's hand, and the thought of that unsteady platform makes me more than a little anxious--for the animal and Anoop alike. I assume Veronica too is monitoring Anoop's buoyancy, because his safety in the Vermilion Sea was the subject of some debate when we first reviewed applications for our field course. Anoop had approached us after the Baja info session, an informal presentation that Veronica and I offer for prospective students. As soon as the presentation had ended, he unfolded himself from his writing desk--he is tall for a South Indian, about six foot one--and in three gangly steps, he arrived at the front of the room. With a black goatee and wire-rimmed glasses that gleamed silver against his chestnut skin, he looked quite scholarly. And because the lenses over his eyes appeared somewhat too small--as though they could possibly clarify only what lay straight ahead, leaving the periphery in a blur--he also looked intensely focused. Fixing his narrowly tunneled view on Veronica, he said, "Dr. Volny, I'd like to ask what endemic species of salt-tolerant plants are found around the research station." Usually, students ask if we might really see a whale shark, or if the dolphin are there every year, or if it's truly so hot as we say it is. They do not, in general, ask about endemic salt-tolerant plants, and it took Veronica a moment to gather her answer. Later, when Veronica and I were laughing about the question, she seemed charmed by it, but she was also earnestly concerned that Anoop's sheer focus might compromise a more general awareness of his surroundings. "He'll step on a scorpion," she said. The students' written applications arrived two weeks later, and Anoop's was fabulously impressive. As I read certain sections to Veronica, she said, "You're making this up!" and grabbed the page from my hands. But I hadn't made it up. Besides the independent research in yeast genetics and a concentration in philosophy of science, there were graduate seminars on Marcel Proust and Ludwig Feuerbach, in which Anoop, a sophomore undergraduate, had earned perfect grades. But there were also a few sentences that Veronica referred to as "warning signs." In response to the simple question Can you swim? Anoop had written, Last time I checked, I was competent in breast stroke, Australian crawl, back stroke, and side stroke --a response that Veronica deemed suspicious for its very thoroughness. "He won't step on a scorpion," she said. "Because he'll sink first." In the end, I argued we simply had to take Anoop; his academic record--not to mention his devotion to salt-tolerant plants--left us no choice. Veronica consented, but added, "He's on your watch." And now I do watch--quite closely--as Anoop's hands rise and open to form the animal's next platform. Without his arms for paddling, he drops slightly: his chin lowers into the water, and he tilts his head back to keep his mouth above the wavelets. Tube feet, Veronica's been explaining, are the only outward sign of an internal system possessed by all echinoderms--sea cucumbers, urchins, sea lilies, sand dollars, brittlestars, and, as Cameron sensed, sea stars. The bodies of these animals are piped with a network of tubes, and when an echinoderm decides to move, water flows to the appropriate plumbing, creating hydraulic pressure. Each one of those hundreds of tube feet on an echinoderm's underside is the continuation of an internal pipe. When a foot needs to take a step, a small ampule inside the animal contracts, driving water into the tube and extending it until it touches the surface below--in this case, a student's palm. What feels like a miniature suction cup--or, as Cameron put it, a wicked little sucker--is in fact something stranger: As the little foot makes contact with the surface, it secretes a kind of quick-dry superglue, fastening it to its substrate. And when it is ready to let go, the foot secretes a fast-acting antidote to its own adhesive. Having crept from Allie to Cameron, back to Allie, and on to Chris and Anoop, the cucumber now seems to have reached something of a cul de sac, and I wonder whether any of the other students are growing impatient with Anoop. I don't think he intends to monopolize the sensation of tube feet on the palm; it's just that he's fully absorbed in keeping his head above water and his hands relatively steady. Rafe, the only student in our floating circle who has not yet handled the animal, seems to be sidling closer to Anoop, awaiting the transfer, though he is held at bay by Anoop's erratic kicks. Ever since he introduced himself at the Baja info session, Rafe has made me uneasy, because his self-assurance sometimes verges on blithe overconfidence. Veronica had asked everyone at the meeting to say a word about themselves, and most students seemed to blush and hurry through rather self-effacingly. But Rafe spoke slowly, with striking nonchalance. In his thick Australian accent, he said, "My name is Kurtis Rafe, but you can call me Rafe. My major is chemistry, but I'm taking a lot of theoretical physics as well." And when he said, serenely, "I'm applying 'cause I think it'd be ace to swim with sharks," the room broke into laughter, expelling its awkward tension, and Rafe sat back, smiling slightly. Even here in Baja, he keeps his long blond hair nicely combed, pulled back in a tidy ponytail, and he wears a small but thick gold hoop in one ear. Evidently, Veronica is not as concerned as I am about Rafe's looming encroachment; ignoring him, she says she wants to show the students something very strange about the echinoderms. And just from the way she says "very strange"--as if she were some sort of haruspex, preparing to astonish her small audience--I suddenly know what's coming, though I can hardly believe she's really going to do it with the creature resting on Anoop's hands. The first time Veronica took me diving in these waters, seven years ago, she found a brown cucumber. She placed the animal on my open palm, and when it began to creep forward, she gently pressed a finger against its knobby back. Almost instantly, the animal contracted, like a biceps balling up in tension. I pressed it with my own finger--it was as hard as a billiard ball--and I widened my eyes and shook my head in underwater communication of astonishment. But Veronica held up a finger, as if to say, "Just wait, there's more." She began to rub the animal's back, as though she were polishing its hardened surface. At first nothing happened; the billiard ball rested hard and compact in my hand. But then, with the abruptness of a dropped egg hitting the kitchen floor, the animal changed--it seemed to melt and began to ooze over the edges of my palm. In alarm I tried to hold the creature together, cupping it now in both palms, but the substance seemed to be seeping between my hands, and all I could do was hold still and hope that whatever was digesting the animal would not start working on me as well. Before I could even know whether my hands felt pain, the sludge had slipped from them and was pouring itself into a crevice in the rocks below. An hour later, I stood alone in the airless heat of the field station library, reading from a zoology text I had just slid off the shelf: The degree of change in the rigidity of mutable connective tissue is almost as great as that of ice to water. Indeed, people who have firsthand experience of echinoderm tissues passing from rigid to flexible states liken the transition to liquification. Liquefaction--ice to water--seemed exactly right. What was surprising, however, was that this mutable connective tissue is made almost entirely of the protein collagen. That seemed odd, almost disturbing, because the very same protein composes our own cartilage--the firm stuff of spinal disks, as well as noses. As I read this strange new fact, registering it slowly in the stifling heat, my fingers rose involuntarily to check on my nose. What this tells us, first of all, is that collagen is an old molecule. It must have evolved even before the ur-echinoderm branched off from our own phylum's ancestor, the ur-chordate; otherwise, we and the cucumber would not both have it. But once those ancient species had separated, and each was following its own evolutionary path, the ur-echinoderm must have hit upon some extraordinary innovations in the construction of tissue from collagen, because all the echinoderms, from elegant C. coronatus to homely I. fuscus , are able to go billiard-ball-hard one moment and pudding-soft the next. But what was it, exactly, that the ur-echinoderm discovered? How does a creature freeze or melt its own tissue at will? Collagen forms a rigid substance when millions of individual molecules gather into a thick fiber: imagine winding together twist-ties until they made something like a suspension bridge cable. Our own collagen is permanently wound into cable, such that our noses do not suddenly melt. But echinoderm collagen, by contrast, can suddenly disassemble, allowing the cable to relax and fall apart into so many millions of twist-ties. More fantastically, the twist-ties can then reassemble, linking up once again into cable. The mysterious substance that triggers this change is yet to be isolated in a lab, but we know it's a protein, and we know it's secreted by cells that are embedded in the mutable tissue. At the moment, however, the more pressing mystery is why Veronica would take Anoop, of all people, as her volunteer for a magic trick with mutable connective tissue. Given that we will try this only once in our two-week course--Veronica will surely ask the students not to repeat it, because it must take a toll on the cucumber--I don't see why she would make Anoop the one whose nerves will be tested. Does she think his excitability will enhance the shock of transformation? Or has she really put him on my watch, allowing herself to forget her own warnings? In any case, when she places her snorkel in her mouth and puts her face in the water, all of us follow suit, except Anoop: with the animal stranded on his trembling hands, he is unable to replace his snorkel, and is left alone above water while everyone watches his hands below. Through my half-submerged mask, I keep a watchful eye on Anoop's face. At first he looks somewhat resigned, like a surgical patient separated from the doctors' work by a curtain across his chest. But a second later, he whips his head suddenly to the side, trying to catch his snorkel's mouthpiece with his teeth. He makes three such lunges, each of them unsuccessful, before he gives up, takes a deep breath, and submerges his face--just in time to see Veronica's index finger pressing on the animal's back. The creature compresses instantly, but Anoop holds steady. Veronica places Cameron's hand on the frozen animal, and the other students, too, feel the hardness of cross-linked collagen. As Anoop watches their hands reaching in to investigate, his cheeks begin to swell with the pressure of unexhaled breath, and just when it appears they might burst open, admitting a gasp of seawater, Allie reaches across our circle and places Anoop's snorkel in his mouth. Through his glinting mask, he seems to look gratefully at her. Veronica begins to rub the animal's back, and at first, it appears to relax. But then something goes wrong. The creature skips liquefaction and moves straight to more drastic measures--the last line of defense. Because an echinoderm's nervous system speaks directly to those special cells embedded in the collagen matrix, telling them when to release their potent catalyst of change, the animal can freeze or liquefy whichever piece of tissue it needs to. This is how a brittlestar caught by the arm can throw off the entire limb, leaving it behind like the detached tail of a lizard: it simply liquefies the narrow segment of tissue that connects the arm to the central disk. And when a cucumber is under attack, it resorts to an even more radical tactic. It swiftly disassembles the collagen cables that hold its organs, violently contracts its entire body wall, and shoots its viscera out its anus. One can imagine that even the most menacing predator might be taken aback by such a move, and even if it weren't, it might at least be tricked into pursuing the evacuated innards instead of the now-hollow cucumber. Taking a bite of floating viscera, the predator would quickly learn that the animal is laced with a powerful toxin. The hollow cucumber, meanwhile, would have moved on, and would later regenerate, from stem cells in its empty body cavity, a complete set of internal organs. But if evisceration might distract a menacing predator, just think what it could do to Anoop. When the dark purple organs explode from the animal's posterior, he startles and flails, attempting to back away quickly. The guts purl and twist in his turbulence, forming a kinetic design of dark ribbons, diffusing colors, and loose round forms at the center of our circle. From the bottom of this turning mobile, the cucumber body sinks toward the seafloor. Rafe, evidently reluctant to let the animal escape, dives for it. He moves less smoothly than Veronica, but nonetheless manages to kick his way downward fairly rapidly until, about halfway to the bottom, he clutches the sides of his head and halts his dive. As he makes his way back toward the surface, holding his head all the way, Veronica and I look at each other through our masks. Had we suspected that Rafe didn't know what he was doing, we would have tried to catch him on his way down. But he plunged so suddenly, and it occurred to neither of us that he would neglect to equalize the pressure in his ears. The class has often included students who didn't know how to snorkel, but they have always learned the basics in just a day or two--and from the other students, not from us. Equalizing ear pressure is such a simple trick--as simple as holding one's nose and blowing out--and the early tutorials among newly acquainted students have always seemed to bring them together, so Veronica and I have never offered any formal introduction to snorkeling. Rafe, however, must have been watching Veronica, who somehow equalizes without holding her nose, and he must have decided that the graceless plugging of nostrils is unnecessary for talented skindivers. And now, as he rises to the surface holding his head in pain, Veronica and I can only hope that our habit of leaving it to the students to teach one another hasn't cost Rafe an eardrum. 2 The Vermilion Sea Field Station is solidly built. The foundation and the first few feet of wall are stone: a sturdy masonry of massive blocks. Atop the stone, the structure is framed with thick wooden beams, which are exposed around windows and doorways but elsewhere hidden beneath an earthy stucco. Wherever wood is visible, it is traced with the vermiform designs of a century of termites. The station was built in the 1880s by an American mining corporation, and I've often thought that the admirable sturdiness of construction must testify to a mixture of corporate optimism, which in the end proved misplaced, and colonial determination, which in the end proved futile. We're here to stay , the construction seems to say. We build for posterity . But around the time of the Mexican Revolution, the corporation disappeared. I've read conflicting accounts of the mine's closure. Some say the vein of silver at Las Flores, ten miles from the station, simply ran dry. Other accounts refer darkly to political circumstances . But what seems most likely is that the mining operation, like so many ventures before and after, was slowly but surely battered out of existence by the sheer difficulty of life and work in a relentlessly dry desert. Perhaps the one, anomalously flimsy element of the building--the roof, which must have been replaced many times since the mining company was here--suggests that even as they neared the end of construction, the Americans began to doubt their longevity in this place. Or maybe they just figured the roof would be unimportant, as it might never face rain. The masonry of the station's foundation extends to form a terrace between the building and the sea. Four rather sparse salt-cedars, or tamarisks, are evenly spaced across the terrace, and they provide a spotty shade. In more habitable parts of the world, such trees might be felled: they are scraggly; they shed long, dry, glaucous needles that infiltrate your hair, book pages, or lemonade; and when the sea exhales a thick humidity into the hot air, the tamarisks sweat an acrid turpentine that can take the paint off a car. In a sense, they should not even be here. Tamarisks are Eurasian trees that were introduced to the desert Southwest, where they are now blanketing riverbanks and displacing native species. But at two in the afternoon, when the unimpeded sun feels like a branding iron against your skin, and the interior of the field station heats to a stuffy ninety-five, you view the salt-cedars not with scorn, but with gratitude. They seem to be a necessary condition for human life. The five students who several hours ago watched a cucumber explode have pulled their plastic chairs together under one of the salt-cedars, and they sit in a half-circle facing the sea. In a separate island of shade, I am paging through my materials for the afternoon lecture, intermittently listening to them laugh and talk. Anoop is at the center of the half-circle, flanked by Cameron and Allie to his left, Chris and Rafe to his right. Rafe has wads of toilet paper stuffed in his ears, and their loose ends stick out like bleached pigtails. Fortunately, his headlong dive did no serious damage; Rafe's eardrums are intact. Nonetheless, for unspecified medical reasons, he has insisted that the toilet paper remain in place. The five of them are reviewing their moment of shock, and Anoop is making the others laugh wildly with his rangy reenactment of mad, backpedaling retreat from cucumber guts. I wonder whether Veronica could have foreseen this. Was it this very giddiness--with Anoop seated in the middle--that she had in mind as she poked the cucumber resting in Anoop's hands? Even if liquefaction had gone according to plan--if it had never led to swirling innards--the experience still would have given these five students something to relive here on the terrace. And Anoop, who otherwise might have had a difficult time finding his place in the group, would have been at the center of it all. As it happened, the moment was all the more shocking, and that much more effective in bringing them together. When the hilarity dies down, there is a lull in their conversation. Glancing up from my pages strewn with pine needles, I see the students staring out at the sapphire bay and the scorched umber islands that populate it. In the distance, on the other side of twenty-five miles of water, a mountain range of variegated pinks and pale grays extends as far north, and south, as one can see. It is not the coast of mainland Mexico, all the way across the Sea of Cortez, but rather a single long island known as Ángel de la Guarda. The channel between Guardian Angel and the east coast of the Baja Peninsula, where we sit, is known as El Canal de las Ballenas, the Channel of the Whales. It is four thousand feet deep. The wind is picking up, as it does most afternoons, and the bay's water, which was dark and glassy just a few hours ago, is now whipped up into whitecaps that march in ragged rows toward shore. This wind comes to us across the channel's cold water, making the temperature here in the shade almost comfortable. "Hey, Aaron," Cameron says in my direction, breaking their lull, "why doesn't something just mack that thing?" I look over as if I haven't been listening all along. I have no idea what cue might have told Cameron I was sitting here. Perhaps he heard me pull up a chair for lunch, and then never heard me leave. As I drag my chair now from my own salt-cedar's shade to theirs--to talk with them more easily in the rising wind--I am newly aware of the drumroll the plastic makes as it scrapes across the stone. I sit beside Allie, on the left edge of their half-circle facing the sea. "You mean why don't fish eat it?" I ask. "Yeah. I mean, it's slow and defenseless. Why don't they just mack it?" Cameron's eyes are not closed. They are crystalline blue-green, and offer only subtle suggestions that he cannot see: the gaze is immobile, fixed straight ahead; and at the outside edge of each eye socket, a slight indentation curves the bone. These gentle dips are barely noticeable, and they actually make his brow and cheekbones appear slightly more prominent and, it seems to me, handsome. He has short-cropped sandy blond hair, a muscular jaw and neck, and a body as burly as a marble Hercules. I have seen Cameron lifting weights in the campus gym, but I don't think his extraordinary brawn comes from pumping iron. I think it comes mostly from compensating for the absence of his left leg. A high-performance prosthetic, which looks like a sleek robotic limb, extends from Cameron's left thigh. He is remarkably dexterous with this device, but nevertheless, certain situations seem to require pure strength to compensate for the missing leg. On our journey down the peninsula, we spent the night in a landscape of colossal boulders. Watching Cameron pull himself up steep faces of granite, I understood why he looks so powerful. "The cucumber's toxic," I tell him. "It makes a poison called holothurin." "But don't people eat them?" Chris asks. "No way," Rafe interjects, and then he groans and clutches his stomach, as if the very thought of it might kill him. And in fact, I don't really know why the foodstuff called trepang or bêche-de-mer does not kill people, laced as cucumbers are with truly potent poison. I've read, for instance, that holothurins interrupt signals between nerves and muscles, and at sufficiently high doses, they explode blood cells. Several research groups have even tried to turn this chemical nastiness against aggressive tumors. When I tell the students about this work, Cameron says, "That's excellent. I didn't even know about that." It strikes me as a strange remark--why would he know about such work?--and I steal a glance at the other students, wondering if they, too, find it peculiar. Only Allie seems to have registered it. She's looking at Cameron with her brow furrowed and her lips parted, as if she had been on the verge of saying something when she caught herself and paused. In this oddly suspended moment, I realize that her face reminds me of silent movies, where pretty actresses had to be as expressive as mimes: her eyebrows are thin and arched, making her brown eyes look wide awake; her cheekbones are strong; and her mouth seems to move in an instant from bright glee to frowning gravity to--just now--a portrait of speech cut short. I'm still waiting for her to break her frozen pose and speak when Chris says, "Osprey!" and points down the coast. A sea eagle, flying a beam reach across the winds from the channel, sails toward us along the shoreline. "Oh, sweet," says Cameron, sitting up straight, as if he's preparing himself for something. "Those things are amazing." "It's heading right toward us," Allie tells him. "It's coming along the beach." Cameron turns to face it. The broad wings are virtually motionless--they make only slight adjustments in cant relative to the wind--and yet, in a second or two the eagle has traveled the length of the beach that stretches north of the station, and it is sailing over the rocky coast directly in front of us. Because the rocks ascend steeply from the water up to the station, and the stone terrace is several steps higher still, we and the osprey are at the same altitude, and as it passes, we look straight into a yellow, war-painted eye. It is fierce. The eagle vanishes to the south, and we are silent until Anoop, under his breath, says, "Osprey," and Cameron whispers, "That was amazing." Cameron, like the rest of us, is facing south--he is not still looking north, toward the beach--and this makes me wonder whether the broad wings sailing the crosswind might have been audible. If I had listened, would I have heard it, too? "Could I ask a question?" Allie asks, still a little quieter than we were before. "That's a funny question," Anoop answers, smiling to himself. For an instant, I expect Allie to go back to the question that arrested her, looking at Cameron, right before the osprey appeared. But instead she looks at me and says, "You know how Veronica said the cucumber's in the same family as sea stars?" "Same phylum," Chris says, correcting her. "Echinoderms." "Right--echinoderms. And she told us the things echinoderms share." "Like mutable tissue," Anoop says, again smiling to himself. Allie smiles with him, but also continues. "And a body divided into five parts, like a sea star's five legs." "Oh," Anoop says, "that's right. Where are the five parts?" "And how did it--how did evolution--take something with five parts, like a sea star, and turn it into one part, like a cucumber?" I hardly know where to begin, because this question could take our conversation in so many directions--the origin of basic body plans; the nature of deep evolutionary change; how we infer relationships between creatures as different-looking as sea stars and cucumbers. When so many scientific threads come together in a tight weave, it can be difficult to pick a single loose end and follow it. If we begin with the simplest inquiry, I figure, it will soon cross other threads, which we can pick and pursue if we choose. So we start with the most basic question: Where are the five parts? "They're actually still there," I say. "They just aren't so obvious." The group seems to lean inward, listening; these are clever and ambitious students, and they sense a puzzle to be solved, or even an opportunity to shine. "On the animal's underside," I continue, "the tube feet are arranged into three rows, from the animal's mouth to its rear end." "Oh," Cameron says, stopping me. "And there are two rows of bumps on its back." Exactly. Those tubercles, I tell the students, have got to be the remnants of tube feet. So with three functional rows along the animal's underside, the two vestigial rows along its back recall the five-part body plan of the ur-echinoderm--the same pentamerous symmetry that's so obvious in the five long arms of a sea star. In the cucumber, this basic body plan is obscured not only by the decay of two rows of tube feet, but also by elongation of the animal's body. The sea star is a flat animal, with its mouth on the underside and its five hydraulic pipelines running outward, along the five arms. The cucumber, on the other hand, is stretched out, with its mouth at one end and its anus at the other. The three rows of working tube feet are pushed close together under the animal's belly, and the tubercles on its back are somewhat scattered, making the cucumber look superficially like a long animal with symmetry that is basically bilateral --as in a fish, for instance, or a human. Pentamery would become obvious only if you were to cut the creature in half crosswise, revealing the five hydraulic pipelines running from one end to the other. Or if you were to examine the cucumber in the larval stage when it is known as a pentacula and looks more or less like an oval with five stubby tentacles. Anoop raises his hand, causing me to fall silent and look at him. At first, I'm puzzled, because his gesture is so entirely out of context. And when I realize what he's doing, I'm slightly annoyed. Anoop , I want to say, we are not in a classroom. We're sitting on a stone terrace, facing the sea, and this conversation was not scheduled on our syllabus . The others, too, seem to find the gesture peculiar, and for a moment we stare at him in silence. Perhaps because I say nothing, Allie finally calls on him. "Yes, Anoop?" The other students smile at this, but Anoop simply lowers his hand and asks his question: "Does that mean ontogeny recapitulates phylogeny?" Rafe guffaws--a laugh that sounds a little cruel, dismissive of Anoop for his classroom comportment. The meanness makes me forget my own annoyance--or perhaps transforms it to a twinge of guilt--and I'm tempted to remind Rafe that he has toilet paper hanging out of his ears. But Anoop and the others appear undistracted, focused on the conversation, and I should follow their lead. Anoop's question comes straight out of his studies of the history of biology. In fact, the very phrase ontogeny recapitulates phylogeny is lifted from one Ernst Haeckel, a nineteenth-century German naturalist and philosopher. Among biologists, Haeckel is probably known best for his lavish engravings of marine invertebrates. And he's probably known second best for being rather obscure, mystical, and wrong--or at least less right than another nineteenth-century German, named Karl von Baer. Given these deep and complicated roots in history, Anoop's question is perhaps not right up my alley, and before I venture an answer, I turn to look around the terrace for the person whose alley it rightfully is--my friend and fellow professor in this course, Graham Burnett. I met Graham in the first class of my freshman year at Princeton. It was HIS 291--The History of the Scientific Revolution. Graham wore a tie, sat in the front row, and often approached the professor after class to pose a question that I might or might not comprehend. I was trying to escape an identity as an athletic recruit, hoping to become a writer or a scientist, and Graham, who was unabashedly intellectual, seemed to hold the keys to the kingdom. For his part, Graham must have been grateful to find at least one fellow student who did not disparage his seriousness. So we quickly became friends, roommates, and companions in our mission--often pretentious, but always quite earnest--to make something of our minds. In fulfillment of a plan Graham laid out at the end of our freshman year, he is now the professor who teaches HIS 291 at Princeton. And although this precise realization of a blueprint for a life in academia might lead one to take Graham for something of a career company man, that would be a misreading. It is, admittedly, a misreading Graham readily allows, letting colleagues and students see him as the sweater-vested academic historian. But in fact, Graham has the most wide-ranging and diversely capable mind I've ever encountered. He once, for instance, led an expedition up the Orinoco River in Guyana. He wrote a courtroom thriller about a lurid murder case. And every summer he joins his friends to teach a course at the Vermilion Sea Field Station. Among our students, Graham is widely considered an eccentric genius--a classification he earns through wondrous eloquence, sartorial oddity, and mysterious scarcity. Instead of pulling up a plastic chair to chat beneath the salt-cedars, Graham often retreats to the staff house, a separate little cottage just uphill from the station. There, he lies on a cot in one corner of the covered porch and reads thick or obscure books. This year it's The Faerie Queene. And that must be where he is now, when I turn to look for him on the terrace and realize I'm on my own with a rather difficult audience: Anoop must know quite a bit about the historical debate over theories of recapitulation. On the other hand, Graham's absence will allow me to impersonate him intellectually, which is something I've improved at steadily over fifteen years of friendship. I would feel mildly depraved for pilfering someone else's intellectual identity--or, as he might put it, his modes of discourse --but the pilfering is entirely mutual. When Graham is talking about contemporary biology, he sounds suspiciously like his friend the biologist. In fact, we even have a name for our practice of disciplinary cross-dressing. We call it channeling--as in, "I had two biochemists in my seminar today, so I channeled you." My channeled historian of science is, of course, a ghost of the real thing. But with corporeal Graham supine beneath The Faerie Queene , a ghost will have to do. 3 To rephrase Anoop's question in words that are perhaps more accessible, if also less concise, we could ask: Does an individual organism, as it develops from embryo to adult, pass through a sequence of forms that reprise evolutionary history, beginning with the organism's most primitive ancestor and ending with its contemporary form? Or, to retain the brevity, if not the zip, of Haeckel's phrasing: Does an individual's development reiterate its evolutionary descent? If this all sounds too cosmically orderly to be anything but sheer mysticism, just consider the fact that early in development the human embryo exhibits unmistakable gill slits, while later on it has a tail as nicely formed as a monkey's. So the idea that an individual's development reprises its evolutionary descent was not without some basis in empirical observation. On the other hand, the theory also epitomized the predominant patterns of thought in the intellectual culture from which it emerged. The nineteenth-century German Idealists--thinkers like Goethe, Hegel, and Schelling--had a deep sense that the universe is unified and striving : a single set of natural laws governs everything (that's the unified part), and these laws conspire to cause a persistent push toward progress (that's the striving part). To understand such a universe, in which the same process is unfolding at every scale and in every entity, a natural mode of analysis is the detection of parallels between microcosm and macrocosm. For example, Hegel's works describe parallel trajectories of progress, discovered at vastly different scales: The Phenomenology of Spirit describes the rise of an individual from low brutality to enlightened perfection; the Philosophy of History recounts precisely the same ascending steps, but at the scale of world civilization. Haeckel's theory of recapitulation might be understood as a direct mapping of this same analytical structure onto the natural world: in Haeckel as in Hegel, a precise parallel is drawn between the individual's development and the much larger historical process in which the individual participates. For me, one of the most interesting discoveries in my conversations with Graham was that scientific theories are simultaneously a deduction from empirical observation and a reflection of predominant cultural views. Newton's view of God led him to expect inviolable and elegant laws of just the sort he found. Darwin's understanding of British economics assisted him enormously in his thinking about ecology and evolution. So while we may be tempted to scissor a theory into one part that is echt scientific and another that is a mere contingency of the time and place it was made, such an effort is confused and futile--no more feasible than it would be to divide, say, Monet's Water Lilies into one part that is French Impressionist and another that is a reliable picture of the world. To put the point differently: scientific theories are not mistaken insofar as they are the distinctive products of a certain culture's worldview, and they are not true insofar as they are separable from such a worldview. The ways Ernst Haeckel was wrong were no more distinctively German Idealistic than were the ways he was right. If we are to consider Haeckel's ideas seriously--without dismissing them as an Idealist's air castle--then one of the first questions we must ask is how the parallel he observed could come about. As both Darwin and Haeckel realized, there is a straightforward way evolution could engender its recapitulation in embryological development. First, say an organism has a developmental program that passes through an immature morphology we'll call A and ends in an adult morphology we'll call B. This organism, with developmental program A B, gives rise to two new species: Suppose each new evolutionary change occurs by adding a new segment of development to the end of the existing developmental process. So, for example, one species adds a new stage that ends with adult morphology C: The change from B to C is now the last step in development as well as evolution. Our recapitulation is brief, because we've imagined only one step of evolutionary change. But you can see that if evolution were to carry on adding new segments to the end of the developmental pathway, the recapitulation of ancestral adult morphologies could become extensive, stretching from ancient ancestors to contemporary species. But would evolution actually work this way? Would it really tend to add new segments at the end of the developmental program? Here's a metaphor that illustrates why it might. You have in hand a set of directions to drive from point A to point B in a large city--and it's an old city, like Rome, with many winding, one-way streets. As it happens, you actually need to get somewhere that's one block north and one block east of point B; call it point C. One way you might proceed is to drive to point B first, and then drive one block north and one block east. Alternatively, you could alter your route somewhere in the middle. But of course that's a risky proposition. Driving one block north and one block east before you get to point B might put you on a circuitous route in the wrong direction. You might find yourself merging inescapably onto an autostrada , or driving inadvertently into the Pantheon's pedestrian zone. You might never find your way to C at all. The development of an embryo, like the navigation of Rome, is a complex series of steps in which a small adjustment made early on could cause disruptions that grow as the process unfolds. In Rome, you end up lost; in development, the final morphology could be terribly dysfunctional. On the other hand, adding a short segment to the very end of a working set of directions--travel two short blocks from B to C; transform shape B into a slightly different one, C--could be far more likely to succeed. If it is, then evolution by natural selection probably does show a strong tendency for appending new segments at the end of development, rather than inserting them somewhere in the middle. And if that's the case, then development would indeed offer a quick reprisal of evolutionary history. 4 "Aye--but what's all this got to do with a sea cucumber?" It's Rafe. And as soon as he speaks, sounding rather impatient, I realize I've gotten carried away with my imitation of Graham and digressed too widely into German Idealism. This Attic setting--stone terrace overlooking the windblown sea; students gathered in a semicircle; filtered sunlight beneath our scrubby proxy for a plane tree--it has all lured me into philosophical mooning. But Rafe has not been similarly beguiled. In fact, he looks irritated. And the toilet paper in his ears suddenly reminds me of the steam that shoots from the head of a vexed cartoon character. In his application for this course, Rafe registered a definite confidence in the clear distinction between hard science on one side and every other sort of intellectual activity on the other. He was certain, for instance, that physics and chemistry would soon explain everything--including global climate and human consciousness--in terms of its physical constituents and their interactions. Interestingly, this view did not translate into diminished intellectual wonder. To the contrary, he expressed plenty of it, but only in a language of stern scientific reductionism. His application proclaimed awe, for instance, for what he called the incredible negative entropy of a giant squid. So whether he was talking about a salt solution or a sea monster--or even, actually, politics--Rafe seemed positive that there is one best way to talk about the world, and it is guided by modern science. Not by humanistic diversions to mystical Germans long since abandoned by the progress of research. But before I too can abandon the Germans and answer Rafe's question-- what's this got to do with a sea cucumber? --Chris says, "But I think I've always learned Haeckel was wrong." And Anoop adds, "Me too, but then I--" "I've never even heard of the guy," Rafe says, and his exasperation seems to demand what business a dusty German Idealist could possibly have in a science class. But for Chris and Anoop, Haeckel's relegation to the dustbin seems only to make it all the more intriguing that something actually sounds right in his ideas. And when I glance at Cameron and Allie, I find that Rafe is alone in his frustration: Cameron is smiling slightly, facing directly into the stiff onshore breeze; I have no idea why he's smiling--or even if he's listening--but he certainly doesn't appear impatient with our digressions. And Allie is looking kindly at Anoop, evidently waiting to hear where he was going when Rafe interrupted. Joining her, I turn to Anoop and wait to hear more. "Oh," Anoop says, endearingly surprised to have our attention. He inches forward in his plastic chair, brushes a few pine needles from his shiny black hair, and then explains that although he, too, had always learned that recapitulation was basically an outdated notion, he couldn't help wondering about it when I told them that larval I. fuscus has obvious fivefold symmetry. For it would seem--wouldn't it?--that the developing cucumber first displays the pentamery of the ancestral echinoderm, but then moves on to the more recently evolved bilateral symmetry of cucumbers. So doesn't it appear that, just in this case, ontogeny really does recapitulate phylogeny? The truth is, I've never really contemplated cucumbers in the context of recapitulation. But now that we're trying, the homely echinoderms seem to serve the theory beautifully. In fact, now that Anoop has outlined one step of recapitulation--the pentamerous immature, growing into the bilateral adult--I can't resist speculating about two more. After the sponges, the most ancient of animals are the Cnidaria--the jellyfish, anemones, and corals. Their symmetry is neither bilateral nor pentamerous, but radial: they have infinite axes of symmetry, like a circle. To see this, just imagine the lovely, translucent bell of a floating jellyfish. Cutting this form into equivalent parts would yield not five pieces, as in the sea star, nor two pieces, as in the cucumber, but rather a number of pieces that could range from one to infinity, and would depend only on how narrow you decided to make each wedge of the circle. Intriguingly, in a number of other phyla, including the cucumber's Echinodermata and our very own Chordata, the earliest stage of development is a radially symmetric ring of cells. Until about ten years ago, uncertainty in our understanding of the tree of life had obscured what is in fact a direct relationship between the radially symmetric Cnidaria and the early ancestor of echinoderms and chordates. Now that this direct connection in deep evolutionary time appears likely, we must wonder: Is the radial symmetry of our first developmental stage inherited directly from our earliest ancestor? Shortly after we are radial, we become, as you might expect, bilateral. What's more surprising, however, is that most echinoderms undergo the same transformation. When we imagine the bell of a jellyfish, our emblem of radial symmetry, alongside, let's say, a sand dollar, which is a nicely pentamerous echinoderm, the two shapes do not look so different; indeed, the one would seem to be just a block or two away, developmentally speaking, from the other. But many echinoderms don't take the direct developmental route. Instead, the nicely radial embryo grows into an early juvenile that is as legitimately bilateral as a tadpole. So the pentamery of adulthood might be only a few blocks away from the embryo's radial symmetry, but the developmental directions for walking around the corner lead first to the other side of the city. The young juvenile echinoderm--bilateral tadpole waiting to be a sea star, say, or a cucumber--floats around, eats a lot, and generally leads a life well adjusted to the open water. When it has finally eaten its fill, it experiences a complete rearrangement of its body. To get a sense of what it takes to transform a bilateral animal into a pentamerous one, just consider a sea star's rocky puberty: The juvenile's mouth, which is situated, like ours, near the top and on the front of its body, migrates down to the animal's middle, and then over onto the left side. Meanwhile, the limbs are absorbed, and the main bilateral body cavities branch out like growing saplings, becoming the hydraulic system of the adult. As transformations go, Ovid's metamorphoses are not more drastic. But how is this bilateral youth, which comes to such a dramatic close, an instance of recapitulation? We've mentioned that the phylum most closely related to echinoderms is in fact our own, the Chordata. As we know from personal experience, chordates are bilateral. What's more, the other phyla that are close mutual cousins of echinoderms and chordates are also bilateral. This tells us that if we were to inspect the common ancestor of echinoderms and chordates, we would find it to be a bilaterally symmetric animal. In short, before the ur-echinoderm discovered pentamery, its ancestor was bilateral. And before an individual echinoderm becomes pentamerous, it is a bilateral juvenile. Once again, we have a major transformation in individual development that seems to parallel a major transition in evolution. Following Anoop's lead, we've now put together a four-step series in symmetry, which we can trace through the development, as well as the evolution, of the sea cucumber. It goes: radial, bilateral, pentamerous, bilateral. As we come to the end of this four-step series, it is Chris who ventures to suggest, with some hesitation, "So we're saying Haeckel was actually kinda right?" Rafe is leaning forward, squinting. He looks from Chris, to me, to Anoop, and then back to Chris. "I thought you said he was wrong," Rafe says to Chris. "I said I'd always learned that, but how else do you explain this?" Rafe sits back abruptly and runs his palms back across his blond hair; then he starts reinstalling his tight ponytail, as if the act itself might help put things back in order. I glance at Anoop, and he seems to be looking at me out of the corner of his eye, though the lenses of his glasses are so small that his line of sight misses them entirely, and I must be very blurry to him. The slender fingers of one hand are covering his goateed chin and his mouth, as if he's about to speak but is not certain he should. He may be thinking there's another explanation, or at least the possibility of one, but he's holding his words--perhaps because he can't imagine why I haven't already spoken up about Karl von Baer. For the moment, however, Haeckel's main rival will have to wait, because Allie breaks our taut silence: "Cameron," she says softly, "what are you smiling about?" It's true. He's still wearing the same bemused expression, and he seems, I'm afraid, somewhat detached. He did follow the first few twists of our conversation--it was he who recalled the critical clue of vague rows of tube feet--but as we began to unroll Haeckel's theory of recapitulation, he peered into the wind and headed off in his own direction. Presently, he looks toward Allie as if she's just roused him from a daydream, and he says, a bit sheepishly, "I was just thinking about how all this got started." "What do you mean?" Allie asks. Her tone, sweet and encouraging, counters the note of diffidence in his voice. Cameron laughs a little and shakes his head. "Do you realize," he asks, "that this whole gnarly discussion started with that knobby thing that puked on Anoop?" Allie laughs, and Anoop says, "Anything to advance science." "Oh sure," Allie says. "Why don't you ask the cucumber about that." 5 I did not think much more about Cameron's bemused utterance until Veronica and I returned home, weeks later, and I began to review our days on the bay. Then, as I paged through my journal, reading entries here and there, Cameron's peculiar and seemingly trivial observation--that our entire conversation had begun with a sea cucumber--kept coming back to me. Naturally, I recalled his words when I found us testing out the rival theories--Haeckel versus von Baer--in other organisms: the needlefish; a stray dog; even our own species, Homo sapiens . But I also heard a sort of echo, a reminder to notice a conversation's point of origin, in other entries, too--like when a large desert cactus somehow led to the erotic fantasies of conquistadors; or when a vast skein of devil rays twisted itself into a glyph that seemed to demand interpretation; or when a frigatebird, hovering above us, induced Veronica to reveal how one of her heroes lost his life on the bay. In all those varied echoes and modulations of Cameron's initial observation, I began to sense the topography of an underlying idea, and I have come to believe that it needs to be explored. What lies behind this belief is in fact a suspicion, an awful hunch, that while the places we live and know have been scorched and destroyed, we have been blind to the destruction. And although we now live amid the smoldering wreckage, we hardly manage to notice that something has changed, because we hardly recall what these places once were. That may sound shrill or paranoid, but take it, just for a moment, as a hypothesis to be tested, a claim to be weighed against the evidence. We can begin with the evidence close at hand--a mud-brown loaf, rising to the surface on Veronica's palm--and work our way outward from there. In the summer of 1995, Veronica was a teaching assistant at the Vermilion Sea Field Station. On the first afternoon of her class, she watched the small local fishing boats, known as pangas, returning across the windswept bay. She stood from her chair on the terrace and walked down to the beach, where the fishermen would slide their boats ashore to unload their catch. The summer before, the waters had been rich with yellowtail, and Veronica was expecting to watch the fishermen heft from the open hulls of their boats the silver fish with scythe-shaped tails of dark yellow. What she saw instead surprised and puzzled her. The hull of each returning boat was filled from floor to rail with the dark brown ovoid forms of Isostichopus fuscus , massed like swarms of oversized larval insects. In retrospect, it is the timing of this story that seems most surprising. Three years earlier, in 1992, fishermen on the Pacific coast of Ecuador had finally depleted what had been an exceedingly productive I. fuscus fishery. With their local livelihood vanishing, the fishermen moved their efforts farther offshore, to the Galápagos Islands. But the Galápagos, as a prominent tourist destination, was under closer scrutiny than other areas of Ecuador, and when the cucumber population began to crash there, too, the government responded publicly and dramatically. In 1994, Ecuadorian regulators imposed a moratorium on the harvesting of cucumbers. The government of Mexico must have been watching, because regulators there immediately declared their own ban, and they did so, as best I can tell, without any real indication that Mexican populations of I. fuscus were also in jeopardy. The following summer--the first season I. fuscus was absolutely off-limits--was when Veronica watched panga after panga full of cucumbers arrive at the beach. So why was a ban met with a binge of extraction? The answer might be that the new laws in Ecuador and Mexico caused a spike in the price of cucumber on Asian markets, luring more fishermen than ever into the business. And although extraction of a cucumber was just as illegal in Bahía de los Ángeles as it was in the Galápagos, Mexican enforcement was weaker, resulting in a shift of fishing pressure from one place to the other. I could be wrong about the steps in this chain reaction, but in any case, the summer of 1995 wrought a noticeable change on the reefs of the bay. Veronica has told me that before that summer, many reefs supported about one brown cucumber every square meter. In every summer since, they've been so rare that the discovery of one has been cause enough to gather the students. The claim we set out to test (beginning, humbly enough, with a brown cucumber) was that the places we live and know have been despoiled, and we've hardly taken notice. It's clear that the cucumbers are gone, but is it true that their absence is overlooked? When Veronica first showed me a sea cucumber, she had never told me about the catastrophic summer of 1995. Without that historical memory, I took the discovery of an exotic organism, a creature I had never before encountered, as an indication of the reef's ecological health; certainly it did not occur to me that the number of cucumbers was in fact a sign of devastation. And I have heard many students misjudge the reef's condition in much the same way. Upon emerging from her first dive in the Vermilion Sea, Allie said breathlessly, "I can't believe how much stuff there is!" Why would it occur to her that ten years ago there was so much more? Of course, the students and I are but visitors to Bahía de los Ángeles, and one might suggest that it is merely our recent arrival that makes us so ignorant of what was here before. But there is an entire generation of Bahíans, now teenagers, who also did not see the bay before 1995. They, like us, have no recollection of a reef replete with cucumbers. We once hired the teenage son of a local fisherman to help us with the class. He often sat in the panga and listened to music while the rest of us explored the reef, but we occasionally brought creatures over to the boat to discuss with him. When we brought over a cucumber and asked him if there used to be more, he said, "No, there used to be less." In a way, he was right. The past few years had brought a slight expansion of the cucumber population, perhaps on account of a sudden spasm of severe enforcement by the Mexican government. But the state of the population that he took as his starting point--what he considered the natural condition--was in fact a state of catastrophic depletion. So the cucumbers are gone, and their absence from the reef is unremarked--not only by those of us who are late-arriving visitors, but also by younger generations of locals who, like us, first encountered the reef without its former inhabitants. Admittedly, I. fuscus is a modest example. It is, after all, an ugly and inconspicuous animal, and perhaps that is why its decline is so easily overlooked. But what of the Vermilion Sea's more charismatic creatures? Surely their disappearance would leave more noticeable lacunae. I might have thought so, until I encountered the writings of Joseph Wood Krutch. Krutch was a professor of drama, which is perhaps not the sort of professional bio one expects for a man who traveled Baja in the 1950s, a time when the only other American visitors were a few intrepid botanists. But he had taken an interest in the desert around his home, in Tucson, and he had heard that the most extreme of all deserts--drier, more isolated, more punishing than any other--could be found about three hundred miles down the Baja Peninsula. So he went, and, being a man of letters, he wrote about it. On his second visit to Bahía de los Ángeles, a small plane deposited him at an airstrip that used to run just behind the beach: Ten minutes later the airplane was taxiing across the strip again and I, standing alone on the beach, waved it away. Yes, the scene was as intriguing and as beautiful as I remembered it. A few hundred yards from shore the turtle boat rode at anchor on the blue water. The great beach was empty except for two ten-year-olds plodding across it and carrying between them a fish (Yellowtail) as tall as they. In some ways, the scene today is the same. The water is still very blue. And the beach remains broad and beautiful, despite the row of spartan cinder-block cabanas that the Diaz family has built behind a knee-high seawall. But the details--the biological details--are different. Yellowtail are still sometimes caught by the sport fishermen who spend their weekends in the Diaz cells, but I have never seen a yellowtail as tall as a ten-year-old. In fact, I have never seen one as tall as a four-year-old. And, more striking, what is now a sportsman's prize catch was formerly an overabundant staple: Go out a few hundred yards , Krutch wrote, and in an hour you will take a dozen yellowtails averaging eighteen or twenty pounds each. But it is another detail that, for me, provides the more poignant contrast with today's bay. Krutch mentions a turtle boat. A turtle boat. When I first read this, it sounded almost fantastical, because I had never encountered a turtle in the Vermilion Sea. To this day, I have seen only eight--and three were ones that we ourselves released at the beach, assisting Antonio Reséndiz, a local man whose mission in life is to bring back the turtles. But according to Krutch, on a typical evening in Bahía, a twenty-five-foot turtle boat may come in loaded with fifteen or twenty huge turtles, which will be added to the others, collapsed in sad resignation in a covered pen near the water. When Veronica first brought me to Bahía de los Ángeles, fifty years after Joseph Wood Krutch had arrived by plane, I found a place that was unimaginably alive. At sunrise of my first day, I watched from the terrace as whale spouts erupted and hovered in the morning haze; before one had evaporated, the next would appear elsewhere in the bay. When the sun had become so strong that the spouts would burn off before they could take shape, I put on my mask and snorkel and swam out over the rocky reef. Twenty feet from the research station, I found beautiful, alien creatures: Christmas tree worms and brittlestars, crystalline shrimp and velvety green anemones. Later, as we ate lunch on the terrace, a dark shadow slid across the station reef, and I looked skyward, thinking it odd that a single cloud could survive such heat. But there were no clouds, and Veronica laughed at me, because the cloud shadow was in fact a whale shark gliding through shallow water. Over the next few days, Veronica told me about the creatures she had seen when she herself had first arrived, but which, for one reason or another, didn't seem to be around anymore: the cucumbers; the elegant terns; the sharks. When Lane McDonald, Veronica's college mentor, arrived at the research station, I asked him what had vanished before Veronica's time. He mentioned the sun stars, Heliaster kubiniji , and he said he thought there had once been more bottlenose dolphin, too. Then, reading Krutch, I learned about the turtles, and from Antonio I heard that it wasn't just one sort of turtle, but four. And suddenly the bay, which at first had seemed only full of life--straightforwardly, unreservedly full of life--was now growing crowded with the ghosts of its former inhabitants. And the further the stories reached into the past, the longer became the list of the missing until, eventually, the ghosts seemed to outnumber the living. It is disturbing to learn from a witness of history that a beautiful place, which one took to be pristine, is in fact despoiled. But it is more disturbing to realize that the witness himself confronted the very same lesson long ago. Just as I have come to see that the bay is now but a remnant of the one Krutch encountered, Krutch himself realized, with great dismay, that the bay he knew was but a remnant of its past. And, charting another turn in the spiral, Krutch recorded his realization by citing his own witness of the past, who had learned the same lesson a hundred years before. Krutch quoted Henry David Thoreau: I take infinite pains to know all the phenomena of the spring, for instance, thinking that I have here the entire poem, and then, to my chagrin, I hear that it is but an imperfect copy that I possess and have read, that my ancestors had torn out many of the first leaves and grandest passages, and mutilated it in many places. I should not like to think that some demigod had come before me and picked out some of the best stars. I wish to know an entire heaven and an entire earth. Over the past ten years on the bay, I have tried to gather up scraps torn from the poem. I've collected them from Veronica; from her mentor Lane; from the turtle man Antonio; from the wandering drama critic Krutch; and from many others. With my hands full of ragged bits and scraps, I might be inclined to believe that the bay has been more severely rifled--more drastically abridged--than other places I've lived or visited. But the opposite is true. In the bay, many passages were lost so recently that people I knew could recite them, and the poem, pared and slashed though it was, remained sufficiently coherent to betray certain gaps. In other places I've been, so much was lost, and lost so long ago, that there are hardly reminders of the poem's former content. Who on the Eastern Seaboard is struck by the absence of migrating gray whales, or nesting sea turtles, or playful and clever sea mink, or river-frothing runs of salmon and eel? Yet they were all there, and there in great abundance. We live amid the wreckage, yet we hardly notice that something has changed. 6 Why are we blind to the destruction--so forgetful of what was here? What have we lost, and what can be done? These are the questions, broad and unapproachable, that seem to lie just beyond Cameron's modest observation, like a vast landscape accessed through a keyhole. It seems to me that our blindness to destruction is partly a problem of memory, and partly a problem of perception. We've already touched on the problem of memory: knowing only the natural world we've encountered in the short interval of a life, we fail to notice the substantial transformations wrought by previous generations; and so we overlook the absence of all that was already gone when we ourselves first arrived on the scene. The problem of perception, for its part, is like one of those Greek gods who take the form of a different animal for each of their misdeeds. It will show itself, in several different guises, in the chapters to come, but for now its general shape can be vaguely conjured with a comment once made by a friend. She is a Kantian philosopher, as well as a devoted denizen of cities, and she once described for me her experience of entering the woods. Her first thought, she said, is generally something like, There's nothing here. I want to go home. What happens, it seems, is that she faces an unfamiliar and overwhelmingly complicated world, and she doesn't know what to look for or where to focus her attention. As a result, the profusion of detailed complexity blends into a surface of monotony, which presents itself to her as nothing . A mud-brown lump on the rocky bottom is easily overlooked. But I. fuscus , resting on Veronica's palm, in the light nearer the surface, became the starting point for innumerable strands of narrative and investigation. There were straight scientific questions, about collagen or evolution or holothurin; there were histories, threading back to nineteenth-century Idealists; and there were Veronica's memories of former fishing seasons--recollections that merged in turn with the paths of causation linking Ecuador and Bahía. This unfurling of I. fuscus suggests that the interest of an organism--broadly speaking, its meaning and value--can become clear only when it is seen and approached as the origin of our stories. When we follow the threads of these stories outward, tracing them to other organisms, or cultures, or individuals, we begin inevitably to reconstruct a kind of dense historical ecology, a thick description of a creature's place within webs that are not only biological, but also conceptual and social. And it is in this dense weave that we have our best chance, I believe, of understanding what has been lost and what can be done. In Claude Lévi-Strauss's words, animals are good to think with. In Cameron's, the whole gnarly conversation starts with a sea cucumber. Copyright © 2013 by Aaron Hirsh Maps and illustrations copyright © 2013 by Emiko Paul Excerpted from Telling Our Way to the Sea: A Voyage of Discovery in the Sea of Cortez by Aaron Hirsh All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.