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Survivors at the twilight of the planet.




  The Time Traveler (for so it will be convenient to speak of him) was expounding a recondite matter to us. His gray eyes shone and twinkled, and his usually pale face was flushed and animated. The fire burnt brightly, and the soft radiance of the incandescent lights in the lilies of silver caught the bubbles that flashed and passed in our glasses.
H. G. WELLS, The Time Machine

There is but one place that I know of where time is suspended. High above the Coral Sea in a 747 bound for Australia, I sit with nose squashed against the frigid window, a bright moon and Southern Hemisphere stars starkly visible. All around me fellow passengers try to sleep, crammed into this silver cigar suspended above the Earth, chasing the night as we head west, the endless night. What time is it; what is time? A Quantas cabin attendant passes among the quiet throng, and unbidden, tells the passenger in front of me that there is no time up here, just distance. I shrug at this in affirmation; how can she be wrong, veteran of a thousand trans-Pacific voyages? Its 4 A.M. according to my watch, West Coast North American time, but 9 P.M. here according to my calculations, twelve hours into the flight. Three more hours to go to arrive in Australia, then three more hours on a cold airport bench, then two more in another plane to


arrive in New Caledonia, my eventual destination. Is it past, present, or future here? Once again, H. G. Wells seems palpably present. On such a fight there seems no possible ending; all that came before is but memory, all to come is speculation. Reality is the cramped seat, the tiny window, the suspension above a dark Earth assumed to be below, and the baleful moon in its sprinkling of stars. I will never be closer to these stars, I muse. A book, quiet reflection, attempts at fitful sleep. The opposite of time.
And then, somehow, against all expectation, the flight does end, and time resumes, this voyage becomes memory, ending in a place where time, at least as counted by evolution, is suspended as well.
I had first come to New Caledonia in 1975, crossing the widest ocean for the first time, finally leaving the long den of school life. I had come to study an icon of evolution arrested, the chambered nautilus, the antithesis to this book not the future of evolution, but an evolution ended. Then I was amphibious, for I had taken to the sea early in life. Donning scuba gear at 16, I became a salvage diver at 18 and an underwater instructor at 19. Being young (and thus immortal), I had no fear of the sea, for I felt more at home under its surface than I did living among the creatures of air. Thus, for three months in my twenty-fifth year of existence, I lived a life of the sea, of study, on an island that had once been part of Gondwanaland, splitting off during the Age of Dinosaurs to be carried by continental drift to its present tropical resting place, east of the Great Barrier Reef in Australia. New Caledonia became its own laboratory of evolution, eschewing mammals, instead evolving a unique fauna of birds and insects and flora derived from ancient Gondwanaland, a flora dating back to the time of the mammal-like reptiles of 250 million years ago. Cut off from the rest of the world, New Caledonia became a museum of the ancient, with fully half of its plants found nowhere else on Earth, and many of great antiquity. Evolution seems to have taken a long vacation here. In the first month of the new millennium, in my fiftieth year of existence, I returned to this ancient place, place of ancients.
Tropical, exuberant, gigantic as islands go, with high mountains and dark rock ripped from deep within the Earths mantle and thrust upward in the cataclysmic breakup of Gondwanaland, New Caledonia looks like no other place on Earth. It is covered with forests of Norfolk pine and other relics of the Mesozoic Era, and only where humans have imported their plants and animals does it seem like the rest of the world. Coral reefs stretch out far from land, and one of the worlds wonders, a Great Barrier Reef as impressive as that of nearby Australia, surrounds the three-


hundred-mile-long island. It was outside of that reef that I had made the seminal discoveries that launched my scientific career. It was also in this same place that in my thirty-fifth year one of my closest friends would die in my arms following a dive together along this reef, our blood mingling as I vainly tried to breathe life back into his ruptured young body. Following that horrific extinction I had no desire to see this fatal shore again, but time eventually did its healing. It was to this same place that I finally returned, to the same stretch of reef where he had died, the blue sea finally purged of his red blood so long staining my memories of this place.
Twenty-five years seemed to have flashed by in an instant, and at the same time had crawled by so slowly. Old friends I had not seen for a decade and a half or more, friends who greeted me so warmly and with such emotion that I wondered who that man was that they had known, to be remembered so fondly, a man I no longer was? A huge block of time as measured by the life of a man, yet invisibly short as reckoned by the Earths timekeeper, and by the clock of evolution. Yet as I walked the old beaches and places I had known so long ago, I found more changed on this island than not; I found that a quarter century of human development had radically transformed a place I remembered as still pristine. It was not just the new buildings, roads, factories, the vastly increased human population so evident everywhere, but the look of the place, the air less clear, the garbage now clogging beaches so pristine in my memory. I found myself yearning for the clear warm water of the reef, so far from shore, to see once again the ancient nautilus rising up from its deep daytime keep to stealthily prowl the shallows at night under the cover of darkness.
In this I was not disappointed.
Within a day of our arrival we were at sea, in a French oceanographic vessel chartered by the television crew that was behind the entire adventure. We anchored outside the barrier reef, 12 miles from shore, and started the chores necessary to find Nautilus.
The television company needed to get film of this ancient living fossil, and left nothing to chance. We set deepwater crab traps late one afternoon, a sure way to catch Nautilus, then spent the night waiting. At first light in the morning we winched the heavy traps up from their resting site 1,200 feet below. Seven nautilus and several temperamental deepwater eels and crabs were found in the traps, and we were ready to use these as stand-ins if, after all, we were unable to see wild animals in the night. With animals in the bank, there was nothing to do but wait for nightfall. Our boat was anchored right at the edge of the reefs drop-off, and I could


see the change of color from light to dark blue as our boat drifted back and forth over the drop-off. I spent the day snorkeling in this ancient ecosystem a habitat now so threatened in many parts of the globe.
The livid tropical sun ran its course, and the deep, rich colors of the reef created by the suns equatorial light faded as the afternoon waned. Once again I felt the disorientation of a twilight running its course too quickly, the transition from day to night so rapidly accomplished in this region of the globe. In the deepening gloaming I donned old familiar gear, the museum pieces of equipment I had dived in so long ago in this place, well maintained and still as efficient as it had been a quarter century earlier. But it was not just my diving gear that seemed out of place. I was an anachronism among the younger divers with us on this expedition, young men and women sporting the colorful panache of the newest generation of diving equipment.
The warm, dark night of the tropics finally extinguished all light, and it was time to dive. We splashed in a bit after 8 P.M., immediately turning on bright underwater lights, and began searching for Nautilus, by now presumably newly ascended from its much deeper daytime haunts. I was diving with an old friend and fellow old man, Pierre Laboute, with whom I had seen my first wild nautilus almost exactly twenty-five years before. We brought with us two of the nautilus that we had caught earlier to be sure that the television company financing this elaborate and expensive expedition would get the footage they needed. But they proved unnecessary, and I surreptitiously released them back into their dark home, for near the end of the dive we saw not a trapped nautilus, but one that had come up to us from its retreat a thousand feet below to prowl these shuttered reef shallows in this dark tropical night. And so again two divers met in the dark, one a new species, the other one of the hoariest survivors of our planets long history.
Once speared by our lights, the nautilus swam in long arcs, and we followed it for some time, two humans and a living fossil engaged in a slow-motion chase across the coral reef landscape in the dead of night. The white shell and magenta stripes of this nautilus seared brilliantly while transfixed by our powerful diving lights, and I have no doubt that the animal inside was terrified, if that word can be used for a creature with a very small brain. All afternoon the wind had been rising, and with it the sea, causing us to be buffeted even at the forty-foot depths we now swam through, but the nautilus simply motored through this swell, and we in our turn as well. Too quickly my air ran low, and my moments as a fish were over. When last seen, the nautilus was swimming in a seaward direction, back toward the


security of the depths, and with this last vision Pierre Laboute and I headed back toward our boat in a sea now convulsing in the rising wind.
But my memory of that dive now turns not on this nautilus, but on time. Here we were encountering an animal not much different from the nautiloid cephalopods of 500 million years ago, a time when animals any animals were new things on this planet. In the nautilus it is not time, but evolution, that is suspended. And so, in that dark sea, I swam with joy at seeing this old friend, but with confusion at the unexpected strength of the feelings that this encounter was producing in me, and with the realization of how time had affected me as well: I could not dive as well, I was not as comfortable in the water, I had aged. There was a very good chance that a further twenty-five years would find me dead or, at seventy-five, certainly not diving the outer reaches of the New Caledonia barrier reef. Time, and time travelers.
I left the rich nighttime reef with its cargoes of animals and climbed up out of Mother Ocean, the clumsy tanks still slung on my back, into the face of a video camera, my face white and rubbery, nose running, a picture of a mechanically amphibious man caught in the web of time. I slung my mask and fins onto the pitching deck and smiled at my companions, sad for those who had to stay on the boat during our long dive, those that had missed a great privilege. They asked what we had seen, and I could only answer, wonders.
Coral reefs, with their diverse inhabitants, rich plankton, huge fish in great schools; indeed, these are wonders still here in this warm New Caledonian ocean. On the nearby land great flights of fruit bats swarm among the endemic tree species in the lush rainforests and dry forests, legacies of bygone geologic ages. Along the shores, spreading mangrove swamps guard a treasure trove of species.
Wonders, indeed.
Will those wonders continue?
All that has gone before in this book has given us a peek into the future, but that peek has been timid and so far limited to the near future as measured in thousands, or at most a paltry few millions, of years. But here, at the end, let us try a longer view. If the nautilus and its ilk can last 500 million years, persisting through trials of asteroid bombardment, tectonic cataclysm, rapid (and slow) climate change, reversal of the Earths magnetic fields, nearby supernova explosions, gamma ray bursts, fluctuations in the intensity of the Earths magnetic field, and surely much more still unknown to us, why not us? Why cant our species weather 500 million


more years? Or a billion years, for that matter? Surely we can nudge aside the really large comets that head our way every million years or so.
To conclude this book, let us go forward in time until we reach that far-off land first seen by H. G. Wells. Let us go 500 million years into the future, the length of time that the nautilus has already existed, to a time closer to the end of the Earth than its beginning, and speculate about how the end of evolution and of animal life on this planet may come about.

By 500 million years from now the Earth, as a planet of life, will have aged considerably. Today, in this dawn of the Age of Humanity, we are already on a planet whose habitability has gone from middle to old age, a planet nearer the end of its life than the beginning. In those far future days, the engine of evolution will begin creating a rearguard action against the eventuality of our planets death, a slow backing toward the final accounting that old age, even the Earths, brings. By a billion years from now the Earth will no longer be habitable. Somewhere, then, between those two times will be a time when life on this Earth will have to adapt to ever-increasing heat and decreasing carbon dioxide. It is then, in that far future, that the types of animals and plants might finally prove to be exotic compared with our present-day biota.
The big problem, of course, will be the sun. Like all stars, it contains a finite amount of fuel, and as the tank empties, the temperature will increase. The amount of hydrogen being converted to helium will decrease, and heavier material will begin to accumulate. The sun will expand in size, and the Earth, the once equable Earth, will face the prospect of becoming the next Venus in our solar system: a desert without water, a place a searing heat, a burned cinder. That will be our fate. What will precede it?
Between 500 and 1,000 million years from now there will still be clinging survivors of the Cambrian Explosion of 500 million years ago, the last twigs of the once vigorous tree of life. Let us imagine a stroll along the seashore in such a world. The sun is gigantic, the heat searing. The equatorial regions are already too hot for all but microbial life, and it is only in the cooler polar latitudes that we can see the ends of animal life on Earth. Plant life is still present, but the amount of carbon dioxide in the atmosphere has shrunk to but a trace of its level during the first evolution of humanity. Only those plants evolved for life in this low-carbon-dioxide environment can be seen: low shrubbery with thick, waxy cuticles to withstand the searing heat and desiccation. There are no trees. Gone are the forests, grasslands,


mangrove swamps, and meadows. The oceans are in the process of evaporating away, and huge salt flats now stretch for untold miles along their shores. There is no longer animal life in the sea, save for crustaceans adapted to the very high salt content. The fish are gone, as are most mollusks and other animals without efficient kidney systems, such as echinoderms, brachiopods, cnidarians, tunicates all the groups that were never good at dealing with changes in the saltiness of the sea, or at moving into fresh water. There is still land life, for animals can be seen along the shores, but they are low, squat, heavily armored creatures, and their armor is not for protection from predation, but for protection from the ever-present heat, salt, and drying.
Inland from the sea there is a different vision. Lichen, a few squat low plants. Other desultory animals, some of them arthropods, a few of them vertebrates. All the rest of the world is a desert, a place of heat and dying.
The birds are gone. So too are the amphibians. Whole classes, even phyla, are now disappearing from the Earth like players from a stage when the play is ending.
There are still lizards, and snakes, and scorpions and cockroaches.
And humans.
All of humanity, or what is left of it, now lives underground in the cooler recesses of the Earth. It is as if at least part of H. G. Wellss vision has come true. In a sense, humans have become his Morlocks, a troglodyte species. There is too much radiation from the growing sun for humans to last long on the surface of the planet. Humanity, by necessity, has had to go underground, becoming the new ants of the planet. But physically, humans have not changed much. They know the end is near. There is no way off, no path to other, younger worlds. Space turned out to be too vast, the other planets in the solar system too inimical, the stars too far. Their Planet Earth is old and dying. They do not mourn the many animals the Earth once had. It is hard to remember things that happened 500 million years ago.
Once there was a future to evolution.






Biological Futures
Niles Eldredge
PREFACE   xiii
INTRODUCTION The Chronic Argonauts 1

The Deep Past: A Tale of Two Extinctions

TWO The Near Past: The Beginning of the End of the Age of Megamammals 37
THREE Into the Present 47

Reuniting Gondwanaland


The Near Future: A New World


The First Ten Million Years: The Recovery Fauna


After the Recovery: A New Age?


The Future Evolution of Humans


Scenarios of Human Extinction: Will There Be an After Man?


Deep Time, Far Future



INDEX   183

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