The Next Species: The Future of Evolution in the Aftermath of Man (2 page)

The rains grew heavier and we put on waterproof army ponchos over Gore-Tex parkas. But this didn’t stop Rodríguez from climbing out on a wet, slippery tree limb when she thought she heard a new frog croak. She found nothing out on the tree limb that night, but she came across twelve new species in the course of our four-week visit.

The wonder of evolution is exemplified in these rarefied, verdant corners, where life adapts to tiny ecological niches of nature that require elaborate maneuvers for others to take advantage of. The question is: Will nature provide the necessary niches and maneuvers to meet the future? Will the tropics be part of the rescue, if there is one? And will modern man be along for the ride?

The palpable haste of modern biologists is due partly to the fear that we may be at the start of a mass extinction event—a loss of over 75 percent of plant and animal species. Such events have occurred only five times in the past 600 million years, when animals first appeared in the fossil record. And now scientists suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. A recent report in the science journal
Nature
from biologists at the University of California, Berkeley, states that we could reach the extreme of a mass extinction in as little as three centuries from now if current threats to species are not alleviated.

It took
Homo sapiens
less than 200,000 years to reach a burgeoning population of one billion in 1800, but by 2000 we topped off at six billion, and by 2045 we are projected to reach nine billion. It is an unprecedented surge of growth, with unimaginable risks and innumerable side effects—the wellspring of a raging crisis.

And yet it is a dilemma man appears to ignore, though it is becoming more difficult to disregard as the list of earth’s endangered plants and animals keeps growing due to our multiple assaults on the environment. We have become a deadly virus to nature.

Our massive overpopulation and accompanying decimation of earth’s natural resources, if pursued unabated, may lead to man’s own demise. Yet, as great as our footprint has been, from a geological perspective, we’ve done all this damage in a brief moment. If one looks at the entire
history of earth as a twenty-four-hour day, we only entered the picture around the last seconds of that day. We work fast.

Of course, earth will recover, no matter how devastating our brief visit here. After all, just because it may mean the end of man, it won’t be the demise of all biological life. Life is resilient. Plants, animals, and microbes will survive, adapt, diversify, and proliferate. New plants will evolve to vanquish our monocultures of corn, wheat, and rice. With far fewer animals around, those species that survive the bottleneck of extinction will move into newly abandoned spaces. With little competition, they will thrive and rapidly evolve.

It’s all happened before.

Recoveries followed all the mass extinctions, no matter their causes. The Ordovician extinction event 443 million years ago destroyed 86 percent of species with a barrage of alternating glacial cycles. The Devonian event 359 million years ago took out 75 percent of species with a one-two punch of global cooling and global warming. The Permian event 252 million years ago destroyed 96 percent of species with a Siberian supervolcano. The Triassic event 200 million years ago took out 80 percent of species with a combination of global warming and ocean acidification. The Cretaceous event 65 million years ago destroyed 76 percent of species with the impact of an asteroid. Though we have identified the prime suspects here, each of these mass extinctions had multiple causes.

The best known, the Cretaceous extinction 65 million years ago, was the primary result of an asteroid impact, though it had help from a supervolcano, the Deccan Traps in India—traps being large regions of volcanic rock with step-like plateaus and mountains that are typical of flood basalt eruptions. The Permian extinction 252 million years ago, the child of a volcano, also had help from the collapse of ocean currents, among other causes. Yet, despite their enormous destruction, the Permian
extinction opened the door for the dinosaurs, and the Cretaceous extinction opened the door for mammals and man.

Extinction is a powerful creative force, says Douglas H. Erwin, a paleobiologist at the Smithsonian Institution. In his book
Extinction: How Life on Earth Nearly Ended 250 Million Years Ago
he writes,
“From the wreckage of mass extinctions the survivors are free for bursts of evolutionary creativity, changing the dominant members of the ecological communities, and enabling life to move off in new and unexpected directions.”

Anthony Barnosky, a professor of integrative biology at the University of California, Berkeley, and principal author of the
Nature
paper, says that the critical component in determining if we are headed toward a mass extinction event is the status of critically endangered, endangered, and vulnerable species.
“With them, Earth’s biodiversity remains in pretty good shape compared to the long-term biodiversity baseline. But if most of them die, even if their disappearance is stretched out over the next 1,000 years, the sixth mass extinction will have arrived,” he says.

He thinks that if we save the species now considered in trouble, we may have a chance. But our work at saving endangered species has resulted in many cases of what paleontologists refer to as “dead clade walking”—“clade” meaning groups of organisms. An example of lingering species is the California condor, which is threatened by lead poisoning, lethal pesticides, and expanding urban areas. It has cost millions of dollars and countless hours of work to preserve critical habitat, raise captive birds, and release them to the wild—but will the California condor be here for the next thousand years?

And if so, will other birds survive the bottleneck of mass extinction? Will reptiles, fish, insects, mammals, and perhaps even man survive? And how will they differ from the current versions of their species? That is what we will investigate here.

This book looks at past extinction events, the evolution of man and nature, evolutionary changes already under way, and the evolutionary changes likely to occur. Our title,
The Next Species
, is used in its plural
sense. We are interested in the next species of marine and terrestrial animals as much as we are in the next species of man. The research was built on scientific papers, books, as well as personal visits and interviews with experts. Its vision is based on fossil evidence from the past, studies of the present, and expert predictions of the future.

I visited more than seventy scientists from Harvard, MIT, Duke, the Smithsonian Institution, the American Museum of Natural History, UC Berkeley, Stanford, the University of Indiana, the University of London, Oxford University, the Max Planck Institutes, and more. We spoke on the phone with many others.

Many, like Hans-Dieter Sues, curator of vertebrate paleontology at the Smithsonian, think that extinction is a normal process of life.
“Virtually 99.999 percent of all life on the planet has gone extinct,” says Sues. “And so will
Homo sapiens
. Maybe in one thousand years we will have figured out how to do interstellar travel, so if things go haywire down here, we can take off and go somewhere else. But it’s just as possible we will mess around with our own genome and create some sort of race of superhumans, and they’ll drive us to extinction.”

This book looks around the world for lessons in evolution. What can past mass extinctions teach us? Can pristine ecosystems exist in war zones and nuclear accidents? What can 30,000-year-old fossils under Los Angeles tell us about the diversity of life? Will scientists rewild the Americas and Europe with elephants, cheetahs, and lions? Will jellyfish and giant squid dominate the oceans? Does disease fester in a world devoid of its native species? And what about the chances of an escape to Mars?

We’ll also explore the possibility of other forms of life evolving. Could isolation in the wake of a mass extinction provide the evolutionary opportunity for another species of man? Will genetics provide our children with better minds, longer lives, and unique bodies? Or will scientists figure out how to upload the human mind, making our bodies obsolete, so that we live on as robots or avatars in a virtual world.

The possibilities abound.

I
F YOU’RE CURIOUS
as to what a mass extinction looks like, you might want to visit the remains of the Capitan Reef at Guadalupe Mountains National Park, the highest mountains in Texas. Life abounded in the seas back then, but the dinosaurs had yet to appear. The creatures that walked the dry land were not as enormous, nor as diversified, as they would become later. The continents were bound together in a single landmass, but as it broke up and drifted apart, the movement provided the isolation necessary for new species to evolve. Still, life had to sidestep the Permian extinction before it could truly flourish. The story of life’s decimation at this point, followed by its resurrection, has multiple lessons for our own predicament.

The Capitan Reef, though long dead, once thrived between 272 and 260 million years ago in the middle of the Permian period, just before the greatest mass extinction the world has ever known. The International Union of Geological Sciences has selected three points within the park as “golden spikes,” the standard against which all other rocks of the Middle Permian period are compared. (The actual markers that indicate these points are brass plaques.)

At the bottom of the trail up to the reef one day, I met Guadalupe Mountains National Park geologist Jonena Hearst. After she patiently
answered questions from a park visitor and showed me some maps and geological charts, a process that took twenty minutes, she loaded up her day pack and lifted it onto her back. With a big broad smile she signaled it was time to get going. I followed after her. It was fall, a transitional time in West Texas weather, when mornings bore the chill of impending winter, yet the afternoons carried a remembrance of summer heat. McKittrick Canyon before us cut a slash through the Guadalupe Range, exposing the backbone of the Capitan Reef—one of the most extensive fossil reef formations on earth.

The surrounding terrain was dry, open desert, with cactus and creosote brush sheltering an assortment of rabbits, snakes, and lizards—a marked contrast from the tropical rain forests of Vilcabamba. Whereas the rain forest is full of moisture and life, the desert is bashful about any display of exuberance. Farther up McKittrick Canyon, cottonwoods surrounded a portion of the stream that surfaced intermittently. The trees were full of inviting autumn colors, but our path quickly pulled away from the stream and veered up a steep embankment toward the Capitan Reef above us.

What we saw of the reef exposed here displayed the calcified remains of an enormous formation of shelled creatures and sponges that once lay beneath an ancient sea, not unlike the coral reefs of today. A huge fault lifted a section of the reef high into the air, brandishing the dark rock for all to see. The trail was steep—a gauntlet of narrow switchback turns, full of slippery boulders that tested one’s stamina and balance. Yet the site was still quite popular, particularly with geologists and paleontologists, for it led into the fossil remains of an ancient world.

Park geologist Hearst was the keeper of this treasure, and was astute and knowledgeable about its intricate secrets. But she was as exuberant as she was scholarly. She told me she had last hiked up this reef just two weeks earlier, yet she wore a big smile despite some heavy breathing. “It’s a geological Disneyland,” she proclaimed. “Every time I go up there, I learn something new. How many times have I been on that ride, you ask?” She shook her finger toward the reef. “Don’t know, but I want to do it again!”

The hike began at the bottom of an
enormous depression known as the Delaware Basin, which spread out into Texas. The reef had formed over a distance stretching many miles around the lip of the basin, the horseshoe mouth of which once pointed out to an ancient sea. A quarter of a billion years ago, this reef was still glowing with a halo of life formed by millions of juvenile fish and other marine creatures that once used the nooks and crevices of the reef to avoid large predators.

Back then, two enormous continents—Laurentia (made up of North America, Europe, and Asia) and Gondwana (made up of South America, Africa, Antarctica, and Australia)—formed the terrestrial landscape at the surface of the planet. These two landmasses were on a collision course, soon to form Pangaea, the single continent that would take the world through the Permian extinction, an event that came the closest to ending life on earth than at any other time in the last 600 million years.

Our trail told the grand story of life before that event. We scrambled up the loose rock beneath the slopes of the giant reef head. We gained altitude quickly as the trail rose above the desert landscape. This was a deepwater reef, different from the shallower coral reefs most recreational divers are familiar with today. In Permian times, we would have been walking 5,000 feet (1,500 meters) below the surface of the ocean. “A very long snorkel to get to the top,” said Hearst.

As we rose upward, larger boulders and layered outcrops gradually displaced the loose, rocky slopes. Hearst stopped before a large boulder that reached our height and stared at the markings on it. At first I didn’t see anything special; it was just a big boulder. But then she pointed out the many fossils contained in the rock. It turned out that we weren’t staring at a plain rock—we were gazing on the calcified remains of ancient reef animals that had once been bound together in a mass of life.

During the Permian period this gallery of life included flowerlike crinoids, which sat atop stalks attached to the seafloor, their numerous tentacles coated with mucus extended out to capture prey, and
you could see the fossil remains of these creatures in this rock. There were also bryozoans, small animals that superficially resembled corals, which grew in tightly packed colonies resembling intricate fans, lacy fronds, or fruitlike displays that accumulated into massive stony buttresses. Also here were clamlike creatures called brachiopods, which were filled with a tangle of filaments that helped the animal sift food from the water but which would have made a poor clam chowder. There were numerous species of sponges as well as nautilus-like creatures housed in large spiral shells. The boulder was filled with such animals, surrounded by algae, which acted as cement to hold everything together. As she pointed to other rocks nearby, my astonishment grew. All the boulders housed similar amazing displays.