The Best American Science and Nature Writing 2014

by Deborah Blum

  In 2006 an American big-game hunter from Idaho shot and killed the first documented wild polar–grizzly bear hybrid, a mostly white male covered in patches of brown fur, with long grizzly-like claws, a humped back, and eyes ringed by black skin. Four years later a second-generation “pizzly” or “grolar” was shot. After hearing reports of the bears, Brendan Kelly, then an Alaska-based biologist with the National Oceanic and Atmospheric Administration, started to wonder which other species might be interbreeding as a result of a changing Arctic landscape.

  Snow and sea ice hit record lows in 2012, and the Arctic has warmed more than 3.6 degrees Fahrenheit since the mid-1960s, more than twice the global average.

  To gauge what kinds of effects these shifts were having on Arctic animals, Kelly teamed up with the biologist David Tallmon at the University of Alaska and the conservation geneticist Andrew Whiteley at the University of Massachusetts Amherst. The trio coauthored a seminal report for the journal Nature in 2010 that chronicled the hybridization that wildlife managers and First Nations communities had been seeing in the Arctic, including the mixing of beluga whales and narwhals, bowhead and right whales, Dall’s and harbor porpoises, hooded and harp seals, spotted and harbor seals, and North Atlantic minke and North Pacific minke whales, in addition to polar and grizzly bears. They also outlined the devastating effects the new genetic exchanges could have on biodiversity, such as parent species being driven to extinction or creating hybrids unable to survive in the environments they are born into.

  The scientific community at large quickly recognized that the genetic mixing wasn’t limited to animals in the rapidly changing Arctic. Today they’re finding it all over the place, in owls, petrels, squirrels, big cats, and wild canines.

  Between 2007 and 2009, researchers from several Australian universities caught fifty-seven hybrid blacktip sharks while doing routine marine surveys off the northeast coast of Australia. Genetic tests confirmed that they were crossbreeds of Australian and common blacktips. The result of several generations of interbreeding, they were found south of the tropical areas where Australian blacktips typically live.

  Elsewhere, scientists are discovering that hybridizing species are exchanging behavioral and physiological traits, not just physical ones. Mark Scriber is an entomologist and professor emeritus at Michigan State University who studies swallowtail butterflies. In 1999 he began noticing hybrids in northern ranges that could and were eating plants previously tolerated only by southern swallowtail species. He also discovered hybrids in the north whose emergence had been delayed by four or five weeks, so that they arrived too late to mate with the previous generation of butterflies and too early to mate with the next. They could mate only with each other, essentially creating a new species.

  These sorts of interactions are, in their purest form, a kind of evolution, points out Kelly. For millennia, wildlife was forced together and pushed apart as climate, ecosystems, and landscapes changed. During these periods of upheaval, genes flowed between animals, creating new species and driving others to extinction. But genetic mixing that frequently takes centuries now takes only decades or even years, because modern climate change is altering the earth so quickly and drastically.

  Regardless of the cause, Jim Mallet, an evolutionary biologist at Harvard University who has studied hybridization in European and South American butterflies, argues that we should let nature take its course. And while he isn’t completely alone in his thinking, most other scientists interviewed for this story were divided over whether to take action or let the interactions play out unimpeded. “My feeling is that hybridization is natural,” Mallet says. “It is the result of a mating decision by an individual, and different individuals have different desires and interests. You don’t want to label a mating decision as unnatural when it’s found in the wild.”

  Still, recent human-driven hybridization could have catastrophic results for species. “The climate warming that we have induced is closer to a meteor strike [for species] than to the gradual evolution of green plants,” says Kelly, who is now the assistant director of polar science for the White House’s Office of Science and Technology Policy. “We’re forcing change to happen so quickly that it is more likely to promote extinctions than provide adaptive responses.”

  Unnaturally speeding up the hybridization process can significantly affect biodiversity and the animals themselves. Pairings in which one parent species is threatened usually hasten its decline, though scientists aren’t certain why one set of genes wins out over the other, as Vallender has seen with blue-winged warblers surviving while golden-winged warblers die off.

  Across the continent, Eric Forsman, a biologist with the U.S. Forest Service, has watched closely while spotted owls, a threatened species in the United States, lose their tenuous foothold in the Pacific Northwest, in part because of interbreeding with newly arrived barred owls. Barred owls have expanded their range from their native Midwestern homeland to the Pacific Coast, likely due to wildfires and climate change. “One hypothesis is that because of warming temperatures, the forests of northern Canada expanded,” scattering woodlands across the Great Plains and creating a migration corridor, Forsman says. “That may have allowed barred owls to expand westward across what was once a physical barrier and into spotted owl territory.” What spurs the two species to interbreed isn’t well understood, says Forsman. It may be that since there are fewer of their own species to mate with, spotted owls pair up with the first owl they see—and that’s likely to be one of the many barred owls that have moved into the area. Most barred owls, meanwhile, continue to mate with their own species. The end result is fewer spotted owls.

  The more genetically similar two species are—in terms of chromosome numbers or reproductive proteins—the easier it is for them to reproduce. Dogs and cats, for example, or lions and lambs are just too different genetically to produce offspring. But even when interspecies pairing is successful, the hybrid offspring face a series of unique challenges. Just as a mule—a cross between a male donkey and a female horse—is usually sterile, many hybrids cannot reproduce and are therefore genetic dead ends, says Mallet. Others inherit traits from their parents that render them ill equipped to thrive or even survive. Polar–grizzly bear hybrids bred in captivity, for instance, can’t swim as well as genetically pure polar bears, which could pose grave risks in an ecosystem where ice sheets—the frozen platforms from which they hunt seals—are smaller and farther apart.

  One of the biggest debates is about whether hybrids should be eligible for legal protection, particularly if one or both parent species are threatened or endangered. Currently, the Endangered Species Act doesn’t address hybrids. The same goes for the International Union for Conservation of Nature’s Red List of Threatened Species. (Hybrids may often be unknowingly protected because they can be difficult to distinguish from their safeguarded parents.) The U.S. Fish and Wildlife Service drafted a hybrid policy in 1996 but ultimately decided not to approve it, says J. B. Ruhl, an environmental lawyer and expert in climate change and the Endangered Species Act at Vanderbilt Law School. The agency instead adopted a policy of dealing with these animals on a case-by-case basis. Neither a Fish and Wildlife Service press officer nor several conservation lawyers could name any hybrids currently protected by the agency.

  The problem, Ruhl says, is that the Fish and Wildlife Service’s current policy addresses individuals, while the real issue is populations.

  Scientists and conservation experts are split as to whether these legal policies should be changed to deal with the growing number of hybrids. Some see no value in keeping hybrids around at all. Stuart Pimm, a species extinction expert at Duke University, says that wiping out hybrids is the best way to protect threatened species—though doing so would be tricky, he admits. “An unfortunate aspect of all this is that hybridization is a major cause of species endangerment and disappearance,” he says. “This is not one of those circumstances where the choices are easy ones, but these hybrids are a threat
to many valued species.” Hybrids have value, too, argues Richard Kock, a conservationist and member of the IUCN’s Species Survival Commission. “We should see [hybrids] as holding genes, some of which represent original species and therefore are of value,” he says. “With modern genetic understanding, breeding back to an original genotype is not impossible. So they have a place in conservation.”

  Ultimately, how we deal with hybrids will be decided among lawmakers and wildlife managers, in courtrooms and at international meetings. “It becomes a value question,” says Kelly. “Do you like having a white bear that specializes in hunting seals in the ice? That’s what’s in peril.”

  NICHOLAS CARR

  The Great Forgetting

  FROM The Atlantic

  ON THE EVENING of February 12, 2009, a Continental Connection commuter flight made its way through blustery weather between Newark, New Jersey, and Buffalo, New York. As is typical of commercial flights today, the pilots didn’t have all that much to do during the hour-long trip. The captain, Marvin Renslow, manned the controls briefly during takeoff, guiding the Bombardier Q400 turboprop into the air, then switched on the autopilot and let the software do the flying. He and his copilot, Rebecca Shaw, chatted—about their families, their careers, the personalities of air-traffic controllers—as the plane cruised uneventfully along its northwesterly route at 16,000 feet. The Q400 was well into its approach to the Buffalo airport, its landing gear down, its wing flaps out, when the pilot’s control yoke began to shudder noisily, a signal that the plane was losing lift and risked going into an aerodynamic stall. The autopilot disconnected, and the captain took over the controls. He reacted quickly, but he did precisely the wrong thing: he jerked back on the yoke, lifting the plane’s nose and reducing its airspeed, instead of pushing the yoke forward to gain velocity. Rather than preventing a stall, Renslow’s action caused one. The plane spun out of control, then plummeted. “We’re down,” the captain said, just before the Q400 slammed into a house in a Buffalo suburb.

  The crash, which killed all forty-nine people on board as well as one person on the ground, should never have happened. A National Transportation Safety Board investigation concluded that the cause of the accident was pilot error. The captain’s response to the stall warning, the investigators reported, “should have been automatic, but his improper flight control inputs were inconsistent with his training” and instead revealed “startle and confusion.” An executive from the company that operated the flight, the regional carrier Colgan Air, admitted that the pilots seemed to lack “situational awareness” as the emergency unfolded.

  The Buffalo crash was not an isolated incident. An eerily similar disaster, with far more casualties, occurred a few months later. On the night of May 31, an Air France Airbus A330 took off from Rio de Janeiro, bound for Paris. The jumbo jet ran into a storm over the Atlantic about three hours after takeoff. Its air-speed sensors, coated with ice, began giving faulty readings, causing the autopilot to disengage. Bewildered, the pilot flying the plane, Pierre-Cedric Bonin, yanked back on the stick. The plane rose and a stall warning sounded, but he continued to pull back heedlessly. As the plane climbed sharply, it lost velocity. The airspeed sensors began working again, providing the crew with accurate numbers. Yet Bonin continued to slow the plane. The jet stalled and began to fall. If he had simply let go of the control, the A330 would likely have righted itself. But he didn’t. The plane dropped 35,000 feet in three minutes before hitting the ocean. All 228 passengers and crew members died.

  The first automatic pilot, dubbed a “metal airman” in a 1930 Popular Science article, consisted of two gyroscopes, one mounted horizontally, the other vertically, that were connected to a plane’s controls and powered by a wind-driven generator behind the propeller. The horizontal gyroscope kept the wings level, while the vertical one did the steering. Modern autopilot systems bear little resemblance to that rudimentary device. Controlled by onboard computers running immensely complex software, they gather information from electronic sensors and continuously adjust a plane’s attitude, speed, and bearings. Pilots today work inside what they call “glass cockpits.” The old analog dials and gauges are mostly gone. They’ve been replaced by banks of digital displays. Automation has become so sophisticated that on a typical passenger flight, a human pilot holds the controls for a grand total of just three minutes. What pilots spend a lot of time doing is monitoring screens and keying in data. They’ve become, it’s not much of an exaggeration to say, computer operators.

  And that, many aviation and automation experts have concluded, is a problem. Overuse of automation erodes pilots’ expertise and dulls their reflexes, leading to what Jan Noyes, an ergonomics expert at Britain’s University of Bristol, terms “a de-skilling of the crew.” No one doubts that autopilot has contributed to improvements in flight safety over the years. It reduces pilot fatigue and provides advance warnings of problems, and it can keep a plane airborne should the crew become disabled. But the steady overall decline in plane crashes masks the recent arrival of “a spectacularly new type of accident,” says Raja Parasuraman, a psychology professor at George Mason University and a leading authority on automation. When an autopilot system fails, too many pilots, thrust abruptly into what has become a rare role, make mistakes. Rory Kay, a veteran United Airlines captain who has served as the top safety official of the Air Line Pilots Association, put the problem bluntly in a 2011 interview with the Associated Press: “We’re forgetting how to fly.” The Federal Aviation Administration has become so concerned that in January 2013 it issued a “safety alert” to airlines, urging them to get their pilots to do more manual flying. An overreliance on automation, the agency warned, could put planes and passengers at risk.

  The experience of airlines should give us pause. It reveals that automation, for all its benefits, can take a toll on the performance and talents of those who rely on it. The implications go well beyond safety. Because automation alters how we act, how we learn, and what we know, it has an ethical dimension. The choices we make, or fail to make, about which tasks we hand off to machines shape our lives and the place we make for ourselves in the world. That has always been true, but in recent years, as the locus of labor-saving technology has shifted from machinery to software, automation has become ever more pervasive, even as its workings have become more hidden from us. Seeking convenience, speed, and efficiency, we rush to offload work to computers without reflecting on what we might be sacrificing as a result.

  Doctors use computers to make diagnoses and to perform surgery. Wall Street bankers use them to assemble and trade financial instruments. Architects use them to design buildings. Attorneys use them in document discovery. And it’s not only professional work that’s being computerized. Thanks to smartphones and other small, affordable computers, we depend on software to carry out many of our everyday routines. We launch apps to aid us in shopping, cooking, socializing, even raising our kids. We follow turn-by-turn GPS instructions. We seek advice from recommendation engines on what to watch, read, and listen to. We call on Google, or Siri, to answer our questions and solve our problems. More and more, at work and at leisure, we’re living our lives inside glass cockpits.

  A hundred years ago, the British mathematician and philosopher Alfred North Whitehead wrote, “Civilization advances by extending the number of important operations which we can perform without thinking about them.” It’s hard to imagine a more confident expression of faith in automation. Implicit in Whitehead’s words is a belief in a hierarchy of human activities: Every time we offload a job to a tool or a machine, we free ourselves to climb to a higher pursuit, one requiring greater dexterity, deeper intelligence, or a broader perspective. We may lose something with each upward step, but what we gain is, in the long run, far greater.

  History provides plenty of evidence to support Whitehead. We humans have been handing off chores, both physical and mental, to tools since the invention of the lever, the wheel, and the counting bead. But Whitehead’s observa
tion should not be mistaken for a universal truth. He was writing when automation tended to be limited to distinct, well-defined, and repetitive tasks—weaving fabric with a steam loom, adding numbers with a mechanical calculator. Automation is different now. Computers can be programmed to perform complex activities in which a succession of tightly coordinated tasks is carried out through an evaluation of many variables. Many software programs take on intellectual work—observing and sensing, analyzing and judging, even making decisions—that until recently was considered the preserve of humans. That may leave the person operating the computer to play the role of a high-tech clerk—entering data, monitoring outputs, and watching for failures. Rather than opening new frontiers of thought and action, software ends up narrowing our focus. We trade subtle, specialized talents for more routine, less distinctive ones.

  Most of us want to believe that automation frees us to spend our time on higher pursuits but doesn’t otherwise alter the way we behave or think. That view is a fallacy—an expression of what scholars of automation call the “substitution myth.” A labor-saving device doesn’t just provide a substitute for some isolated component of a job or other activity. It alters the character of the entire task, including the roles, attitudes, and skills of the people taking part. As Parasuraman and a colleague explained in a 2010 journal article, “Automation does not simply supplant human activity but rather changes it, often in ways unintended and unanticipated by the designers of automation.”