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"Palumbi has hit upon...one of the most important but widely neglected issues of our time."—Edward O. Wilson
Evolution is not merely the process that ruled the rise and fall of the dinosaurs over hundreds of millions of years. It also happens rapidly, so quickly and so frequently that it changes how all of us live our lives. Drugs fail because diseases like HIV and tuberculosis evolve in a matter of months, neatly sidestepping pharmacology. Insects adapt and render harmless the most powerful pesticides in a matter of years, not centuries. While the ecological impact of human technology has been well publicized, the evolutionary consequences of antibiotic and antiviral use, insecticide applications, and herbicide bioengineering have been largely unexplored. In The Evolution Explosion, Stephen R. Palumbi examines these practical and critical aspects of modern evolution with a simple, yet forceful style that contains both an urgent message and a sense of humor.
From the Mountains to the Sea
We waited for the helicopter to find us, listening to it search above for a break in the clouds, thrumming uselessly up there above the fog layer, nearly close enough to touch but not close enough to see. The pilot must have turned and moved away, not knowing he was right on top of us, because we heard the rotors grow quieter as he searched for our small party farther along the misted ridge. Mike Hadfield was on the phone again, a cellular luxury on this Hawaiian mountain peak, calling Honolulu Airport to have the pilot turn back and look again for a place to land.
We'd been snail hunting in the last vestiges of the true Hawaiian cloud forests, searching out the remaining populations of a six-pack of species no one had seen for decades. Unique to the peaks and valleys of the sharp Koolau Range, we hiked along the razorback ridges, two thousand feet above the warm Pacific Ocean, drenched with mist and blown by winds that hadn't seen land since leaving South America. The snails lived in trees, calmly licking the mildew off leaf undersides and quickly evolving into a riot of different species found nowhere else on Earth. Having finally learned how to raise them in captivity, Mike could save these species from marauding predators like rats and imported cannibal snails, so we had come to find them and escort them from their dangerous ancestral homes. I had scrabbled along with Mike for hours searching for the rare grape-sized globes, and now we were ready for the pickup.
But getting home ourselves might be hard. Mountainslopes rose toward the three-foot-wide ridge like hands pressed together in prayer, fully carpeted by shoulder-high trees dwarfed by the thin soil and whipped by the perpetual wind. Clouds were constantly ripped over the ridgeline by roiling gusts, leaving their cold gift of mist on every surface. The snails loved it, the helicopter didn't.
Twice more the rotors came and went above the clouds, twice more we called Honolulu. We bushwacked to the only flat place we could find, a cropped shoulder of rock on the lee side of the ridge, and when the mists cleared for a moment, the pilot found us. "Impossible to land beneath the ridge," he told Honolulu, and he sat the machine delicately, still flying, straddling the ridge, one hundred sheer feet above us. "Hurry."
We swam up to meet him, breast-stroking through the tree branches like drowning swimmers. Cresting the ridge, we vaulted into the open doors, pushing the delicately wrapped boxes of snails in ahead of us. The helicopter rose a foot, and blew off the mountains toward home.
Any biologist can easily find such adventures in Hawaii, where unique species scatter like precious diamonds across the landscape. Thousands of plants and insects, hundreds of ocean species, dozens of birds, and scores of tree snail types—all restricted to the Hawaiian Islands—have fascinated students of the evolutionary process for a century. A riot of evolutionary invention, the species of Hawaii represent some of the most extraordinary examples of how species can change and diversify in the blink of an eye.
But despite this profusion, and our enthusiasm for the native ecosystems of the cloud forests, when Mike and I came down from the mountain and headed home, we passed an even bigger hotbed of evolutionary change, where the rapid evolution of the Hawaiian forests seems glacial in comparison. Nestled on top of a small pass between two old volcanoes—a pass paved by a four-lane highway and choked with commuter traffic—perches a pinkness that represents more evolutionary potential and more evolutionary danger than any seen in the mountains above it. The landmark pink hospital, Tripler Army Medical Center in Honolulu, bustles with modern medicine and coordinated public health, and if you want to find explosive evolution, you should look in a place like this. Here you will find tuberculosis that has resisted treatment, strep throats that have shrugged off erythromycin, and a chilling postoperative infection called methicillin-resistant Staphylococcus aureus that can slip into a recovery room and kill after surgery. AIDS patients arrive for checkups, each carrying with them a self-contained arms race between their immune system and HIV, a race that runs on evolutionary fuel, with a grim finish line.
All these powerful diseases are changed by evolution, and all have been reborn recently from the evolutionary cauldron stirred by our technological society. Tripler stands in crowded company—in fact, any hospital in Honolulu or the rest of the country would be as good a bet for finding the products of evolution. No hospital in the world can ignore drug resistance, and drug resistance is evolution come to life.
Farther seaward, toward the glittering Ewa reefs, among the commercial, agricultural, and military checkerboard called Pearl City, I visited another evolutionary monument, one known throughout the world because something happened there that shook the billion-dollar biotechnology and biopesticide industries. A watercress farmer in Pearl City performed an evolutionary experiment on an introduced pest called the diamondback moth. Thriving in a lush and brilliant green field, pasted between shopping malls and the rising mountain slopes, watercress grows like lightning. But this tasty crop also attracts insect pests. Applying the biological pesticide called Bt toxin year after year to his plants, this farmer accidentally selected a strain of moth never before seen—one more resistant to the deadly Bt toxin than anything else in the world. Almost all other pesticides had already been overcome by resistant insects, but Bt had not. In Pearl City, that record was broken, evolution happened, and the moth won.
Sea level finally stops my tour, the rhythmic waves bringing foam and sand roiling up Waimanolo Beach to my feet, pulling me gently seaward. Ironwood and coconut shade the sand, but I am not here for long and I want to feel the sun before it slips behind the very mountains I had just descended. This beach, deep with coral sand, consists of irregular shards of calcium carbonate created by tiny coral polyps and anonymous marine algae. The major reef-building coral in Hawaii has been found nowhere else in the world, building up genetic changes over many generations until it was unique, and if we look carefully we can still see this evolutionary clock ticking gently away on the reef.
But we humans have a talent for upping the evolutionary ante and accelerating the evolutionary game, especially among the species that live with us most intimately—our diseases, food, and pests. The same evolutionary process that made this unique coral sand squishing between my toes operates in Pearl City and Tripler and the farms of Kansas. But it is much faster in human hands than on the reef, and for reasons we can see if we look closely, we unleash explosive evolution just by going on with our daily lives, and we don't even know we have lit the fuse.
|Ch. 1||From the Mountains to the Sea||3|
|Ch. 2||Right Before Your Eyes||8|
|Ch. 3||The Engine of Evolution||37|
|Ch. 4||Temporary Miracles: The Evolution of Antibiotic Resistance||65|
|Ch. 5||The Evolution of HIV||95|
|Ch. 6||Poisoning Insects, and What They Can Do About It||131|
|Ch. 7||Biotechnology and the Chemical Plow||162|
|Ch. 8||Evolution All at Sea||184|
|Ch. 9||Are Humans Still Evolving?||207|
|Ch. 10||The Ecology and Evolution of Aloha||231|
|Sources and Suggested Reading||253|