What Sex Can Teach Us About Our Energy Future
Simply being “efficient” isn’t enough.
Photo by Yuriko Nakao/Reuters
Living things are the most incredible machines, honed for efficiency by millions of years of evolution. Many of our most advanced technologies attempt to emulate them but, more often than not, our results are clumsy and inelegant. Airplanes and helicopters employ the same basic principles of flight as birds, bats, and insects, but they fall pathetically short. The delicate hummingbird hovers with breathtaking precision to dip its proboscis into a nectar-bearing flower and then, in an instant, wheels and darts away. The albatross glides inches over the ocean for hours on a trans-continental voyage with barely a flap of its wings, riding the whisper of updraft that rises from the water. The frigate bird stretches its wings wide to circle and climb on thermals and then, spotting a fish in the ocean below, folds them back and swoops in a sudden plunge.
Our advanced flying machines can certainly go higher and faster than birds, but they consume vast amounts of energy in the effort and are impossibly lacking in subtlety. Nature flies much more efficiently than technology.
One of the great hopes for our energy future is solar power, and we have applied our technological gifts to the design and manufacture of contraptions that can convert sunlight into electricity. But even the best minds on the planet with all the resources of modern science have yet to develop anything remotely as efficient as the lowliest plant. Plants are incredible solar factories that convert sunlight to sugar all day, every day, in places cold and hot, wet and dry. And they do it with virtually no waste, in complete silence.
There are times, indeed, when nature seems perfect: a cheetah in pursuit, an orchid flower receiving a bee, a towering redwood or a perfect tomato ripening on the vine. One response to this apparent perfection has been to conclude that nature is designed—the work of a creator. The truth is much more inspiring, of course, and this world of apparent perfection arose on its own, with no direction whatsoever, as the myriad consequences of evolution.
Natural selection constantly hones living things to the utmost efficiency within their environment. The speed of the cheetah is repeatedly tested by the prey that attempts to outrun it, the orchid flower is repeatedly tweaked to ensure that the right pollinators will continue to visit, and the ripe tomato is constantly perfected by the fruit-eaters to whom its sugary redness says, “Eat me, disperse me, fertilize me.” It is those with the most successful arrangement of traits—the fittest—that pass on their genes to the candidates of the next generation most abundantly. Natural selection has spent 4 billion years sorting the strong from the weak the fast from the slow and the productive from the unproductive—it is the great machine of efficiency. But natural selection is only part of the story of life. The other story is sex.
Sex is expensive, it is risky, and it requires two organisms—often three, in fact—to get together. It is a stunningly inefficient waste of time and energy, and it is extraordinarily dangerous. Most importantly, of course, in order to perform the fundamental task of transporting genes from one generation to the next, sex is completely unnecessary. And yet nearly all the big organisms on the planet go to great pains to couple.
As far as the expense of sex is concerned, consider the leatherback turtle. Here is an incredible animal, a relic of the age of the dinosaurs that grows to about seven feet in length and weighs in at 600 pounds or more. It glides through the oceans all over the world, snapping up squid from Greenland to Antarctica. But every summer, mature female leatherbacks do the oddest thing. They swim thousands of miles back to the tropics, to the very beach where they were born, and haul their cumbersome backsides inch by clumsy inch up onto the sand. They then dig a three-foot-deep hole in the sand with their flippers and lay their eggs. At the end of the laying period, their job done, they swim back to the other side of the world. That’s a very expensive trip.
To illustrate the dangers of sex, consider the peacock. Here is a bird that must be a very tasty morsel for any number of predators in the forest, so much so that it spends much of its life looking skittishly over its shoulder to avoid getting eaten. But at breeding time, the peacock throws all caution to the wind, displays an immense rosette of brilliantly colored plumage, and struts around the forest like it’s invincible. That’s a lot of risk to take on just to get laid. Or look at the male praying mantis. He fusses around, finds a suitable mate, does his best by her, and then how does she repay him? Right. She bites his head off. What about elephant sex? Eek. That can’t be risk-free. Or porcupine sex—ouch.
Plants epitomize the logistical problems presented by sex. Here are organisms that don’t move much, so their specialty is the threesome. They coerce all manner of beasts—mostly flying ones—to serve as go-betweens. The orchid family is particularly fantastic in this regard. Orchids use highly specialized couriers to transport their sex cells directly from the boy orchid organs on one flower to the girl orchid organs on another. The orchid flowers have all their glorious shapes and colors to attract the insect eye, not the human one. The insect reaches for the nectar; the orchid exchanges its gametes. Why do the plants go to all this trouble? Why do any of these life forms go to these (sometimes literal) pains?
Steve Hallett is an associate professor in the Department of Botany and Plant Pathology, Purdue University. He is the author of The Efficiency Trap: Finding a Better Way To Achieve a Sustainable Energy Future and, with John Wright Life Without Oil: Why We Must Shift to a New Energy Future, both from Prometheus Books.