Living things are the most incredible machines, honed for efficiency by millions of years of evolution.
OPINION: 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, fertilise 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 four 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, 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 2m in length and weighs in at 270kg 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 kilometres 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 1m-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 epitomise 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 specialised 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 colours 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?
The answer is well known, of course: Sex is required to provide genetic variability. But what does "producing genetic variability" really mean? Well, it means that while natural selection is busying itself with the task of perfecting organisms for efficiency, sex is doing the exact opposite. It is busying itself with screwing them up.
The fact that sex is essential to long-term survival on this planet is self-evident. Any species that abandoned sex must have been eventually whisked into extinction.
Sex, then, is a system that shows phenomenal evolutionary foresight — it plans for the future — but that makes no sense, either. Evolution has no foresight whatsoever. It operates strictly on a generation-to-generation basis and has no idea what traits will be most successful in 1000 generations.
Sex is best seen as a regulating device that tempers the tendency of natural selection to ensnare species in an efficiency trap.
Unregulated, natural selection would repeatedly drive organisms to the highest level of efficiency, but it would also drive them to the highest level of simplicity.
The most efficient organism, a success in its environment, would out-compete less efficient individuals and natural selection would drive the less efficient organisms into extinction. Eventually, the most efficient individuals would be producing super-efficient identical clones of themselves, and these offspring would be successful, too — but only while the environment remained unchanged.
Super-efficient clones would benefit from the energy savings of abandoning sex in the short term, but they could never last.
Changes in the environment, such as decreased rainfall, increased temperatures, or lower humidity, might leave an organism high and dry in a place to which it is no longer well adapted.
Even more dangerous would be changes in an organism's food supply or adaptation in its predators and parasites.
Unable to respond to changing threats, super-efficient clones would lose their edge and find themselves vulnerable.
No longer able to evolve apace with the rest of the biological world, their eventual demise would be assured.
We seem to have great faith in the capacity of efficiency solutions to avert the confluence of environmental and economic problems we face.
The gathering storm of climate change, largely the consequence of burning fossil fuels, is intimately linked to our looming energy crisis as fossil fuel reserves decline.
These two wicked problems seem to have the same solution: Use fossil fuels more efficiently.
I'm sorry, but that's a short-term fix that merely clones a doomed experiment in the hopes that it can keep going a few years longer.
Much more valuable would be to develop a more diverse portfolio of energy sources, but the problem of efficiency looms here, too.
We seem to be trying to plug new energy sources into the centralised system that we developed and streamlined over the last century.
We're hoping for bigger, more efficient wind farms, solar arrays, and biofuel refineries.
If only we can make these (mostly) more benign energy sources more efficient, we say, our energy crisis can be averted.
Let's swap out the nasty hydrocarbons for clean, green alternatives. If only it were that simple.
Our ability to extract natural resources, to compete, to develop new technologies and to streamline our business develops apace: We become increasingly efficient. But our resilience erodes.
We lack checks and balances; we lose diversity and robustness; we find ourselves perfectly adapted to the world as it is. But what if the world should change?
To find our steady state and solve the sustainability puzzle our greatest needs are neither more energy sources nor more efficiency.
Rather, we need to abandon the delusion that growth is a measure of progress. Only progress in diversity and beauty can stand the test of time.
So relax, take it easy, spend more time with the one you love, and remember: The key to a sustainable future is sex.
The true genius of ecosystems is not their ability to keep growing and consuming, but to adapt, and more than one billion years after sex first evolved, it remains a requirement for long-term survival.
It is expensive, risky and cumbersome, but life on Earth has found through bitter experience that the surest path to extinction is to abstain from sex and fall into the efficiency trap.
The antidote for efficiency in the natural world is sex. We need to find similar antidotes to efficiency in the modern world.
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'.
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