Over at the New York Times Opinionator website, writer Richard Conniff has been doing a pretty interesting series of columns on the early naturalists’ search for new animals and plants, “The Species Seekers“. Yesterday he wrote his final installment, “How species save our lives.” Conniff makes a good point, and one not widely appreciated: nearly half of the drugs on pharmacy shelves are derived from naturally occurring species, either directly or via synthesis of compounds identified from nature. Conniff mentions aspirin (from the willow tree), the cancer drugs vincristine (from the Madagascar periwinkle) and Taxol (from the yew tree), ACE inhibitors for reducing blood pressure (from snake venom), and the immunosuppressant rapamycin (from a soil fungus).
And indeed, it’s worth our trying to publicize these facts, which aren’t widely known, as a powerful argument for conservation. As Conniff says:
Since this is the final column in this series about how the discovery of species has changed our lives, let me put it as plainly as possible: Were it not for the work of naturalists, you and I would probably be dead. Or if alive, we would be far likelier to be crippled, in pain, or otherwise incapacitated.
Who knows how many potential cures lie undiscovered in tropical rain forests, or have already vanished? And yet I find myself vaguely dissatisifed with “selling” conservation in only this way. (Medical advance is the only conservation benefit that Conniff mentions in this final column.) Yes, maybe it’s politically expedient to concentrate on the ways that new species could make us healthier and (for the drug companies) wealthier. But what about the more intangible benefits of nature: the simple fact that it’s there, that it provides us with solace and wonder, and that so much we of what we know about evolution and ecology rests directly on studying animals, plants, and microbes in the wild. How much poorer we’d be had Darwin not acted as unofficial ship’s naturalist on The Beagle!
As I always tell my classes, humans are wondering animals, and scientists and naturalists help feed that wonder. But we can’t do it without nature: otherwise we’d be reduced to studying cockroaches and our own intestinal flora. The study of nature tells us where we come from and to whom we’re related, and provides a myriad of tales—true tales—to feed our imagination. I’m going to talk about some today in my evolution class. The lecture is on the phenomenon of mimicry, in which animals and plants evolved their appearance, scent, and behavior to resemble something else, either to protect themselves from being eaten or to hide themselves from prey. Here’s one of my slides—some katydids of the genus Mimetica, from South America, which have evolved to resemble leaves, complete with stems, veins, and even “rotten spots” (click to enlarge):
And here is a jumping spider (on bottom of leaf) that mimics
army weaver ants (on top). Note the astonishing resemblance, with the spider having evolved color, body shape, and fake eyespots to resemble those of the ants. It even holds up its front pair of legs (notice that the spider has eight legs, in contrast to the ants’ six), to look like antennae. The spider’s appearance almost certainly evolved via natural selection to give it protection from predators like birds, who avoid the swarms of ants. It’s amazing what that blind, mindless, and unguided process can do.
Evolution and ecology have given us thousands of tales like this—and they’re not just isolated anecdotes, for they feed into powerful scientific theories. It was the accretion of anecdotes, after all, that inspired Darwin to propose his theory of evolution by natural selection. And work on mimicry, in the late 19th century, provided some of the most powerful and telling evidence for natural selection. Let us not forget that the early naturalists weren’t much interested in the practical or medicinal value of species, but were inspired largely by that driving force of science, simple curiosity. It is that curiosity, expressed in both author and reader, that has rightly made Richard Dawkins a best-selling author. His books are about the beauty and marvel of evolution, and barely say a thing about its practical benefits.
So much of our interest in nature is selfish: how can it make us richer or healthier? And thus the practical appeal of conservation. But it would have been nice for Conniff to at least mention that nature is a huge and engrossing book of true stories, and a page is ripped from that book every time a species goes extinct. What right do we have to defile nature’s library? Does our evolved big brain, and our ability to overcome nearly every other species, give us the right to wreak whatever havoc we wish on nature for our own benefit? What about those defenseless frogs, trees, and beetles?
Morality is evolving over time, so that many people now see it as immoral to cause needless pain in animals. We don’t use chimps in medical research if macaques will do, and won’t use macaques if mice will do. People are rising up against battery chickens. It would be nice if we could extend that morality to ecosystems as well, recognizing that they have a right to exist simply because their species are precisely as evolved as we are.