Name Tags

On the strange evolution of taxonomy.


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It doesn’t take a scientist to know that an ostrich and an oriole
cannot mate. The two may share common traits: Each is covered with
feathers, and eats through a beak, and lays eggs. But the average
person knows it takes a lot more for two animals to get down to the
birds and the bees, so to speak.

  • Naming Nature: The Clash Between Instinct and Science by Carol Kaesuk Yoon. 352 pages. W.W. Norton & Co. $27.95.

Anyone can look at these animals and see two species that are simultaneously related and distinct. And most know the reason behind such duality — it’s evolution, stupid. But while it’s easy to recognize evolution’s delineated products — the tiny, fast, and orange-breasted oriole; the bulky, flightless, and long-necked ostrich — the process itself is trickier to glimpse.

But consider the Monarch flycatcher. Found in the Solomon Islands, some flycatchers posses a chestnut breast. Others, on an island just a few miles away, are entirely blue-black. The birds otherwise look identical, are in fact considered the same species. But maybe not for much longer. In the August American Naturalist, four scientists led by Syracuse University biologist J. Albert C. Uy argue that they may be witnessing a division within the flycatchers. As is their habit across the animal kingdom, the males of the flycatcher species are combative when it comes to their sexual rivals. When the researchers presented males of each flycatcher color with taxidermic models of a like-colored competitor, they demonstrated aggressive responses — they saw these “fakes” as challengers. But when presented with a competitor of the different color, the birds failed to recognize the stuffed animal as a rival. That the differing flycatchers do not recognize one another as sexual competitors suggested to the researchers that they likewise do not consider each other sexual partners. That these flycatchers can still breed is irrelevant; what’s instead important is the fact they may not be mating. Because of a single amino acid difference behind the color variation, the flycatchers are potentially at a fork in the road, with the blue-blacks about to go one way, and the chestnut breasts the other.

If the flycatchers continue down the speciation path, the scientific name Monarcha castaneiventris will one day be unsuitable for both. Coming up with a new name won’t be a problem — new species are discovered and named every day. But according to Carol Kaesuk Yoon, a New York Times science writer and the author of Naming Nature: The Clash Between Instinct and Science, what that name means is a different story.

Histories of the field of taxonomy typically begin with Carl Linnaeus, and for good reason. In the 18th century, when both growing international exploration and a widespread public fascination with natural history resulted in a flood of new species, it was Linnaeus who said enough’s enough to the increasingly messy and nonsensical process of naming the world. As Yoon points out, the Latin name of one plant from the era translated as “A spiny American tree, in some ways resembling Acacia, similar to Vesling’s myrobalanus chebulae, with Ceratonia leaves in pairs on the pedicle, a silique with two valves, which is compressed, and horn-shaped or curved like the horns of snailshells or rams’ horns, or like a cat’s claws;” in other cases, a single species could have multiple names. To clean things up, Linnaeus developed the hierarchy well-known today, dividing the living world into a system of kingdom, phylum, class, order, family, and most familiar, genus and species (think Homo sapiens).

But though he stands as a towering figure in the history of science, Linnaeus was hardly a scientist as we define the role today. He was more attuned to his senses than to any kind of scientific method, a man famed not for his processes but for his perceptions. Yoon writes:

They were what allowed him, upon encountering an entirely new plant, a mysterious new flower, to sense immediately, without conscious thought, what other plant it seemed most like, what thing it bore the most fundamental resemblance to out of all the plants seen, smelt, tasted, and touched, in a lifetime of botanical obsession, even admist natural history’s growing chaos. It was his lush and potent sense of the living world that made the truth so starkly obvious that he might immediately say, Oh, yes, that’s a Laurus.

Taxonomy traveled a fairly rocky road over the next few centuries. First came Darwin and his idea that life changes, calling into question the very idea of a “species” — out the window went the idea that an ostrich was and is and always will be an ostrich; taxonomy accepted that any order of life should reflect its evolutionary nature. But as science fragmented into biology and chemistry and physics, fields strengthened by the seemingly objective processes and rules and numbers-rich data of its practitioners, taxonomy struggled with the fact that its members were instead using their guts — experienced, well-informed, and expansive guts, but guts nevertheless. In the 1950s, numerical taxonomy appeared: Computers would crunch the data on visual characteristics collected by researchers and group specimens based on similarity. In the ’60s, the ability to compare proteins and later DNA launched the chemical (and very much invisible to the naked eye) comparison of life. The most recent, and possibly greatest, change came by way a group known as cladists (from the Greek klados, meaning branch). They believe taxonomic groupings should comprise only evolutionary relatives. This sounds all well and good until you learn that, whoops, this means there’s no such thing as “fish,” that word having been arbitrarily applied to a host of distantly related species on the tree of life that just happened to swim in water.

For Yoon, the disappearance of fish was the straw that broke the Camelus bactrianus‘ back. For every gain in the appearance of objectivity, in moving toward what’s considered a true science, she argues, taxonomy lost that element that drove Linnaeus, and many taxonomists after him, and Yoon herself — she has a Ph.D. in ecology and evolutionary biology from Cornell, but was inspired as a child by the sensual experiences of exploring life in the woods behind her home. Here, I confess, I experienced a feeling of kinship with Yoon: Such experiences led me to also pursue the study of biology, albeit on a path that ended not at the Ph.D. level, but at the bachelor’s.

Yoon has evolution on her side, she argues. It’s called the umwelt — a German word, it refers to how one perceives the world. There’s ample proof, she says, to suggest that the ability to order and name life — using those gut reactions — is an evolved skill, one that enabled our predecessors to distinguish between an animal that was prey and one that was predator, between a berry that nourished and one that killed. Among the evidence is the fact that across cultures, nomenclature systems are strikingly similar in that they often use a two-name system (again, Homo sapiens, or Canada goose) and similar categorizations like shrub and vine. In studies of folk taxonomies of languages alien to them, research participants have been able to successfully guess whether a particular name is used for a fish or a bird, suggesting some universal understanding about how a fish or bird name should sound.

Perhaps the most compelling argument for the umwelt comes via those who seemingly lack one. Yoon cites several examples of patients who lose the ability to distinguish between living things in the wake of series illness or brain injury. For some, it manifests as misnaming — calling a walrus a clam, for example. Others would stare at pictures of living things and not know what to make of the images, or be asked what the word “parrot” means, but have no association. For all these people, inanimate objects posed no problem. It was life that tripped them up.

Yoon makes a convincing case for the umwelt, and it’s certainly an intriguing one. But then she starts advocating for the umwelt, for preserving its use as a vital link between humans and what she sees as the increasingly distant natural world. The planet’s biodiversity is under threat but nobody cares because we’ve lost our sense of the umwelt, she argues. Or, more actually, we’ve just replaced the ordering of life with the ordering and complex understanding of brands and logos and products, traded the woods for the local Wal-Mart. Nature is all around us, ready to be appreciated — she sites as one example the birds she saw in a tree on a Brooklyn street, among sidewalks and garbage cans and leashed dogs: Frankly, it’s pretty tired advice, as far as nature goes.

Her professional training as a scientist was a different story. This is how she describes her graduate lab:

My professor…was a thoroughly modern geneticist, but he had a soft spot in his heart for natural history and for organisms of all sorts…You might imagine that meant the lab was zoolike, with aquaria and cages full of squawking, skittering animals, but it certainly was not. You might think that, at the very least, it had the look of a natural history museum, with specimens, tagged and labeled, around the room. But it was nothing like that, either. It was a high-tech lab, thoroughly devoid of any sign of life. What you saw instead were rows of glass vials and bottles, tiny plastic tubes and machinery with lights flickering on and off, the room laced with stark black laboratory benches. There were no living things to be seen, because we had, all of us, essentially no need of actual animals to do our work.

This is not presented as a criticism of the lifeless laboratory, but as straight-up description — indeed, a few pages later she confesses a bias before admitting she finds laboratory work beautiful. But though it may not be criticism, it does acknowledge what I believe is at the heart of Yoon’s exploration of the clash of her subtitle, one that transcends this particular work of popular science: When it comes to the battle between science and instinct, where’s the middle ground between the two? Here, again, I found myself related to Yoon: As an undergraduate, an interest in the aesthetics and the animals and the plants and the whole interplay of the seaside led me into a National Science Foundation summer program for undergraduates. On a seaside. There, my visceral attachment to that particular environment was paired with a project that had me using forceps to glue individual algae cells to a glass tip, injecting them with a chemical solution, and then taking pictures with a microscope to better understand how plant cell walls are constructed. It was, to say the least, a match made far from heaven.

Yoon’s solution to the umwelt’s disappearance and our resultant detachment is not to find common ground between science’s ordering of life, and that which the individual experiences via his umwelt, but to embrace both. Instead of a new paradigm, we have the two that already exist. In conflict. But when it comes to the natural world, what lies between the clinical, disinterested nature of the lab, and the fawning, uncritical, and blanket appreciation of the nature lover?

I say this not as someone with the answer, but instead as one who’s long asked the question. • 4 September 2009