Sunday, 31 December 2017

Guest Post: Linnaeus, His Taxonomy, And Its Subversive Underpinnings

There is no more thunderous prescient of doom than the flutter of tiny wings - hackenslash

A very good friend of ours once said that you've got to be a real asshole to quote yourself* but, sometimes, the best way to express a notion is via repetition. Besides, let's face it, I'm a bit of an asshole.

Now, given the usual output of this little corner of the interwebs, one might think that little snippet to be some pithy commentary on chaos theory, a theory dealing with non-linear systems - systems that display sensitivity to initial conditions. This theory is most famously mangled in that scene from Jurassic Park in which the eponymous 'butterfly effect' is explained with the direction a drop of water cascades down the hand in a series of trials.

However, when I originally wrote that, it was an expression of admiration for our guest today. Calilasseia is a bit like the bogeyman, the monster that creationist parents tell their children about when they misbehave. Formerly moderator of the creationism section of the now-defunct Richard Dawkins forum, Cali is known to unleash tactical discursive ordinance on a scale that creation scientists are furiously working on a metric to be able to measure in a desperate attempt to find some way to counter even a tiny portion of it. His depth of knowledge and understanding of a huge range of topics makes that a somewhat quixotic enterprise.

Regular readers will recall having met him previously, in his spectacular and utterly comprehensive demolition of creationist dreck concerning radiometric dating which, I'm sure you'll agree, is a thing of beauty.

This one is a particular treat, as it's one I asked for specifically. Some will recall an incident - almost two years ago now - in which the Natural Environment Research Council has requested submissions from the public for names for its brand-new £200m research vessel, and my reasoned and probably only serious defence of keeping the name that won the public vote, the RSS Boaty McBoatface. In that piece, we explored some instances of scientists having a bit of fun with naming things, an attempt to undermine the notion that giving a serious research vessel a silly name was somehow disrespectful. I also talked about a fun evening trapping and cataloguing moths in which a certain individual regaled us with some of his knowledge of humorous binomials (two names) from the annals of Linnaean taxonomy. That individual was, of course, the inimitable Calilasseia. 

Ever since that outing, I've wanted to have a bit of fun and explore some of this wonderful territory, just to show that science is not the dry and dusty edifice that some might suppose.

Cali has offered the following introduction to Linnaean taxonomy which, I know, many of you will enjoy as much as I did. It also serves as a beautiful debunking of the notion that taxonomy is based on similarity alone.

Ladles and jellyspoons, the Blue Butterfly.


I was requested to provide a contribution on this topic, and so, I’ve finally set out and done just that. In short, what follows is an attempt at a concise history of the taxonomic system Linnaeus bequeathed to the world, after years of scientific endeavour. But, we need to cover some elementary concepts, before exploring the interesting history of that taxonomy, and the reasons for that taxonomy taking the form it did.

Quite simply, those Enlightenment scientists whose remit centred upon biology, quickly realised that in order to make sense of living organisms and the behaviour thereof, the first task to be undertook, was to identify those organisms. The basic principle being, of course, that if you’re going to talk about something, it helps to know what you’re talking about.

Now, for some organisms, distinguishing between them, and assigning an identity thereto, isn’t really that difficult. Most people would have little trouble telling a human being apart from an elephant. There are enough conspicuous differences between the two, to render this exercise simple. But when other organisms are examined, that task becomes a good deal more difficult. For example, a botanist could place two species of dandelion in front of an audience, and that audience, unless it consisted of other trained botanists, would be unable to tell the two apart. Likewise, an entomologist can easily alight upon very similar looking beetles, whose identity can only be resolved properly by other trained entomologists.

In the case of the dandelions, I’ll have to let a trained botanist provide the examples, as botany isn’t a discipline I possess great expertise in. However, thanks to my spending time studying entomology, I can provide a ready example in the case of beetles, and one that’s accessible to anyone who is willing to go out looking for them in the UK, where they can be found. Here they are:

Those beetles, incidentally, aren’t the only two I could have chosen. The UK fauna alone has dozens of similar pairings to select from. Here’s two more, again from the UK fauna, though the one on the left chose to tuck its head out of sight when photographed – that is not the key difference between these two:

So, in a world littered with lookalike organisms, how do we tell them apart, and resolve the identity problem?

Linnaeus wasn’t the only biologist working on this problem at the time, though he happened to be a fairly prolific contributor to the solution. That solution comes under the heading of comparative anatomy. In short, the procedure is as follows:

[1] Dissect the specimens of interest minutely;

[2] Diligently catalogue all of the anatomical features alighted upon during said dissection, along with sizes, shapes etc;

[3] Note where some specimens exhibit differences in precise anatomical construction from others.

Since more conspicuously different organisms (e.g., humans and elephants) exhibit observable anatomical differences (in this case, even before dissection), the biologists of Linnaeus’ day reasoned that the same would be true for every species they encountered. As with everything else in the world of biology, application of this principle is actually a little more complicated than I’ve just described, and modern data, whilst largely upholding this principle and its applicability, also provides us with a small number of counterexamples. But, I digress.

Armed with this idea, Enlightenment biologists set about dissecting with gusto. Linnaeus himself was a prolific practitioner of the art. Courtesy of this labour, made doubtless even more laborious, by only having quill pens and ink as documenting tools, they did indeed find that the principle expounded above, was generally applicable, and that comparative anatomy would provide a reliable foundation upon which to base species identity. Remembering of course that those biologists were pioneers in the field at that time, and it’s thanks to them, along with a lot of subsequent scientists and their labours over 250 years, that we know as much as we do now. We had to start somewhere, and whilst early biologists were laying some groundwork for some time before Linnaeus and his contemporaries, the exercise only truly started to become systematic and planned, around the time Linnaeus was in his childhood. Though there was one step missing from the enterprise, which it fell to Linnaeus to provide with his own later work.

That missing step, was the very simple one, of providing names for all these organisms, once they were determined to have separate identities. Indeed, that’s part of the central function of language itself – to provide us with a means of knowing what we’re thinking about, or subjecting to discourse. But, as anyone familiar with the existence of colloquialisms should already be aware, that function is compromised somewhat in everyday usage. Words in a language can become associated with multiple meanings, thus generating a need to extract the intended meaning from context, an area which makes English particularly hard for non-native speakers to learn. This one-to-many mapping of words onto meanings is also associated with the dual problem (again, prevalent with woeful frequency in English), namely the mapping of many words onto one meaning, or the existence of synonyms.

Matters became far worse, from the standpoint of biologists, when one looks at the names that even fairly common organisms had acquired over time, some being burdened with literally dozens of regional folk names. And that was just in the UK. A similar situation presented itself right across Europe, with folk names in abundance clouding the picture, even for organisms that were well-known and well-understood by the standards of the era.

What those Enlightenment biologists wanted, was to avoid those issues, and find a means of bestowing names upon organisms, that were unique and unambiguous.

Enter Linnaeus.

Linnaeus, indeed, was, in effect, the first individual to codify this requirement. But he went further. He not only made it a requirement of his taxonomic system, that names should be unique and unambiguous, but that those names should be connected to the anatomical data on those organisms arising from all that dissection work. The names to be chosen were, wherever possible, to be descriptive.

This set of requirements, on their own, would have constituted a significant step forward for the era. But Linnaeus went further, and in doing so, made his system, for reasons I shall come to, ever so slightly subversive.

Having engaged in much dissection work himself, Linnaeus, and for that matter, other biologists of the era, were moving toward a conclusion, even if they were not openly voicing that conclusion in explicit terms. That conclusion, and a very subversive conclusion it was to prove to be, was that organisms with very similar anatomy, and very few differences, were to be regarded as more closely related to each other, in some sense, than organisms with greater differences. This idea, of relatedness of living organisms, and the subsequent expansion of that idea within Linnaean taxonomy (I shall explain more shortly), was, of course, to be a central feature in later biological work. Indeed, it is possible that if Linnaeus had started to move away from taxonomy, and start investigating possible reasons for that relatedness, we could have had that later work much earlier than was the case. But this was not to be: taxonomy was Linnaeus’ overriding remit, and whilst pursuing the business of founding a workable taxonomic system, he simply treated relatedness of living organisms as a useful brute fact. But that he considered the concept valid at all, despite being, courtesy of the era he lived in, and the absence of competing explanations, a de facto creationist, should be making some of the audience of this exposition smile particularly mischievous smiles.

So, Linnaeus decided to embody that concept, of relatedness of living organisms, into his taxonomic system. He did so by arranging for organisms to have a two part name (hence the term ‘binomial classification’). One part of the name, the species identifier, would be associated with the particular organism in question, whilst another part of the name, the Genus, would indicate that the organism belonged to a well-defined group of anatomically related species.

Linnaeus took this idea of grouping anatomically related organisms still further. Not only were species to be grouped together into a Genus, but different Genera were furthermore to be grouped into Families, the Families into Orders, the Orders into Classes, and so on. In short, Linnaeus’ classification system, contained within it, an inherent idea of a tree of life. Yet, despite this direct embodiment of the tree-of-life idea into his taxonomy, Linnaeus managed to escape from some of the more febrile attention that was to be heaped upon some of his successors.

At this point, it is necessary to take a slight tangential diversion, and comment upon some of the particulars of his system. One feature thereof being a bone of contention for many, amateur and professional naturalists alike, and that feature centred upon his language choice. Linnaeus chose, in a move that seemed eminently sensible to him at the time, for reasons shortly to be revealed, to base his system upon Latin and Classical Greek.

The curious at this juncture are almost certainly asking why this choice was made. That has much to do with history, starting with the fact that Latin and Classical Greek had been mandatory entry requirements for European universities for at least 500 years, at the time Linnaeus was working. Since these two languages had been considered essentials of academic discourse for so long by Europe’s scholars, this choice made sense from that standpoint alone.

Those wondering at the underlying reasons for that persistence of these languages within European academia, have to look a little bit farther back in history. The earliest universities to arise in Europe, had their foundations at least in part, as offspring of theological seminaries, some more directly tied thereto than others, and inherited those language requirements from that background. At that point in history, theological seminaries were, of course, pretty much exclusively controlled in Europe by the Roman Catholic Church, an organisation for which Latin was the official language of discourse, courtesy of its own historical roots, and which wielded a large amount of political power across Europe during the era of the foundation of the earliest universities.

Classical Greek was included in the requirements, for more historical reasons, centring upon the fact that the New Testament was written almost exclusively in Classical Greek (to be precise, a dialect known as Koiné Greek), and of course, study of the New Testament was an essential part of the business of those ancestral seminaries. That Greek dialect itself, became the language of choice for the earliest New Testament writers, courtesy of being the lingua franca of commerce in the eastern Mediterranean, especially after the conquests of Alexander the Great. Additionally, Classical Greek civilisation bestowed upon the nascent Western Civilisation of Europe, a wealth of other documents, from authors ranging from Homer to Aristotle and Plato. Understanding their output, was, of course, an essential part of the business of the newly founded universities, and thus, Classical Greek and its variants became, alongside Latin, a mandatory entry requirement for anyone aspiring to be a scholar.

However, those two languages didn’t only have prestige and tradition to support that choice. Both languages contain rich vocabularies, which are of immediate use to any enterprise requiring descriptive nouns or adjectives, and the new taxonomy Linnaeus was introducing, was most assuredly an enterprise requiring this. Additionally, both languages possess systematic grammar constructs, allowing names to be devised in a systematic manner with relatively little effort. Much of the heavy lifting has already been provided by the existence of regular noun declensions and verb conjugations, to name but two entities of utility value in this regard. Since Linnaeus was very definitely interested in systematic name generation, these features of Latin and Classical Greek almost certainly endeared themselves to him, and were to be considered similarly useful by his similarly educated scholarly successors.

Furthermore, choosing two ancient languages enjoying universal prestige across Europe, neatly sidestepped the thorny issues that would have arisen, had a different choice been made. Given that Europe could be politically tumultuous in Linnaeus’ day, and in some cases for reasons that strike the modern reader as utterly trivial and banal, the choice was a wise one at that time. Selecting Latin and Classical Greek, neatly avoided giving the more febrile pursuers of European geopolitics in that era, another excuse to run riot, and launch into actual warfare, as was frequently their wont.

But, a choice that made much sense in 1758 (the year of publication of the tenth revision of Linnaeus’ Systema Naturae), seems pretty quaint to the Internet generation. In no small part, because study of those two languages, once considered an essential part of the school curriculum across Europe, is now very much a niche area. The educated layman of the 19th and early 20th centuries, was, paradoxically, much better equipped to understand the rationale behind the Linnaean taxonomic system, than the educated layman of the 21st century. In an era where manned spaceflight, supercomputing and direct manipulation of the genome are all engineering realities, the minutiae of languages that were last in serious use 1,000 years ago, tend not to be high priority topics for study.

From the standpoint of appreciating Linnaeus’ work to the full, this is, of course, a cause for lament, not least because there is much of interest lurking in that taxonomic system. One source being, the increasing dawning upon biologists, that their cataloguing exercise is far bigger than Linnaeus and his contemporaries imagined it would become. Having succeeded in giving the world a means of identifying and naming species, Linnaeus et al launched biologists on the path that would lead them to discover the magnitude of the task at hand, and the numbers in question are truly intimidating.

The classic case, of course, is the insects. The numbers of insects alone is staggering to behold. Even if we confine ourselves to the “Big Five” orders, the numbers are as follows:

Beetles (Coleoptera) : 400,000 species known to science
Butterflies & Moths (Lepidoptera) : 200,000 species known to science
Bees, Ants & Wasps (Hymenoptera) : 150,000 species known to science
True Flies (Diptera) : 125,000 species known to science
Bugs & Allies (Hemiptera) : 80,000 species known to science

Bear in mind, in addition, that those totals are growing. A new beetle is described by scientists at the rate of one per day. For the Lepidoptera, a new species each week is added to the tally. In the case of the Hymenoptera, that’s about one every three or four days. This process – the addition of new species to the list - has accelerated in recent years, as previously inaccessible parts of the planet have fallen within relatively safe reach of scientists, who no longer have to contend either with daunting natural obstacles, or the woes arising from the inability of some humans to coexist. Places previously unexplored due to hideous endemic diseases or internecine political strife, are now within reach of any institution that can afford the air fare, and the literature has been expanding in tandem with this development.

Those numbers, point to a big problem taxonomists have faced. Even those rich vocabularies I cited earlier, that were such an attractive feature of Latin and Classical Greek, start to run dry when there’s a million species to find names for. That number looks set to grow even larger, with some estimates reaching as high as 100 million species by the time the cataloguing has finished, and that estimate does not include fossil organisms - these too have been added to the list, and new fossils merely add to the naming problem. For example, there are 17,000 species of trilobite fossil known to science, and all of them have had to be named. A problem that living organisms do little to mitigate, when you have, say, 55 species of similar looking dull brown Skipper butterflies to name, and you end up running out of ways of saying “dull brown with bent antennae” long before the end of the list.

Consequently, some lateral thinking has had to be pursued. Mythology was, even as far back as the time of Linnaeus himself, quickly plundered for somewhat oblique descriptive references, with attributes of mythological characters tied to the anatomy or behaviour of several species. A particularly humorous example from my standpoint being a South American butterfly, named Styx infernalis. It acquired this epithet because taxonomists struggled for a century to find a home for it in that big tree of life, courtesy of the fact that upon dissection, it presents itself as a sort of ‘parts bin’ special, with features that could have come from any of four different Families. We had to wait for DNA technology to resolve that one, and, no doubt as an indication of their frustrations, taxonomists labelled this unfortunate butterfly as they did – Styx being, of course, the fabled river to the Underworld of Greek mythology, leading to this butterfly’s scientific name translating loosely as “the butterfly from Hell”!

However, there’s not merely exasperation to be found in some of those names. Every human emotion has, at some point, influenced some taxonomic decisions, and one need look no further than Linnaeus himself for a particularly juicy example. Here in the UK, there are four moths belonging to the Genus Catocala, all of which are characterised by dull forewings, that fold over and hide brightly coloured hindwings when the moths are at rest. One of these, Catocala fraxini, characterised by light blue hindwings, has a workmanlike choice of name, fraxini referring to the fact that the larvae of this species feed on Ash trees, the Ash tree itself being Fraxinus excelsior.

The other three, however, are named Catocala nupta, Catocala sponsa and Catocala promissa – the words sponsa, nupta and promissa all being related to brides, marriage and courtship related affairs. What prompted this choice? Back in Linnaeus’ native Sweden, it was the custom at the time, for brides to wear red petticoats on their wedding night, to be revealed just prior to the newlyweds skipping upstairs to the conjugal bedchamber. Consequently, at least one eminent scholar on the subject, has suggested that Linnaeus may have been gazing upon some nubile young maiden through his window whilst working on these moths, and the ensuing fond daydreams filtered through into his taxonomy.

That coupling of underwing moths in the Genus Catocala, to names connected with our own dalliances, as it were, persists into modern times. When, in more recent years, moths belonging to the same Genus were found living in North America, these too acquired their own courtship related names – some apposite ones to mention being Catocala amatrix (Sweetheart Underwing), Catocala amica (Girlfriend Underwing), Catocala cara (Darling Underwing), along with some species named after various mythological or literary temptresses. Thus we have Catocala desdemona, Catocala delilah, and Catocala miranda, just to add to the fun, and for those who welcome the requisite inclusion of diversity, there is also Catocala sappho to add to the list.

The topic of humour in taxonomy, incidentally, is now so voluminous as to require an article of its own, but I shall pause to mention but one example, where a desperation for new names led to some very off the wall thinking – namely, the bestowing, by the author, of the following four names on some new fly species (read them out loud for best effect):

Pieza pi
Pieza kake
Pieza rhea
Pieza deresistans

You get the picture.


Yes, we see (see what I did there?)

Thanks very much, Cali. Always a treat.

For those interested in discovering more hilarious examples, there's a marvellous website that Cali has recommended.

And finally, regulars can expect to see two new entries into the FAQ section in the next few days dealing with two very common apologetic fallacies which Cali has dealt with in his customary style and which he has kindly consented to reproducing here.

Thanks for reading.

*One prolific member of the Dawkins forum, Scholastic Spastic, had this quoted in his forum signature. Apologies for the in-joke.