Evolving Thoughts

Happy birthday Linnaeus

In honour of Linnaeus’ 300th birthday, and to rescue him from the canard that he merely applied Aristotelian logic to biology, I offer up this essay on his view of classification and species. I do not think Linnaeus was an essentialist in the Mayrian sense – he nowhere specifies that species have essences, only that there are diagnostic descriptions or definitions that allow naturalists to identify species in the field or in museum collections. But I’m no Linnaean scholar, so if anyone has information to the contrary, let me know.


Not much is known about the early education of poor Swedish student named Carl Linnaeus.1 Born in 1707, Linnaeus died in 1770, the most celebrated Swede of his day. In 1761, he was knighted with the vernacular name Carl von Linné, and took the Latinized name Carolus Linnaeus. Linnaeus
was a medical student turned botanist, and trained in Holland where he published his first botanical works. Before Linnaeus, species were given all kinds of descriptive names, usually in Latin, up to ten
words or so long. Each author made up their own terms, and there was no real convention for referring to species. On Linnaeus’ account, both species and genera were fixed, real and known by definitions. He
apparently believed that the genus was more real that species, and he allowed late in life that species may occasionally arise, but only within genera, through hybridization. Some (e.g., Stafleu 1971; Mayr 1969, 1982) consider Linnaeus to be an essentialist regarding species. This was due to the fact that, unlike the medieval logical conception, for Linnaeus all species (at least in botany, zoology and mineralogy)
were infimae species. He attempted to provide a diagnostic definition for each species,
although his practice and adopted motto “In scientia naturali principia veritatis observationibus confirmari debent” (in natural science, the principles of truth ought to be confirmed by observation, Stafleu 1971) suggests that he was not firmly wedded to a priori essentialism.



In the Systema Naturae
(10th edn, 1759, p7, Linne 1956) Linnaeus proposed a system of five ranks under the summum genus of the Empire of Nature (Imperium Naturae):


Regnum (Kingdom),


Classis (Class),


Ordo (Order),


Genus,


Species,

the last three of which corresponded to the logical ranks of genus intermedium, genus proximam, and (infimae) species. He also added a subspecific category of Varietas, which was the logical individuum. Later taxonomic conventions added the ranks of Phylum between Kingdom and Class, and Family between Order and Genus, giving seven ranks.2 The philosophical notion of species was not entirely helpful in botany, so Linnaeus changed it a little. Instead of there being any number of subaltern genera, he made the scale of classes absolute, and instead of working downwards, he started in the middle (at the genus). Linnaeus’ ranks began at species, and these existed in genera. Hence, to name a species you needed to give the generic name and the species name. Humans are members of the genus Homo (or Man; according to Linnaeus, one of several3) and our species is called sapiens (the wise one)4. So in Latin our “name” is “the wise man”. Humans, under his initial system, are:

Animals (Regnum Animale),

Mammals (Classis Mammalia),


Primates (Ordo Primates),


Man (Genus Homo),


Wise or rational (Species sapiens).

What Linneaus did was to make species and genera fixed ranks. He established this universal system for the naming and classification of all organisms. There were, for example, various kingdoms – plants
(Plantae) and animals (Animalia). Each species had a street address (its generic name, or genus) and a street number (its species name, or epithet).5
Now, taxonomists (those who classify taxa, or groups of organisms6) could use a single and relatively simple system for their organisms, and all could agree on how to name them, and what to name.


Linnaeus was definitely a special creationist – that is, he believed that each species was created specially by God, and Haller famously said of him that he thought himself a “second Adam” (Ramsbottom 1938: 195n), and he personally said the “God creates, Linnaeus disposes”. He wrote:

“There are as many species as the Infinite Being produced diverse forms in the beginning.” (Species tot sunt diversae quot diversas formas ab initio creavit infinitum Ens, Fundamenta botanica No. 157, 1736).

However, in 1744 he was forced to allow that some species are the result of hybridization, at least in plants, because he thought he observed it happening. A species of plant he placed in a genus Peloria (from the Greek pelor, meaning monstrosity) was in stem and leaf
structure part of the Linaria genus, but the flower was clearly different (Hagberg 1952: 196f; Glass 1959a). This admission was widely known by subsequent writers (e.g., Lee 1810; Gray 1821).
Still, he thought that genera were real and the possibilities for change limited. According to Larson (1967), Linnaeus imagined in the Fundamenta fructifications “that God created one species for each natural order of plants differing in habit and fructification from all others. These species, mutually fertile, gave birth to as many genera as there were different parents, their fructification somewhat changed” (p317).


In the Pralectiones (1744), Linnaeus went further:

The principle being accepted that all species of one genus have arisen from one mother through different fathers, it must be assumed:




  1. That in the beginning the Creator created each natural order only with one plant with reproductive power.



  2. That by their various mixings different plants have arisen which belong to the mother’s natural order as they are similar to the mother with regard to their fructifications, and are, as it were, species of the order, i.e., genera.


  3. We may assume that plants have arisen within the orders, i.e. by genera of one order, may mix with each other. In this way there will arise species that should be referred to the mother’s genus as her daughters. [quoted in Larson, loc. cit.]


Linnaeus thus employed the Great Chain of Being in a rather unusual way. Most “chainists” accepted what was later called the Principle of Plenitude (the lex completio), which stated that God would create everything that could be created, since he would not make an incomplete creation (Lovejoy 1936; Glass 1959a). This usually meant that species graded into each other is a series of varieties.
Linnaeus instead represented species using the metaphor of countries adjoining each other (in the Philosophia botanica §77). In his early writing, all the territory is pretty much filled – as he said, nature does not make jumps – but the countries are discrete and distinct from one another. In the later work, this strict fixism of the first edition of the Systema Naturae has been modified. All hybrids did was fill in a rare empty bit of territory in God’s time and plan. The borders were set by the genera, and all genera arose from a single species created by God. At the end of the 1750s, says Hagberg (1952: 199), Linnaeus was in a state of perplexity with respect to species. In 1755, he published Metamorphosis plantarum, dealing primarily with the development of plants, but also with monstrosities and varieties. Such later hybrids he called the “children of time” in an anonymous entry in a competition at St Petersburg in 1759 (Hagberg 1952: 201f), and also in the Species plantarum (1753, 2nd edition 1762-63), where he speculated that a species of Achillea (yarrow, or staunchweed), alpina, might have formed from another, ptarmica, “[an] locus potuerat ex praecedenti formasse hanc?” (“Could this have been formed from the preceeding one by the environment?”, in volume II, 1266 of the second edition, quoted in Greene 1959: 134). Hagberg says, “Linnaeus never succeeded in pin-pointing his new
conception of species. But the old one, that formed the basis of Systema Naturae, was utterly and irrevocably abandoned.”


Moreover, Linnaeus also noted that species grew differently according to the conditions of their locale. Of the genera Salix, Rosa, Rubus, and Hieracium, (willows, roses, brambles, and hawkweeds), Linnaeus said that their description was problematic
because of variability (“metamorphosis”) of form in different soils and climates (Ramsbottom 1938: 200f). Habitat-induced variability will become an issue under Göte Turesson’s
investigation in the early 20th century (see below). Linnaeus also experimented on propagating a hybrid geranium, with success, in 1759 (Ramsbottom 1938: 210f); he believed that maternal influences of
hybrids affected the “medullary substance” and fructification of plants, but the leaf structure was due to the paternal species As time went on, he removed the statement that there were no new species
from his 1766 edition of the Systema Naturae, and crossed out the statement natura non facit saltum from his own copy of his Philosophia Botanica. A full account of Linnaeus’ various pronouncements on species can be found in Ramsbottom (1938).


When Linnaeus was working, European trade and exploration was limited. Linnaeus himself classified around 6,000 species of mainly Mediterranean and northern European plants, and later animals (Stafleu 1971). This was more than had been done before, but still it was a fraction of what we know today. His students and adherents sent him specimens from around the world, and there was a steady “trade” in
specimens between him and other taxonomists and collectors (Müller-Wille 2003). Linnaeus hoped that his system would enable taxonomists to list all actual species, but he also knew that his system was artificial – that is, not the pure result of studying the actual characters of organisms, but also imposing an a priori scheme on them for convenience. He hoped there would be a “natural” scheme developed on the basis of an aggregation of characters, but he was never able to do more than a partial sketch of one. In his later work, he set up a “rational” system that allowed for there to be
3,600 genera in plants, each of which could generate species through hybridization. Although this was supposed to be a “natural” system (one based on the closeness of resemblance of all traits of the organisms and not just a single character), in fact he chose just three features of plants and restricted the varieties to 60 types of each (hence 603 = 216,000 maximum of plant species). However, this was fragmentary and in an appendix, and not developed further.


In summary, Linnaeus proposed a five rank taxonomic system, and there were only a set number of species possible, although later he was forced by various observations, including his own, to accept that new species could be created through hybridization. All that remains of his taxonomy are the names and general ranks of his system, but even this has been dramatically modified, with such groups as tribes,
sub-families, and so on being added to deal with the massive increase in species discovered since.


Linnaeus distinguished between the diagnostic characters (characters) and actual traits (notae) of organisms, but it seems not much came of this distinction. He appears to have despaired of a natural system in his foreseeable future, and so promoted a purely diagnostic and hence conventional taxonomy, even though he believed that species were themselves natural, along with genera. This tension underlies much of later taxonomy.


Notes


1 I am informed by Staffan Müller-Wille (pers. comm.) that Linnaeus, being from a relatively poor district of Sweden, Småland, known (presumably by an Englishman) as the “Scotland of Sweden”, was taught from old standard textbooks, and not out of the neo-Platonists early or late, as far as is recorded (see also Frängsmyr 1983; Koerner 1999; Goerke 1973). According to Hagberg (1952: 44ff), he was greatly influenced by Aristotle’s Historia Animalium as a young student.



2 According to the Oxford English Dictionary, phylum is a term first coined by Cuvier, in Regne Animal (1817), to cover his four embranchements, later adopted and made popular by Ernst Haeckel. Family is most probably Adanson’s term (Judd et al. 1999: 40). The Strickland Code of 1842 (Strickland et al. 1843: 119) mentions “families”, noting they ought to be ended in -idea, and this implies families were in common use by that time. It also allows subfamilies. Mayr, Linsley and Usinger (1953: 272) give the introduction of “family” to Latrielle in 1796, but do not give any information regarding phylum. In botany, phylum is not used, and instead the rank is division, probably introduced in Alphonse de Candolle’s 1867 Rules submitted to the Paris meeting that year of the International Botanical Congress. The present International Code of Zoological Nomenclature does not regulate higher taxon ranks above superfamily (Winston 1999: 32), and so phylum is in effect an informal rank. Recent attempts to revise the rank of kingdom and add empire, or domain (Woese 1998; Syvanen and Kado 1998; Margulis and Schwartz 1998; Williams and Embley 1996; Baldauf, Palmer, and Doolittle 1996) are thus legitimated by tradition even if not widely accepted.

Late note: I just found a copy of De Candolle’s “lois”, or laws of botanical nomenclature via Gallica ((bless the Biblioteque Nationale!) and yes, it was there these terms were introduced, but it was accepted in 1868, not ’67. “Phylum” was, I recall, instroduced to zoology in the 1870s.


3 Huxley describes the initial history of hominoid classification, and notes that while there had been some excellent descriptions of orangutans and chimpanzees in the 18th century, Linnaeus relied on second-hand sources, and classified four species under the genus Homo: Under the specific epithet of troglodytes, he combined the prior “species” of Homo sylvestris (probably a juvenile chimp), and Homo nocturnus (a badly-represented orangutan) (cf. Huxley 1906: 10-13) in the 1758 (tenth edition) Systema naturae (p25), apart from Homo sapiens. Huxley also lists Homo caudatus (a cat tailed ape, either mythical or a misunderstanding of a description of a baboon), but by the tenth edition at least, this was no longer in evidence. It is occasionally noted that by the established rules of nomenclatural priority, chimpanzees should therefore be included in Homo on Linnaean grounds as well as on cladistic grounds (which is argued in, for instance, Diamond 1991). However, troglodytes explicitly mentions the Orangutan in the Systema Naturae, while the chimp is more likely to be Simia satyrus, in another genus altogether (p25).



4 It is sometimes thought that sapiens means “the knowing one”, but a check of various Latin dictionaries of the Latin of the time and earlier indicates that it means “wise” or “sage”.



5 In modern practice, the genus name is always capitalized and the species epithet is always lower case, and both are always italicized. Other taxonomic ranks are capitalized but not italicized.



6 According to Mayr (1982: 870n), the term taxon was proposed in 1926 by Meyer-Abich (see also Lam 1957, who discusses the term in more detail, noting that it is a nomenclatural term for a phylogenetic group). Hence in this context it is an anachronism. Stafleu notes that Linnaeus’ own general term for taxa was phalanx, but that it did not catch on.


References

Baldauf, S.L., J.D. Palmer, and W.F. Doolittle. 1996. The root of the universal tree and the origin of eukaryotes based on elongation factor phylogeny. Vol. 93: Proc Natl Acad Sci U S A.

Diamond, Jared M. 1991. The rise and fall of the third chimpanzee. London ; Sydney: Radius.

Frängsmyr, Tore, ed. 1983. Linnaeus, the man and his work. Berkeley: University of California Press.

Glass, Bentley. 1959. Heredity and variation in the eighteenth century concept of the species. In Forerunners of Darwin, 1745-1859, edited by B. Glass, O. Temkin and W. L. Straus Jr. Baltimore: Johns Hopkins Press.

Goerke, Heinz. 1973. Linnaeus. New York: Scribner.

Gray, Samuel Frederick. 1821. A natural arrangement of British plants: according to their relation to each other, as pointed out by Jussieu, De Candolle, Brown, & c. including those cultivated for use: with an introduction to botany in which the terms newly introduced are explained. London: Baldwin, Cradock and Joy.

Greene, John C. 1959. The death of Adam: evolution and its impact on Western thought. Ames: Iowa State University Press.

Hagberg, Knut. 1952. Carl Linnaeus. Translated by A. Blair. London: Jonathan Cape.

Huxley, T. H. 1906. Man’s place in nature and other essays. Everyman’s Library ed. London; New York: J. M. Dent/E. P. Dutton.

Judd, Walter S., Christopher S. Campbell, Elizabeth A. Kellog, and Peter F. Stevens. 1999. Plant systematics: A phylogenetic approach. Sunderland MA: Sinauer Associates.

Koerner, Lisbet. 1999. Linnaeus: nature and nation. Cambridge, Mass: Harvard University Press.

Lam, H. J. 1957. What is a taxon? Taxon VI (8):213-215.

Larson, James L. 1967. Linnaeus and the Natural Method. Isis 58 (3):304-320.

Lee, James, 1715-1795. 1810. An introduction to the science of botany: chiefly extracted from the works of Linnaeus; to which are added, several new tables and notes, and a life of the author / by … James Lee. 4th ed., corr. and enl. / by James Lee, son and successor. ed. London:: Printed for F.C. and J. Rivington; Wilkie and Robinson; J. Walker …,.

Linne, Carl von. 1956. Caroli Linnaei Systema naturae: a photographic facsimile of the first volume of the tenth edition (1758): regnum animale. London: Printed by order of the Trustees, British Museum (Natural History).

Lovejoy, Arthur O. 1936. The great chain chain of being: a study of the history of an idea. Cambridge, Mass.: Harvard University Press.

Margulis, Lynn, and Karlene V. Schwartz. 1998. Five Kingdoms: an illustrated guide to the phyla of life on Earth. 3rd ed. San Francisco: W.H. Freeman.

Mayr, Ernst. 1969. Principles of systematic zoology. New York: McGraw-Hill.

——. 1982. The growth of biological thought: diversity, evolution, and inheritance. Cambridge, Mass.: Belknap Press.

Mayr, Ernst, E. Gorton Linsley, and Robert L. Usinger. 1953. Methods and principles of systematic zoology. New York: McGraw-Hill.

Müller-Wille, Staffan. 2003. Nature as a Marketplace: The Political Economy of Linnaean Botany. History of Political Economy 35 (Annual Supplement):154-172.

Ramsbottom, John. 1938. Linnaeus and the species concept. Proceedings of the Linnean Society of London 150 (192-220).

Stafleu, Franz Antonie. 1971. Linnaeus and the Linnaeans. The spreading of their ideas in systematic botany, 1735-1789, Regnum vegetabile, v. 79. Utrecht,: Oosthoek.

Strickland, Hugh. E., John Phillips, John Richardson, Richard Owen, Leonard Jenyns, William J. Broderip, John S. Henslow, William E. Shuckard, George R. Waterhouse, William Yarrell, Charles R. Darwin, and John O. Westwood. 1843. Report of a committee appointed “to consider of the rules by which the nomenclature of zoology may be established on a uniform and permanent basis”. Report of the British Association for the Advancement of Science for 1842:105-121.

Syvanen, Michael, and Clarence I. Kado, eds. 1998. Horizontal gene transfer. Boston: Kluwer Academic Publishers.

Williams, David M, and T. Martin Embley. 1996. Microbial diversity: domains and kingdoms. Annual Review of Ecology and Systematics 27:569-595.

Winston, Judith E. 1999. Describing species: practical taxonomic procedures for biologists. New York: Columbia University Press.

Woese, C. R. 1998. Default taxonomy – Ernst Mayr, view of the microbial world. Proceedings of the National Academy of Sciences of the United States of America 95 (19):11043-11046.

Comments

  1. #1 justawriter
    May 21, 2007

    Cool, a post from the future. Can you tell us how the basketball playoffs turn out?

  2. #2 coturnix
    May 21, 2007

    Who won Belmont Stakes 2008?

  3. #3 John Wilkins
    May 21, 2007

    Rickin rackin Ecto-Moveable Type interface. It’s supposed to be scheduled. Oh well, it’s there now…

  4. #4 ERV
    May 21, 2007

    Linnaeus also mused on the idea of a ‘flower clock garden.’ He never got around to planting one himself, but Truman State recently created a kick-ass clock garden/sundial hybrid.

    Flower opening times arent usually listed in gardening books, as it varies according to latitude, so it must have taken a wonderfully clever undergrad to help with such a project…**cough cough**

    hehehe!

  5. #5 AriSan in New York
    May 21, 2007

    Dear John Wilkins:
    You provided very timely info on ‘Linnaeus’ helping me save time to looking up on my own from scratch. Your main introduction and references are so very helpful at a time when I was just to embark on collecting info for my own need. What a good luck did land on my way! Thanks!

    Sincerely,

    AriSan

  6. #6 Torbjörn Larsson, OM
    May 21, 2007

    Thanks for the timely posting! I invite everyone over to Sweden to participate in the celebratory year. The Imperial Majesty Akihito is currently visiting.

    If you make it all the way up to Uppsala, where Linneaus established his system and were later buried, I can recommend the pastry at the coffee shop in the Linneaus Garden in the towns center. There are many more places to visit and much else to do, see http://www.linnaeus2007.se/ .

    Linnaeus had more apostles than the christian bible, 17 of them (see the above link). Their travels were mostly financed by new The Royal Swedish Academy of Sciences giving out a calendar – in lieu of good scientific intentions they had to give in and include the superstition of the farmers schedules of weather predictions.

    One apostle was Daniel Solander, traveling among the botanists that were first on Australia with James Cooks first voyage. 7 of the apostles died on the trip; one of those had bankrupted and his research material had to be bought free. (http://www.nyteknik.se/art/50437 ; in swedish.)

    being from a relatively poor district of Sweden, Småland, known (presumably by an Englishman) as the “Scotland of Sweden”

    AFAIK the similarities also goes to the entrepreneurial spirit, inventiveness and cooperation of the people and their small scale businesses.

    There is an old series of humor movies about an original inventor and his dog, … ehrm, excuse me, faithful friend, being a caricatured archetype from Småland. Yes, there are cars, rockets and Rube Goldberg devices. :-)

  7. #7 Thony C.
    May 22, 2007

    I have a question that I will address to both Mess’rs Wilkins and Larson. Linnaeus was Sweden�s most significant scientist in the 18th century in fact he was one of Europe’s most significant scientists in the 18th century. This fact was even acknowledged in his own lifetime in that he was granted a knighthood. This being the case, how come his Nachlass i.e. his natural historical collections and his papers were flogged off to the first Englishman who happened to pass by with a couple of quid to spare? Just curious!

  8. #8 Thony C.
    May 22, 2007

    Sweden�s should of course read Sweden’s

  9. #9 John Wilkins
    May 22, 2007

    According to this site his wife sold it after her son’s death, and James Edward Smith (a very well known botanist of the day) managed to buy it. But the myth that the King of Sweden sent a ship to chase the one carrying the collection to London is false.

  10. #10 windy
    May 22, 2007

    Great essay!

    An interesting additional tidbit is that “Peloria” is not really a new species or a hybrid, but a mutant form of Linaria vulgaris with a strange flower shape.

    http://www.springerlink.com/content/tp36336815147048/

    So the hybridisation idea was something of a red herring for Linnaeus in this specific case, although it turned out to be correct in other plant species.

  11. #11 John Wilkins
    May 22, 2007

    Yes; as I understand it, Peloria was an autopolyploid of Linaria. But Linnaeus thought it was a hybrid, and hybridisation was traditionally the mode for the generation of new species, as far back as Aristotle in the History of Animals.

  12. #12 windy
    May 22, 2007

    Yes; as I understand it, Peloria was an autopolyploid of Linaria.

    Actually some people recently suggested that it could be an epigenetic thing:

    http://www.nature.com/nature/journal/v401/n6749/full/401157a0.html

    But a Swedish botanist that has looked into Peloria thinks that this variant methylation pattern in the Lcyc gene depends on an ordinary DNA mutation. Either way, it seems to be dependent on a single gene and not polyploidy.

  13. #13 Thony C.
    May 22, 2007

    According to this site his wife sold it after her son’s death, and James Edward Smith (a very well known botanist of the day) managed to buy it. But the myth that the King of Sweden sent a ship to chase the one carrying the collection to London is false.

    The real question is why didn’t the Swedish government secure Linnaeus’ Nachlass for the nation?

  14. #14 John Wilkins
    May 23, 2007

    According to the biography I have by Knut Hagberg, which is generally pretty reliable, though under referenced, the collection was to be sold at Carl’s death, but his son managed to hang onto it by renouncing his claim to the estate. He died young, and so Carl’s wife contact Joseph Banks, who made an offer at Carl’s death, but Banks was not interested as he now had a large collection of his own. But Banks was dining with Smith, and mentioned it. Smith wrote to the executor, J. G. Acrel and made the offer. Hagberg notes:

    For some unaccountable reason, no one in Sweden was sufficiently interested to make a bid for the collections, and Smith energetically pushed forward the negotiations.

    Smith then went abroad, and when he returned two years later he got together with Banks and others to form the Linnean Society [note that they spelled Carl's name the way he spelled it after being knighted in 1761] in 1788. Smith had Linnaeus’ diary and correspondence translated and published.

    In 1858, Darwin’s paper was read before the Society, along with Wallace’s letter.

    I think it likely that governments generally did not fund scientific ventures much, outside France, at the time.

  15. #15 Thony C.
    May 23, 2007

    By one of those strange cases of sychronocity I visited the Department for the History of Medicine here at the University this morning, in order to extend a book that I had borrowed from their library, and whilst I was there, and the secretary was feeding my dog, I happened to notice the following book amongst the new acquisitions; From Private to Public: Natural Collections And Museums (Uppsala Studies in the History of Science) Ed. Marco Beretta. One of the papers is The Swedish Natural History Museum and Collections in the Linnean Tradition! There is also a paper on Charles Darwin as a collector that might be of interest to you. Unfortunately it hasn’t yet been catalogued and so I couldn’t borrow it, which I will definitely do at some point as it has several papers that are of interest to me.

    Thony C. FCD

  16. #16 Torbjörn Larsson, OM
    May 23, 2007

    I think it likely that governments generally did not fund scientific ventures much, outside France, at the time.

    Yes, AFAIK that was the reason The Royal Swedish Academy of Sciences sought “inventive financing”.

    Also, I am no student of history, but I think Sweden was pretty much dirt poor and under-industrialized between the days it was a superpower until the beginning of the 20th century. Remember the Småland description?

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