Letter to the Editor 553
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LETTER TO THE EDITOR 553 LETTERTO THE EDITOR FIVE KINGDOMS-REFLECTIONS UPON THE CLASSIFICATION OF ORGANISMS "animalcules." For over the past 3 decades,there have been new world of Knowledge of these profound advancesin the classification of orga- microorganismshad progressedby the 1860sto nisms, both living and extinct. This is a matter the point where Ernst Haeckel commencedhis of central importanceto biology and biologists. Iengthy campaign to have them recognizedas a Surprisingly, the fact seemsto have escapedthe third kingdom of organizedbeings, the Protista "the notice of many of our more specialized col- (meaning very first"). leagues.Therefore, as the relevant taxonomic Well aware that Haeckel was also credited "oecology" changesclarify the true systematic position of with coining the word (although various aquatic microorganismsintimately con- Americans will be delighted to learn from VoL "A cerned with issues of larval mosquito ecology 1, A-G of Supplementto the Oxford English " and biocontrol, topics presently receivingun- Dictionary, 1972, that Thoreau had anticipated "ecology" precedentedattention, it seemstimely to bring him, using the spelling too, in a letter the implications of R. H. Whittaker's 5 king- dated January 1, 1858), those of us completing doms to the attention of all culicidologists. our higher education in the 1930-40swere both The crux of the matter is that while it is self- appreciativeofthe obviousgood sense ofmaking evident that all of us must refer to precisely the appropriate provision for the classification of sametaxa under such group-headingsas bacte- single-celledorganisms as a separatekingdom ria, algae and protozoa in ecologically oriented from the Animalia and Plantae, and puzzled by investigations,those concerninglarval nutrition the total neglect of the Protista in most of our for example, whole phyla which until a couple textbooks.And so,by the mid-1950s,H. F. Cope- of decadesago had been long-establishedwithin Iand was, as technological improvements were one of these 3 groups have lately been switched gathering momentum, proposing a 4-kingdom to another.A casein point is that of the "blue- arrangement of life forms that he had already green algae," the thousands of living speciesof been working on for 2 decades.From the rash which are now recognizedas the blue-greenbac- of alternative schemesthat followed, the 5-king- teria. This particular change has been overdue dom one unveiled in 1959 by R. H. Whittaker since Ernst Haeckel first argued for it almost stands out. This system was improved by its 125 years ago. Like many others, it has now author over the next decade;and in 1978,just 2 beenprecipitated by the new technolory ofbio- yearsbefore Whittaker's untimely death, he and chemistry and electron microscopy.AII of which L. Margulis presented a version that has since leavesthe uninitiated in much the same situa- been steadily gaining widespreadadoption. tion as fairground visitors wondering which Helpfully illustrated, a detailed account by eggcupthe coin will be under this time! Margulis and K. V. Schwartz,listing 91 phyla Before a simple demonstration of how chaos distributed among the 5 kingdoms, appearedin in the presentation of researchfindings relating 1982. It retained the name that Haeckel had to, e.9., Iarval mosquito nutrition must inevita- selectedfor anucleatedorganisms-the bacteria bly follow failure to faceup to the present reality and "blue-green algae"-within a major group of 5 kingdoms, a brief review of the recent ac- of his proposedkingdom Protista. This was Mo- cretion from 2 is in order. Those first 2. the nera [: single (-celled)],now elevatedto king- animal and vegetableones recognizedby the dom-status. The Fungi were likewise elevated, Greek fathers of zoologyand botany some2,300 and the kingdoms Animalia and Plantae of years ago,remained the basis for biological clas- courseretained. However,Haeckel's euphonious sification long after not a few current AMCA Protista was replaced by the name Protoctista members had completed their tertiary educa- (: "very first establishment") which J. Hogg tion. True, almost a century before Carolus Lin- had published some 5 years before the great naeus had developed our system of binomial German protagonist for Darwinism, assigningit "Proto- nomenclature, Antonie van Leeuwenhoek's to a fourth kingdom; embracing both homemade microscope was complicating mat- phyta ... and Protozoa"to reinforce the Ani- ters by beginning to raise the curtain on a whole malia, Plantae and a long-abandonedinanimate JounNel oF THEAvnnrceN Moseurro CourRor,AssocrATroN VoL.6,No.3 (Mineral) kingdom that had been proposed by 1988 (2nd ed, Margulis and Schwartz) Prokar- M. R. Beslerback in 1642. yotae Protoctista Fungi Animalia Plantae As a designation for primordial plants and animals published in 1860, only a year afber "The Charles Darwin's Origin of Species by Worse news is to follow. There is not only Means of Natural Selection,"the unhappily ugly internal disagreementabout the current number name of Protoctista clearly merits consideration of recognizablephyla (Margulis and Schwartz "almost for retention, despite the fact that its meaning plumped for 100 phyla" in the preface would be far more appropriate for the Monera. to their 1982 edition, actually listing 91, aug- Personally,I should like to associatemyself with mentedby a 92nd in 1988),but Barnes and his R. S. K. Barnesand J. O. Corliss,both of whom, collaborators(1984) allowed only "the equiva- in 1984,opted for the retentionofProtista. And lent of 70 phyla." really, the support of Margulis and Schwartz for Interestingly, too, Margulis and Schwartz Copeland's advocacy of Protoctista on the (both editions)and Sleighet al. (in Barnes,ed., grounds of its being absurd to call giant kelp by 1984)each Iist 27 phyla in the kingdom Protista "that a name (i.e.,protist) had come to imply (or Protoctista?)-but less than half of their unicellularity and thus, smallness" is rather phyletic names correspond! Those that do are slight. For Haeckel'schoice of a kingdom-name 10 with botanical terminations, the Chryso- "the meaning very first" for the microorganisms, phyta, Haptophyta, Euglenophyta, Crypto- surely had evolutionary rather than size impli- phyta, Xanthophyta, Eustigmatophyta, Bacil- cations. lariophyta, Phaeophyta,Rhodophyta and Chlo- "Five In the second,1988, edition ofthe King- rophyta, plus 2 protozoan ones, Ciliophora and doms . ." of Margulis and Schwartz (seelist of Apicomplexa. The 2 last-mentioned ones are "An recommended reading below), these authors similarly presented in Illustrated Guide to chose to replace Haeckel's other euphonious the Protozoa" published under the authority of name, Monera, by the harsh-sounding and em- the Society of Protozoologistsin 1985. "new inently forgettable name Prokaryotae That book lists some of the above "algal" (pro, before;karyon, seed,nucleus") solely be- groups as protozoa, the Chrysophyta as order "the causethis was introduced in new edition of Chrysomonadida, Haptophyta as order Prym- Bergey'sManual of SystematicBacteriol,ogy. ." nesiida,Euglenophyta as order Euglenida,Cryp- Apter though it may be, surely Monera's prece- tophyta as order Cryptomonadida,Xanthophyta denceby a century and a quarter should prevail, (in part) as order Heteromonadida, and Chlo- if only to honor Haeckel in the slow sequenceof rophyta (in part) as order Volvocida. These or- events that he initiated towards our new and ders are all placed within the class Phytomasti- "plant-like soundly based5 kingdoms. I must hasten to add gophorea(: flagellates") of subphy- that soundly basedthough these are, there is as lum Mastigophora- : by derivation, whip- "whips" always internal and external disagreement bearer, the having long been termed among the currently active taxonomists. This flagella (latterly, undulipodia). This subphylum makes it sufficiently confusing for us retired and 2 others,the Opalinataand the Sarcodina, generalists with time on our hands to keep comprisethe phylum Sarcomastigophora.A sec- abreast of relevant happenings.For super-spe- ond classof the Mastigophora, the Zoomastigo- "animal-like cialists, though, shutting one's mind to the phorea (: flagellates") includes whole thing seemsunderstandable enough in a such familiar genera as that containing the day when framing enticing grant proposals is sleepingsickness parasites, Trypanosorna-with increasinglytime-consuming, and indeedessen- which Margulis and Schwartz lump the Opali- tial to careerprospects. Hence this letter. nata in their phylum Zoomastigina, while an- Thus, the names of the kingdoms are (aside other of their phyla, Rhizopoda,embraces all from the oldest-establishedones, Animalia and amoebaeexcept those having axopodia, which Plantae, and the Fungi, of recent promotion- becometheir phylum Actinopoda. The latter of which more anon) in a state of flux. To cite and Rhizopodeaare superclassesof the phylum only 3 relevant books of the past decade,2 of Sarcodina, according to the Society of Proto- them by the same authors (referencesbelow), zoologists'recent guidebook.Such disharmonies the 1982-88 versions of the system read rather make it painfully clear why it took so long for like a reflection of some recently independent Haeckel's kingdom Protista to be adopted. Now nations vs. the Founding Fathers in the UN:- that it is up and running, surely a sensible step to keepthings moving along progressivelywould 1982 (1st ed, Margulis and Schwartz) Monera be to settle the issue of Protista versus