BIOLOGICAL NOMENCLATURE, CLASSIFICATION AND THE

Transcription

BIOLOGICAL NOMENCLATURE, CLASSIFICATION AND THE
BIO LO G IC A L NO M EN CLA TU RE, C LASSIFICATIO N
AND THE ETHNOZOOLOGICAL SPECIEM E
M ichael J. Tyler
U niversity o f A delaide
INTRODUCTION
The objectives o f biological nomenclature on the one hand, and constructing and maintaining a hierarchial
system of classification on the other, are related but distinct. In his classic work Systerna N aturae , Linnaeus
(1766) adopted a binomial nomenclature, whereby each animal was given a specific and a generic name.
Although zoologists now use a modem language for the description of the taxon, Latinisation o f specific and
generic names (as used by Linnaeus) is adopted universally.
To promote universality and aid stability of nomenclature, various regulatory codes have been proposed
throughout the past century. There is now a single code (The International Code o f Zoological Nomenclature ,
Third Edition, adopted by the 20th General Assembly of the International Union of Biological Sciences, and
published in February 1985). That Code, like its predecessors, addresses problems such as those of
homonymy and synonymy, and provides the procedural mechanics for resolving them.
Nomenclature is a utilitarian device: we must communicate. To the uninitiated it is perhaps a surprise to
discover that the practice o f zoological nomenclature is volatile and generates more heat than a nuclear reactor.
Classification in biology creates a hierarchical system of units of decreasing magnitude ranging from the
Animal Kingdom as a whole through to a recognisable component o f a portion of a single species. Linnaeus
used what would today be considered a simplistic scheme involving only five units within the Kingdom:
Class, Order, Genus, species and variety. Subsequently the number of units increased as the need for them
arose and the complexity and diversity of the Kingdom was revealed. It is apparent that there is considerable
divergence o f use o f classification, such that zoologists working on fishes and reptiles may have totally
different perceptions of a Family unit. Similarly at a level below a genus there is no uniformity in the
nomenclature o f “sub-generic” units.
The problems of classification have been compounded over the past 25 years by the introduction of
biological and molecular techniques demonstrating that biological and genetic divergence is not always
accompanied by morphological change. Thus they may demonstrate that two genetically distinct populations
meriting recognition at a species level may be identical in their appearance.
Clearly the hierarchial classification has proved inadequate to accommodate the subtleties of various degrees
of divergence between and within populations, and also inadequate to express various degrees of affinity
between species within a genus. This comment is equally valid in anthropology in the study o f communities
and their history, and their assumed origins and relationships.
Here I address some o f the problems that exist. I have in part been deliberately provocative, in the hope
that the contribution will generate meaningful discussion. It is against that background that I put in perspective
the implications of one o f Ralph Bulmer’s findings in ethnozoological nomenclature.
CLAS SIRC ATION HIERARCHY
Mayr (1969) summarised the “generally accepted categories” in zoological classification as follows:
Kingdom
Phylum
Subphylum
Superclass
Class
Subclass
Cohort
Superorder
Order
Suborder
Superfamily
Family
Subfamily
Tribe
Genus
Subgenus
Species
Subspecies
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The Ethnozoological Specieme
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Mayr also drew attention to a number o f supplementary subdivisions between Class and Superfamily.
Twenty years on, it is clear that a vast number of additional categories has become in vogue or has been coined
to accommodate varying degrees of divergence and affinity, particularly below the level of genus. The point
has been reached where the practice o f classification amongst contributors between and even within different
Classes, has become blurred.
CLASSIFICATION UNITS BELOW THE GENUS
Within the last decade I have encountered the following terms being employed by those engaged in studies
of organisms below the level o f genus. I have chosen to present them in alphabetical order to eliminate any
suggestion of a hierarchial inference:
chromosomal race
clone
cryptic species
cytotype
dilectal races
ecospecies
forma
incipient species
infra-genus
klepton
morph
morpho-species
morphotype
polymorph
race
sibling species
species aggregate
species assemblage
species clade
species complex
species group
species taxon
sub-genus
sub-species
super-species
synklepton
variant
variety
At its most generous interpretation it could be argued that contributors probably are grappling with a need
to give expression to meaningful aggregations of species, or genetic or other attributes within and between
interbreeding individuals forming populations. The unit o f choice (independent o f the name given to it) will
reflect intent. Some terms probably are synonymous but, given the rarity with which the use o f a unit in a
publication is defined by the author, it is difficult to recognise synonymy and ambiguity when they occur.
Nevertheless it is highly significant to observe that nomenclatural options below the genus exceed those from
Kingdom to genus.
DIVERGENCE AND HIERARCHY IN CLASSIFICATION
Compared with the approaches to systematics o f perhaps 20 years ago, it is likely that the multiplicity of
nomenclature below the level of genus is attributable to
(a) the independence of workers employing different scientific techniques to address problems, and
(b) the varying degrees of divergence in the taxa examined.
At a broad brush level it is evident that the proportion of units observed differs between workers studying
organisms in different classes. For example ornithologists do not seem to use units between genus and
species. The obvious explanation is they do not recognise genera containing many species, and in fact
monotypic genera are extremely common: units between genus and species do not seem to have much use
amongst ornithologists.
The above observation raises the obvious question as to just why speciose genera do not exist amongst
birds. Is it the existence o f limited intra-specific variation? (Certainly morphological variability will
contribute, because the less discrete a population, the greater the likelihood o f a ‘splitter’ taxonomist creating
discrete taxonomic units.)
But if those studying different Classes produce different concepts o f genera, does it matter very much? I
would suggest, tentatively perhaps, that comparative studies o f evolution as a whole (across vertebrates)
would only lead to confusion if the genus is perceived as being as natural a unit as a species. I suspect that
above the species, collective terms are utilitarian. It is only when we try to create an orderly hierarchy that
problems are likely to be created.
Concerning the second point, namely whether different degrees o f divergence in the taxa being studied
contribute to nomenclatural problems, Figure 1 represents the difference in age since origin of eight congeners.
Nothing is inferred about their phylogeny - only that they have existed as discrete genetic units for varying
periods. There is nothing particularly profound about it - only that in examining discrete populations at a
single fixed point in time, their varying histories and age will no doubt influence their degree of difference
from one another, whether the viewpoint is gross morphology, the chromosome or whatever.
166
Michael J. Tyler
Congeners
Figure 1: Variation in times since origin amongst eight members of a genus. Comparison at
the fixed point in time (1988) must accept the difficulty of according each an identical status
It would seem that the ability to recognise, in theory and practice, that age and divergence differ, cannot be
accommodated adequately below the genus, above the species or within the species. The process of speciation
and attainment of genetic integrity is so dynamic that populations, as well as perceptions of them, differ. Any
attempt to impose a hierarchial structure upon the multiplicity of nomenclatural units would be doomed to
failure.
THE SPECIEME CONCEPT
Ralph Bulmer’s initial studies on the vertebrate fauna known to the Karam led to a comparison of the
perceptions of kinds, the criteria for their recognition, and the hierarchical system within which units were
arranged.
Examining the manner in which Lêvi-Strauss was justified in applying the category “species” for categories
in ethnozoology, Bulmer (1970:1089) observed
It seems to me important that a species is not merely to be definable by multiple criteria, but that these
criteria are almost infinitely extendible in number. Having isolated a valid natural species (in the
biological as well as in the logical sense), the more closely one examines it, the longer the list of
characters one can note which contrast it with other species.
It is quite plain that the species is here viewed from the aspect of its distinctiveness from others. Bulmer is
emphasising the number and extent of the characters that are unique to the species. With this attitude in mind
there developed the concept of a “specieme” in which “natural kinds” recognised in a folk-taxonomy need not
necessarily equate with a species (Bulmer and Tyler 1968). Certainly it was noted that many speciemes did
correspond to species but others did not. The explanation for the non-correspondence was not scientific
inaccuracy, but rather a different perception of what kinds were all about, and the utilitarian objective of the
nomenclature employed.
MUTUAL PROBLEMS
My purpose in drawing attention to the specieme concept is to suggest that there may be parallels between it
and the evident scientific nomenclatural problems that exist directly above and below the level of a species.
The biological species concept requires potentially interbreeding individuals producing viable and fertile
offspring retaining that capacity. But when does a species become a species? It is easy enough to enumerate
criteria such as the acquisition of pre-mating and post-mating isolating mechanisms and genetic integrity, but
The Ethnozoological Specieme
167
the absolute moment in time cannot be determined with any degree of accuracy. But the evolutionary
milestone of a segment of a population becoming a new species is not necessarily accompanied by a fanfare of
morphological trumpets. It is where gross morphological diversity is slight that nomenclatural problems arise:
different workers may use different techniques and their perceptions of the status of elements of a natural kind
may also differ.
Darwin (1874) commented on the difficulty of accommodating racial differences in nomenclature of a
species, and stated, “The choice of terms is only so far important in that it is desirable to use, as far as
possible, the same terms f o r the same degrees o f difference [italics mine]”.
There are few modem workers who would agree with adopting such a principle, for it would seem that the
degree of difference varies between units that in an evolutionary sense merit being accorded a similar status.
Our concepts of what is important and significant have not just changed, but have been supplemented by the
ability to explore similarity and diversity using techniques that formerly were unknown.
It is impossible to arrange all of the nomenclatural units, above, in a hierarchial, two dimensional structure.
Several schemes involving different parameters of measurement and different dimensions are included. The
data have been obtained independently.
I
am not suggesting that the species is not a natural entity, only that components of the phenotype and
genotype are perceived in different ways, and that the species concept is becoming blurred. We are trying to
squeeze a dynamic 20th century concept into a static 18th century mould. The latter is not big enough and is
the wrong shape to accommodate it: the result is a lot of little odd fragments of the species floating around
trying to find a home.
Perhaps it is my perception that is wrong, and in reality the species concept is indeed becoming more
malleable, to accommodate change. But, malleable or rigid, the broader specieme has something to offer and
the future debate on species, kinds, speciemes and nomenclature is one that R.N.H.B. would approve.
REFERENCES
BULMER, R.N.H., 1970. Which Came First, the Chicken or the Egg-head? in J. Pouillon and P. Maranda (eds),
tchanges et communications: Melanges offerts a Claude Lêvi-Strauss a I’occasion de son 60eme anniversaire.
The Hague, Mouton. pp. 1069-91.
----------- , and M.J. TYLER, 1968. Karam Classification of Frogs. Journal o f the Polynesian Society, 77:333-85.
DARWIN, Charles, 1874. The Descent of Man, and Selection in Relation to Sex. 2nd Edition, 1883. London, John
Murray.
LINNAEUS, Carolus, 1766. Systema Naturae. 12th Edition, London.
MAYR, Ernst, 1969. Principles of Systematic Zoology. New York, McGraw-Hill.
ETHNO-ICHTHYOLOGY IN THE UPPER WAINIMALA VALLEY, VITI LEVU
Alanieta Waqaniu and Garth Rogers
University of Auckland
Fiji embraces over 320 islands and many Fijians1 live within the sound of the sea and extensively exploit
the marine environment. But people of the interior of Viti Levu, the largest island2 in Fiji,3 may live up to 50
kilometres from the coast and are therefore denied direct access to marine resources.4 Instead, they extensively
forage the forests and bush and the rivers, streams and swamps which abound in the region. For the
mountainous interior of Viti Levu raises to over 100 metres in several areas and is dissected and worn by
several long rivers and their extensive tributaries. These rivers are the focus of economic life for numerous
peoples of the interior,5 and often their best means of communication with one another and the outside world,
providing easy access by means of rafts and punts to much of their garden land,6 and supplying a reliable
source of protein in the form of fresh- water fish, eels, crabs and prawns. This essay examines the
classification of these fresh-water resources at Nawaisomo on the Waicakena River, a tributary of the upper
Wainimala River.7 We note how some of these creatures articulate with van u a and m a ta q a li social
classifications and are used to portray some kinship relations.

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