Systematic Botany (2006), 31(1): pp. 217–221
q Copyright 2006 by the American Society of Plant Taxonomists
Commentary
One-Dimensional Systematist: Perils in a Time of Steady Progress
JORGE V. CRISCI
Museo de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina ([email protected])
Communicating Editor: Gregory M. Plunkett
This commentary offers a critical assessment of the
molecular age of biological systematics and deals with
certain basic tendencies that seem to indicate a new
phase of the discipline. These tendencies have engendered a prevalent one-dimensional thought that undermines the very foundation of systematics. This new
phase has produced an advanced state of conformity
with its consequent stifling of criticism, restricting the
legitimization of problems and methods, research priorities, and last but not least, job opportunities and
modes of organization of institutions.
Biological systematics is a multidimensional scientific discipline that describes, names, classifies, and determines relationships among the Earth’s biota. It accomplishes these deeply interdependent tasks through
surveys, inventories, collections, description of species,
phylogenetic reconstruction, hierarchical classifications, monographing, and application of rules of nomenclature. All these activities, except phylogenetic reconstruction, are encompassed by the sub-discipline
named taxonomy (Wilson 2003).
Systematics provides a reference system for the
whole of biology and therefore can be seen as both the
most basic and the most wide-ranging area of biology.
It is the most basic because organisms cannot be discussed or treated in a scientific way until some classification has been achieved to recognize them and
give them names. It is the most wide-ranging because
it gathers together and summarizes everything that is
known about the characteristics of organisms, whether
geographical, morphological, physiological, genetic,
ecological, or molecular.
Beneath the fundamental scientific importance of
systematics for biology, lies a growing urgency. The
roughly 1.7 million species known to science to date
probably represent at best fewer than 15% of the actual
number. Of the named species, it is estimated that less
than 1% have been studied beyond the essentials of
geographic location, habitat preference, and diagnostic
morphology. At the same time, thousands of species
(known and unknown) are threatened by imminent extinction (Raven 2002).
Were we required to characterize the current age of
systematics by any single epithet, we should be tempted to call it ‘‘the molecular age.’’ Molecular data have
provided a new class of features that allow not only
phylogenetic reconstruction of closely related taxa, but
also broad scale comparisons across all organisms
from bacteria to mammals and plants. Unquestionably,
we are witnessing an extraordinary time when molecular systematics is generating an unprecedented revolution within the discipline (Daly et al. 2001).
Despite the tremendous advances, there are profound perils in the molecular age of systematics: 1. An
unbalanced emphasis favoring phylogenetic reconstruction based on molecular data at the expense of
taxonomy; 2. A narrow research program that ignores
many aspects of organismal biology and fragments
systematics; 3. An unbalanced education of the new
generation of systematists; 4. A depreciation of natural
science collections as part of a broader trend away
from organismal biology; 5. A slowdown of taxonomic
work that will affect the conservation of biodiversity;
and 6. An intellectual climate that marginalizes those
with different views. I will briefly elaborate on these
perils and their consequences.
An Unbalanced Emphasis. Taxonomy was once the
proud flagship of the natural sciences. Charles Darwin,
the founder of the theory of natural selection, working
in Cirripedia (barnacles) in the 19th century and Willi
Hennig, the founder of modern phylogenetic reconstruction, working in Diptera (flies) in the 20th century,
were both practicing taxonomists. However, in the last
30 years taxonomy has seen a gradual loss of credibility among fellow scientists. This image problem is
based on misconceptions of how taxonomy works. The
view that taxonomy is a purely descriptive branch of
knowledge that consists only of observations (Anonymous 2004) is a clear example of these misconceptions.
In fact, taxonomy is a scientific discipline that requires
description, but also theoretical, empirical and epistemological rigor, a hypothesis-driven approach, and
field and lab expertise (Stuessy 1990; Carvalho et al.
2005).
Furthermore, classification systems are hypotheses.
A taxon, the basic unit of taxonomy, is a classification
system and as such is a scientific hypothesis about order in nature (Thiele and Yeates 2002). Like every scientific hypothesis, a taxon goes beyond the evidence
(observations) for which it purports to account. That
is, a taxon has greater scientific content (e.g., predictive
capability and explanatory power) than the empirical
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propositions it covers. This taxon-hypothesis, once its
scientific content is tested and corroborated, permits
scientists to study aspects of biology other than systematics (ecology, biogeography, comparative physiology, comparative morphology, genetics, conservation,
etc.).
Simultaneous with the image problem of taxonomy
and linked to it, there has been an overwhelming focus
on molecular-based phylogenies among funding agencies, research institutes, universities, and journals that
publish high-profile systematic research, which has led
to tremendous advances. However, these advances
have come at a cost: a lack of interest (funding, job
opportunities, and publication venues) in the general
area of taxonomy (Kruckeberg 1997; Lammers 1999;
Wilson 2000; Landrum 2001; Wortley et al. 2002; Scotland et al. 2003; Wheeler 2004).
Reliance on the Science Citation Index (SCI, or Impact Factor) as a measure of ‘‘good science’’ contributes
to this unbalanced drive (Valdecasas et al. 2000), since
fewer and fewer journals are available to taxonomists
for publishing their work. Compounding the problem,
the SCI draws its statistics from the number of authors
citing a paper during a short period of time (ten years),
whereas a taxonomic work usually has few citations in
the first ten years but lasts longer in the ‘‘citation
world’’ (i.e., has a longer ‘‘citation half-life’’) than any
molecular paper.
A Narrow Research Program. Systematics is faced
with several superimposed levels of integration of
structures and functions, including molecules, organisms, populations, and species.
The dominant discourse in the discipline has a
strong emphasis on the molecular level at the expense
of the organismal level. Evidence of this narrow research program includes recent attempts toward the
molecularization of taxonomy (DNA barcoding) using
a few chosen (‘‘standard gene’’) sequences across all
organisms to discover, characterize, and distinguish
species, and to assign unidentified individuals to species (Tautz et al. 2003). On the other hand, this molecularization of taxonomy appears inadvisable for both
practical and theoretical reasons (Dunn 2003; Lipscomb et al. 2003; Seberg et al. 2003; Lee 2004; Will
and Rubinoff 2004).
Most of the information about organisms (morphological, anatomical, physiological, cytological, ecological, etc.), which is of interest and of use for understanding their nature and evolution, is of course, in
some way determined from information at the molecular level; however, it is unrecoverable from data at
this level. Such emergent properties must be studied
directly, and an extreme emphasis on the molecular
level leaves little or no time and effort for the search
for new properties at the organismal level.
Importantly, although in microbial organisms it is
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possible to get information about organismal diversity
and phylogeny using only molecular data (e.g., DeLong and Pace 2001), in general, molecular systematics
requires a taxonomic framework with information at
the organismal level in order to be more generally useful.
Lastly, a consequence of a narrow research program
is a fragmentary approach to nature. Fragmentation in
science arises when an attempt is made to impose divisions in an area of knowledge in an arbitrary fashion, without regard to a wider context (Bohm and Peat
2000). An analogy from human vision will help us to
see the perils of a fragmentary approach in science.
The details of what we see are picked up in a small
central part of the retina called the fovea. If this is
destroyed, then detailed vision is lost, but general vision, which comes from the periphery of the retina,
remains. But if the periphery is damaged, while the
fovea remains intact, even the details lose all their
meaning. By analogy, systematics is in danger of suffering a similar ‘‘damage’’ to its vision. By giving so
much emphasis to molecular data, systematics is losing
sight of the indispensable wider context of its field of
study.
An Unbalanced Education. In 1970, two systematist-statisticians, Robert R. Sokal and F. James Rohlf,
published a paper entitled, ‘‘The intelligent ignoramus’’
(Sokal and Rohlf 1970). They discussed the establishment of relationships among organisms (5 ‘‘phylogenetic reconstruction’’ in modern terms). They asked:
Are the differences between different hypotheses of relationships due more to the difficulty of choosing appropriate characters, or to processing extensive and
complex information? If the former is true, there is a
good reason to value deep experience in a particular
group of organisms. If the difficulties are mainly those
of processing complex information, an inexperienced
worker should be able to choose characters that give a
satisfactory hypothesis. They described a worker ignorant of the particular taxon to be studied but trained
in the techniques of collecting characters and analyzing them with numerical computational methods. After a series of experiments Sokal and Rohlf predicted
a future where technicians, untrained in taxonomy,
could generate acceptable hypotheses of relationships
through automation of the data-gathering process and
a numerical computational analysis of the data. It
seems that Sokal and Rohlf’s ‘‘future’’ is the current
curriculum of most universities, since the new generation of systematists is strongly specialized on gathering molecular data and analyzing them with the use
of computer algorithms, with little instruction in taxonomic work, such as collections, identification, description of species, construction of keys, delimitation
of gross and ultrastructural morphological characters,
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CRISCI: ONE-DIMENSIONAL SYSTEMATIST
chromosomal work, nomenclature, etc. (Sytsma and Pires 2001).
From time to time, systematics (as with any other
scientific discipline) needs a labor of reconstitution as
a necessary contribution to its own advance. This demands an effort towards unification involving broad
areas of biological knowledge, areas that lie outside the
extreme specialization of an intelligent ignoramus. The
late Lawrie Johnson, an outstanding Australian systematist, wrote in 1968 (Johnson 1968) ‘‘If systematics
is made into a sterile exercise, a purely pragmatic service, or a playground for technicians, I would advise
intelligent young biologists to steer well clear of it.’’
A Depreciation of Natural Science Collections.
Specimens in natural science collections are preserved
to document the presence of organisms in given localities at a given time, to validate past research, and to
be available for future research. Specimens also represent a sample of a region’s natural and cultural environment; preserving them is to preserve humanity’s
environmental heritage. The plight of a growing number of natural science collections has received some attention in scientific journals (e.g., Dalton 2003). Cutbacks are attributed largely to poor state budgets, but
some biologists (Gropp 2004) believe the problem is
due to a bias of some university and museum administrators towards molecular biology.
On the other hand, it is clear that a broader trend
away from organismal biology will include, inevitably,
a depreciation of natural science collections. For instance, the recent characterization by some editors of
voucher information (the specimens examined in a
study) as ‘‘supplementary material’’ and the fact that
many phylogenies based on molecular data have been
published without any information on specimens examined, are probably a side effect of the molecular age.
This indifference to vouchers by some editors and
some researchers is a step back in systematics, since
repeatability is the cornerstone of the scientific method
and vouchers are the basis of the reproducibility of
results (Ruedas et al. 2000; Funk et al. 2005; Kristiansen et al. 2005).
A Slowdown of Taxonomic Work. Through the
Convention on Biological Diversity, governments have
acknowledged the existence of a ‘‘taxonomic impediment’’ to the sound management of biodiversity. This
‘‘taxonomic impediment’’ results from the knowledge
gaps in our taxonomic system, the shortage of trained
taxonomists and curators, and the impact these deficiencies have on our ability to conserve, use, and share
the benefits of our biological diversity. The Global Taxonomy Initiative (GTI) is a program that has been established by the Conference of the Parties of the Convention on Biological Diversity to reduce the taxonomic impediment, and thereby to improve decision-mak-
219
ing in conservation, sustainable use, and equitable
sharing of the benefits derived from biodiversity.
A recent report by the House of Lords of the United
Kingdom (2002) pointed out that the science of systematic biology is a vital discipline that underpins the conservation of the Earth’s biodiversity and recommended
to its government strong support of taxonomic work
and major fundings to natural history collections.
Working in the same direction are programs such as
the United States National Science Foundation’s PEET:
Partnerships for Enhancing Expertise in Taxonomy
(Rodman and Cody 2003). The GTI, the House of
Lords’ report, and the PEET program explicitly recognize the societal value of taxonomy and the need of
good taxonomy for the conservation of biodiversity.
An Intellectual Climate. Systematics, as with any
other human activity, has a social context. Peer pressure plays a significant role in shaping the spirit of the
age. Social scientists have studied how the climate of
opinion depends on who speaks and who keeps quiet,
and describe the process as a ‘‘spiral of silence’’ (Noelle-Neumann 1993). Observations made in one context
spread to another and encourage people either to proclaim their views or to suppress them and keep quiet
until, in a spiraling process, one view dominates the
public scene and the others disappears from public
awareness and their adherents become mute.
This social phenomenon is what Alexis de Tocqueville (1856) described when he wrote in his history of
the French revolution: ‘‘. . . dreading isolation more
than error, they professed to share the sentiments of
the majority . . . So what was in reality the opinion of
only a part . . . of a nation came to be regarded as the
will of all and for this reason seemed irresistible, even
to those who had given it this false appearance.’’
In this sense, a peculiar dynamic has developed in
the molecular age of systematics. Those who are convinced that molecular data are going to be adopted by
everyone express themselves openly, and self-confidently defend their views. Those who are against the
unbalanced emphasis on molecular data (though most
definitely not against its use for phylogenetic reconstruction and other appropriate areas) feel themselves
left out; they withdraw and fall silent. That most of
those who are unhappy with the current narrowness
of focus of the field have been cowed into silence, reinforces the false impression that the current view has
stronger intellectual and political support than it indeed has.
Editors, peers, administrators, and policy-makers
(though fortunately not all of them) become enforcers
of a vox populi-vox dei in systematics. This trend is leading the systematics community to historical amnesia
(Nelson 2004) and to a new kind of superficiality (in
the most literal sense) where technological advance is
equated with conceptual progress (Heads 2005).
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Conclusion. The value of molecular data in systematics is undeniable. However, there are profound
perils in a strict dominance of its view over the rest
of the tasks of systematics. The current atmosphere
within the discipline is fostering a trend to what political scientists call ‘‘incestuous amplifications’’
(Krugman 2003), a condition where the decisionmakers listen only to those who are already in lockstep agreement with them, reinforcing a set of beliefs
and creating a situation ripe for misjudgments. An
unbalanced systematics and its aftermath (a narrow
research program, one-dimensional education, and
depreciation of natural sciences collections) are serious misjudgments in a time of biological extinctions.
Systematics is a basic tool in the conservation of biodiversity, and it is only by moving beyond the present
fragmentation that the discipline can hope to make a
realistic contribution to ameliorate one of the most
serious problems facing humanity. On the other
hand, it would be dreadful if molecular systematics
ended up by swallowing its parent. To prevent this
catastrophe from occurring, it will be necessary to
realign priorities following a systematics agenda that
will ensure a harmonious progress of the discipline.
We are in a time when systematists, particularly taxonomists, are increasingly and distressingly accustomed to hearing themselves defined pejoratively. I
write, therefore, as someone who notes his own convictions regarding what systematics is as a whole: a rigorous multidimensional scientific discipline.
ACKNOWLEDGEMENTS. I thank Michael Heads, Thomas Lammers, Federico Ocampo, Guillermo Orti, Paula Posadas, Marilyn
Smith, David Spooner, and especially Liliana Katinas and Robert
Kowal for the critical reading of the manuscript. In addition, I
gratefully acknowledge my reviewers Richard Olmstead, Vicki
Funk, and two anonymous ones, even when they may not have
agreed with my views. Lastly, I appreciate the editors of Systematic
Botany, especially Patrick Herenden and Gregory Plunkett, for improving my manuscript and allowing me to publish it and, in
general, for publishing articles covering the full gamut of modern
systematics.
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