Role of Systematics

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This is in response to the question raised - what is the place or 
ranking of systematics in paleontology?

The way I see it there are two ways of looking at this.  The 
first it to view systematics as a means of understanding 
phylogenetic relationships among organisms, establishing 
evolutionary pathways and reconstructing the course of evolution 
through time.  As an end in itself, I would say that this aspect of 
systematics would rank equally in value with other branches of 
paleontology, such as paleoecology, biostratigraphy, etc.  Clearly, 
understanding the history of life on earth is one of our primary 
goals.

The second aspect is that systematics is the means by which we 
define taxa, establish criteria by which we can indentify particular 
taxa and the methodological approach we use do this.  
Identifications of particular taxa at particular points in time 
and space are the primary bits of data for most paleontological 
applications such as biostratigraphy, paleobiogeography, etc.  It 
stands to reason, therefore, that identification of taxa is the 
single most important part of paleontological data aquisition.  
Misidentifications and identifications of poorly defined taxa are 
bad data in the same way as an incorrect radiometric date or 
geochemical analysis.  Systematics is the "instrumation" by which 
we aquire taxonomic identifications and is therefore fundamental 
to any paleontologic application that uses occurrences of taxa as 
the data points.

As an example of how systematic approach can affect the outcome 
of a paleontological study, I was involved, a number of years 
ago (and continue to be involved in) occurrences of graptolites 
across the Late Ordovician extinction event.  Using the 
traditional means of defining diplograptid genera on the basis of 
thecal form, some seven or eight genera were known to span this 
boundary.  Employing different criteria to define genera 
(astogenetic growth patterns + thecal form) combined with a 
phylogenetic systematic approach, it became apparent that only 
one or two genera span this boundary and many others become 
extinct.  In addition, the newly defined are much more 
biostratigraphically restricted than the "old" ones (hence, more 
useful).  In this case, a change in systematic approach resulted 
not only in (hopefully) better taxonomic definitions (ie. better 
data), but also in a completely new view of one of the major events 
in the history of life.  

We cannot abandon the pursuit of systematics, either in 
terms of improvement in methodology or in its practice in 
particular taxonomic groups, any more than chemists can give up 
on developing, improving, maintaining and using their analytical 
instruments. 

Mike Melchin, Chair
Geology Dept., St. F.X. University
P.O. Box 5000, Antigonish, N.S., Can
B2G 2W5  902-867-5177, FAX - 902-867-5153
mmelchin@juliet.stfx.ca