[tdwg-content] New Darwin Core terms proposed relating to material samples

Richard Pyle deepreef at bishopmuseum.org
Mon May 27 23:16:20 CEST 2013

Hi Markus,

Very briefly:

> First of all I see an essential difference in character between the
current dwc
> idea of Individual(ID) and a MaterialSample, Occurrence, Evidence or

Yes -- everyone seems to agree that Occurrence, Evidence, and Individual are
fundamentally different things (as are Event, Location, Taxon, etc.).

The part that is not so clear to me is where the difference is between what
was intended to be represented by dwc:individualID, and what is proposed for
materialSample(ID).  There seems to be some broad overlap in these two
things, with no clear distinction of where one ends and the other begins.

> The Individual has no notion of time and space, whereas the others all

I don't think it is true that MaterialSample has a notion of space and time
-- any more so than individualID does (or should).

The proposed definition of materialSample is:

"The category of information pertaining to the physical results of a
sampling (or subsampling) event. In biological collections, the material
sample is typically collected, and either preserved or destructively

There is no class "individual" in DWC; but if there were one, it should have
a definition something like this:

"The category of information pertaining to the physical basis of a sampling,
subsampling, or observational event. In biological collections, the
individual is typically a named group of organisms, a single whole organism,
or a part of a whole organism that is collected or otherwise documented in
nature, and either preserved, destructively processed, or documented through
some form of Evidence (such as images or reported visual observations)."

At least, that's how we have interpreted the generalized intended meaning of
what an "individualID" should refer to (i.e., identify).  Unfortunately, as
has already been pointed out repeatedly in this thread, the term
"individual" comes with a lot of baggage, and is not the best term to use
(for several reasons). Also, the current definition of dwc:individualID is
very thin and too narrowly focused on "resampling" -- which is certainly one
of the reasons for having such a class, but also certainly not the only

> IndividualID was primarily added to Darwin Core to group occurrence
> about the same "Individual", e.g. when dealing with bird ringing, whale
> tracking or tree tagging. It could also provide useful to track herbarium
> duplicates. The actual Individual class does not hold any direct dwc term
> they are all dependent on time or locality (think about occurrence
> such as life stage, sex, behavior etc). So in this light MaterialSample
> Individual are very different concepts which we should keep distinct I
> believe.

I don't agree.  Our own interpretation of what an individual class would
look like was very-much shaped by the earlier (2010) discussions on this
list for what was actually needed by more than a few data providers and
consumers.  While the addition of "dwc:individualID" may have been done
hastily and with a narrow purpose in mind, the broader problem is that the
"Occurrence" class is overloaded.  I agree with you that the properties that
you mention (life stage, sex, behavior, etc.) are properly a function of
time and space, and therefore are legitimately associated with a specific
Occurrence instance; however, certain other terms associated with
dwc:Occurrence (such as catalogNumber, preparations, disposition,
otherCatalogNumbers, previousIdentifications, associatedSequences, and
taxonomic determinations) are independent of time and space, and are
inherently properties of the "individual"/"materialSample" instance.

Put another way, the reasons why an instance of "materialSample" is not
equivalent to an instance of "Occurrence", are the same reasons why the
notion of "Individual" (sensu me) and "IndivisualOrganism" (sensu DSW) are
not equivalent to an instance of "Occurrence".

The motivation for my initial posting to this thread was the recognition
that many of the reasons for establishing "materialSample" are the same as
the reasons why Steve Baskauf, and I, and a number of others saw a need for
"IndividualOrganism" (or whatever it should be called). This is not to say
that they necessarily *are* the same thing (materialSample and
IndividualOrganism) -- but the overlap is broad enough that it bears some
deserves some discussion -- if for no other reason than to inform the
discussion on "materialSample" by what has already been discussed for
"IndividualOrganism"'; and to clarify the definitions of each to make sure
the community (both providers and consumers) understand the differences
between them.

> Another surprising outcome of an exercise to actually map a large number
> use cases to darwin core records with real values (using the text
> was that we ended up preferring a dynamically typed Occurrence class via
> the basisOfRecord property and mostly did away with any class terms. This
> actually draws on Steves proposal to only add a new dwc type term to
> basisOfRecord instead of creating a new MaterialSample class term. Along
> with a much richer, hierarchical and probably ontology controlled
> of such basisOfRecord terms we felt we can go a long, long way.

This is very similar to our thinking on this as well; except we have found
reasonably good congruence between many key properties with the specific
basisOfRecord, such that some of them (particularly Evidence and
IndividualOrganism) emerge in a way that seem to justify recognition at the
Class level.  In any case, we need to be careful not to overload
"Occurrence" even further.  I think that, whatever we do, we should focus on
reducing confusion, rather than increasing it.


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