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

Richard Pyle deepreef at bishopmuseum.org
Thu May 30 00:21:19 CEST 2013

Thanks, Ramona – this is an *extremely* helpful email! It helps clear things
up a lot in my mind.


Just to be clear, what I am looking for is the notion of a defined physical
object (what I think you mean by “material entity”), and I explicitly mean
the material entity itself.  Yes, there is information (properties) that
relate to that material entity, but to me that is a separate issue.  What I
would like to see clearly defined is the class representing the material
(physical) entity – which seems to me to be a superclass of what
materialSample is intended to represent.


Perhaps our (TDWG/DWC) community is not yet ready to deal with this level of
abstraction (unfortunately, I absolutely have to, because “Occurrence” is
simply way too overloaded a class for me to use independently of what I have
been calling “individual” and what I have been calling “Evidence”).  In that
case, I guess the best thing to do is accept materialSample as a
basisOfRecord for Occurrence and move on.  But this is more or less the same
thing that happened the last time we engaged in this conversation (2 years
or so ago), and I was hoping this conversation about materialSample could
leverage progress on the larger issue.


As I’ve said before, the last thing I want to do is confuse or otherwise
slow down the process of incorporating the term “materialSample” into DWC.
It’s just that I saw enough overlap with that “other” issue, that I was
hoping we could find a reasonable pathway forward on both.


Thanks again for the very helpful comments.





From: Ramona Walls [mailto:rlwalls2008 at gmail.com] 
Sent: Wednesday, May 29, 2013 9:14 AM
To: Richard Pyle
Cc: John Deck; Markus Döring; Steve Baskauf; TDWG Content Mailing List;
Robert Whitton
Subject: Re: [tdwg-content] New Darwin Core terms proposed relating to
material samples



I now understand more fully what you are asking for ( a clear definition
goes a long way!). A material sample, as we discussed it at the Kansas and
Oxford workshops, does indeed need to be physically removed from its
environment. This is also the case with the OBI term material sample, which,
as a subclass of OBI:specimen is the output of some collecting process. It
is true that concept of material sample could be defined to include sampling
in an observational sense, but that is not how it is defined at this point.
Based on this, material sample is NOT the term you are looking for or
defined as :

"The category of information pertaining to the physical basis of a sampling,
subsampling, or observational event. In biological collections, the
[SuperclassTerm] is typically a defined 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

What you have defined is a category of information (whatever that may be)
that pertains to some material entity. Not the material entity itself, but
information about that entity. The "SuperclassTerm" you refer to in the
definition sounds an awful lot like a material entity from the Basic Formal
Ontology, which is used for defining material sample in OBI and the
Bio-collections Ontology.



On Wed, May 29, 2013 at 11:51 AM, Richard Pyle <deepreef at bishopmuseum.org>

Many thanks, John.  This is extremely helpful!


First of all, in the context of a distinct term for basisOfRecord, I see
absolutely no problem with adding the term “MaterialSample”. I fully support
your proposal (although if this is simply a basisOfRecord term to be used
alongside Occurrence, PreservedSpecimen, LivingSpecimen, FossilSpecimen,
HumanObservation, MachineObservation; does it need a defined “ID” term? Do
all the others have defined “ID” terms?). 


However, I’m excited by this conversation because I think we are very close
to solving a bigger problem (which was the focus of the 2010 discussion on
this list around “IndividualOrganism”).


This bigger problem involves the need for a defined “concept” (I’m
hesitating to say “class”), and an associated “ID”, in dwc that refers to
the physical/material basis of an Occurrence.  We don’t yet have a term for
this concept in dwc (“IndividualID” hinted at the need for one, but that
term was not well-defined, and the term itself seems to cause confusion).
As Steve Baskauf and I have both been advocating for the establishment of
new class in dwc for exactly this purpose, I just want to make sure that
we’re on the same page about what each concept is.  The more I understand
about what you need for “materalSample”, the more convinced I am that both
of our needs can be met with the same concept.


I am perfectly happy to adopt the term “MaterialSample”, but I guess it all
boils down to this: In order for something to be a “MaterialSample”, must it
necessarily be removed from nature?   


If the answer is “No”, then I think we can merge the two concepts into one.


If the answer is “Yes”, then I think “materialSample” is best characterized
as a subclass of what Steve and I have been pushing for (setting aside, for
the moment, the additional complexity of taxonomically homogeneous vs.


In the latter case, I would define the superclass (whatever term is used for
it), along the lines of:


"The category of information pertaining to the physical basis of a sampling,
subsampling, or observational event. In biological collections, the
[SuperclassTerm] is typically a defined 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






From: jdeck88 at gmail.com [mailto:jdeck88 at gmail.com] On Behalf Of John Deck
Sent: Wednesday, May 29, 2013 4:01 AM
To: Richard Pyle
Cc: Markus Döring; Steve Baskauf; TDWG Content Mailing List; Robert Whitton;
Ramona Walls

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


Since the original proposal was from a group of folks, we decided to put our
heads together to construct a general response to the various issues and
ideas expressed on this thread. 


John Deck for Rob Guralnick, Ramona Walls, and John Wieczorek


In the text of the  issue submitted for MaterialSample (
https://code.google.com/p/darwincore/issues/detail?id=167) we noted cases
where the current basisOfRecord terms pertaining to the Occurrence class
(Occurrence, PreservedSpecimen, LivingSpecimen, FossilSpecimen,
HumanObservation, MachineObservation) do not adequately cover certain cases,
including: environmental sample (for metagenomic analysis), transcriptomes
(measuring genes but not taxa), and destructive samples (e.g. tissues
destructively sampled in order to generate genomic DNA).  The term we
borrowed from OBI (http://purl.obolibrary.org/obo/OBI_0000747) is broad
enough to be utilized across various cases that fulfill our criteria while
still maintaining a consistent, clear and human understandable meaning.  For
our purposes, we can think of “Material Sample” as any type of matter that
we can use in order derive further evidence needed for identifications, and
taxa, whether it is taxonomically homogenous, heterogenous, a single
individual, sets of individuals, or populations. 


How is MaterialSample different from Individual?  The intent of individualID
is fairly clear:  since an Occurrence represents an organism at a place and
time (per Markus’ email), the individualID term allows us to assign an
instance identifier for a particular organism that can be present in
multiple events. MaterialSampleID, on the other hand, is intended to allow
users to say that the basis of an occurence is a material entity (i.e.
matter) that has been sampled according to some particular method. Whether
or not this material entity is an individual (sensu individualID in DwC) is
an independent axis of classification. As was already pointed out, there is
no restriction on specifying that an occurence is associated with more than
one type, so any occurrence can have both an individualID and a


We maintain our position on the proposal for MaterialSample as a value for
the basisOfRecord, with an associated materialSampleID to identify instances
of them. Per Steve’s initial comments, we have already withdrawn the
proposal for a MaterialSample class distinct from that in the Darwin Core
type vocabulary, which should make it easier to evaluate the implications of
what we’re discussing.  




NOTES, MaterialSample from OBI:

OBI has fairly broad definitions of samples & specimens that are meant to be
utilized across many different scientific activities.  Material Sample is
defined as a “material entity that has the material sample role”, while a
material sample role is defined as “ a specimen role borne by a material
entity that is the output of a material sampling process”, and a material
sampling process is “a specimen gathering process with the objective to
obtain a specimen that is representative of the input material entity”.  





On Mon, May 27, 2013 at 11:59 PM, Richard Pyle <deepreef at bishopmuseum.org>

Hi Markus,

Great question!  Particularly because this is exactly the sort of use case
we designed our model around.

> if you take a tissue sample of the same tree every year, would the
> in individualID be the same for all of them or be different? WIth the
> dwc:individualID definition it would be the same for all samples. If I
> understand you correct each sample would have its own "individual"
> identifier in your proposal? It can't see how you can collapse these two
> into one definition.

No, that is not how we would handle it.

In our model, there would be one IndividualID to represent the tree,
spanning the time period beginning (more or less) when the seed was
germinated, until the time at which the entire physical structure of the
tree was disintegrated.  It is an individual tree.

There would be multiple Occurrence instances, for each time that someone
observed or sampled or otherwise wished to document some condition of that
tree. All of these Occurrence instances would refer to the same individualID
value (i.e., the "tree").  In the example above, this means there would be a
different Occurrence instance for each year that a sample is taken --
because in each case, an assertion that the full tree existed at a certain
time and place can be made (I understand that trees tend not to move around
very much, so the Location for each event associated with each Occurrence
would, in this case, remain the same; but the other Event properties -- such
as eventID, samplingProtocol, samplingEffort, eventDate, eventTime,
startDayOfYear, endDayOfYear, year, month, day, verbatimEventDate, habitat,
fieldNumber, fieldNotes, eventRemarks -- would be documented accordingly for
each sampling Occurrence instance).

Suppose that the tree is visited every month, but only sampled once per
year.  In that case, there would be an Occurrence record for every monthly
visit.  In other words, an Occurrence instance exists regardless of whether
a physical sample was made or not.  Any in-situ images made of the tree
would likewise be associated with the specific Occurrence instance, and each
image would represent a separate instance of "Evidence".

Now, let's focus on the annual samplings.  Every time a new sample is taken
from the tree, at least one new instance of Individual (with a unique
individualID value) is created to represent the sample.  This sample
(individual instance) may be a "gathering" (set of multiple individual
specimens gathered at the same time), or it may be a single specimen, or it
may be simply a tissue sample intended for destructive analysis.  In any
case, it's a new individual instance derived from the "parent" individual
instance representing the whole tree.  In our implementation, "Individual"
can be hierarchical, such that a whole-organism tree can be sub-sampled with
many "child" instances of "gatherings" (say, one gathering each year), and
each gathering may have multiple child "specimen" individuals (e.g.
individual botanical sheets created from the multiple items of a single
gathering), and each specimen may have further "child" subsamples extracted
for DNA analysis (or whatever), and the hierarchy can continue on down to
whatever derivatives that people feel a need to keep track of (e.g.,

The point is, all Individual instances are well-defined physical objects (or
well-defined sets of physical objects), and they can be arranged in a
n-tiered hierarchy.

Moreover, each Individual that can be characterized as a "sample" (what we
refer to as a "CollectionObject") may also have a property value for
"CollectionOccurrenceID" -- which refers to the specific Occurrence instance
at which the sample was obtained.

So, for example, if the tree is visited on May 27, 2013 and a specimen
(sample) is taken, then:
1) An Event instance is generated to represent the event where the tree was
2) An Occurrence instance is generated, which refers to the new EventID, and
the existing IndividualID for the whole tree, and includes whatever other
Occurrence properties are relevant for the tree at the time of this
3) An Individual instance is generated for the specimen, which has a
property value for parentIndividualID that refers to the individualID for
the whole tree, and a property value for collectionOccurrenceID that refers
the Occurrence instance where the specimen was collected.

So, to summarize the answer to your question:
- There are multiple Occurrence instances that refer to the same Individual
instance representing the whole tree (and, hence can be collapsed to the
same IndividualID value).
- Any Individual can have derivatives that are themselves unique Individual
- Individuals are arranged hierarchically, and certain properties can be
inherited up or down the hierarchy, depending on the properties and their
associated logical constraints.

At some point, I will assemble a set of other specific use cases, and how we
manage them through our use of the "Individual" instance (although I will
probably not use the word "Individual", as this seems to cause too much
confusion in these discussions).



John Deck
(541) 321-0689 <tel:%28541%29%20321-0689> 


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