Thanks, Dean -- you've reminded me of something that hadn't
come up previously in the "Individual" discussion. Several times the
assertion has been made (perhaps even by me?) that an Individual is assumed to
be a single taxon. This assertion always triggered something int he depths
of my brain, but I couldn't figure out what -- but now I remember, the need to
deal with multi-taxon "lots" of organisms, and track them with sspecimen-like
(and hence Individual-like) properties. I believe Stan Blum dealt with
this extensively in the ASC data model (CollectionObject, I think it was
called), and it needed to accomodate not only multi-taxon lots of the sort that
you describe, but also things like fossil specimens that have multiple phyla, or
even Kingdoms, permanently combined within the same
"CollectionObject".
But this is only an asterisk, because it doesn't really break
the notion of "same taxon" for an Individual, as long as the scope of "taxon"
stretches all the way up to Domain. Even the sample with plants, animals,
and bacteria fall within the taxon circumscription of
"life".
But in any case, I agree with your general approach to
"derived" specimens/samples -- which happens a lot in the DNA tissue sampling
world. We can start with a multi-phylum aggregated lot, then split it out
not only to the individual organism, but all the way into the parts and tissue
samples realm.
I don't know how DwC handles this (ResourceRelationship
class?), but it's certainly important (and increasingly so) in the natural
history specimens realm.
Rich
Count me in as another late entry to this discussion, lurking under
the rumbling flight paths of the VLPs (Very Large Postings).
Here's a
potential case to consider in the whole "how to file all the parts" issues
that seem to be arising. It's a parent/child scheme that we're implementing
for our marine invertebrate specimen database. We think we are being
reasonable in the way we thought of this. We hope that this concept could be
accomodated by DwC. That's the sum of the contribution for consideration: we
hope DwC can/will cope with this. It may well be that it happily does so under
all of the "Individual" interpretations that are bouncing around. But hey, we
thought we'd toss it in just to make sure.
With marine invertebrates,
we very often find ourselves subsampling collected things (yes, "thing" is
deliberately vague to avoid misusing any heavy-baggage words). It is intrinsic
to the nature of the collections. Things often arrive as unsorted lots (think
of a jar full of coral rubble in 95% alcohol, sitting on our shelf). We want
to have a record for that jar in our database, so it gets one, with a
recordID.
Months later, we sort the jar to phylum level, and each of
those jars gets a record, each with a recordID, and those jars go on a shelf.
We treat those records as children of the unsorted-lot-record, and they each
have a pointer back to that unsorted-lot parent record.
Then we later
sort one of those phylum-level jars into species jars. Those, in turn, each
get a record with a recordID, and point to their parent phylum-level-jar
record. And so forth down to individuals in jars, and tissue samples of
individuals, and DNA extracts of those tissues.
To complete the
picture: many specimens do, of course, come in simply as an individual in a
jar. Those just get a record, and that's that: no parent, no child (no child
yet... until there's a tissue sample).
Key points:
1. We never know
how many levels of subsorting there will be. That differs from the
"preparation" orientation of many vertebrate collections (for example), where
there's a predefined set of preps that can come from each collected
individual. We very often don't start with individuals.
2. Each thing,
whether it comes in the door directly or is derived from something that did,
gets a first-class catalog record, and the sole unifying feature that gets us
the full information on a thing are the parent-child relationships of the data
records. Information has to continue to reside in those records and be
accessible from the "children" (an example would be a transfer to a different
preservative when pulling one individual into a specimen jar from a lot jar:
you need to know the preservative this thing is in now, and you also need to
know what preservative its parent thing was in).
3. One field of each
record has to document whether the item still exists: a thing may be
completely subdivided into subparts leaving nothing left over to put back on
the shelf. But in that case, we still keep the data record since it's still
the parent of the subsorted things and still holds the relevant historical
information.
So one day when we push these data out into the Wild World
in a DwC context, the thing we'd like to see accomodated is the ability of
systems outside our own walls to resolve back up that chain of subsorting to
build the whole information set for a thing, including the relevant
information from its logical "parents".
OK, now we'll be delighted to
hear that this scheme was obviously accomodated all along, or alternately,
that this whole concept is a pretty dumb way of cataloging our
holdings.
-Dean
--
Dean Pentcheff
Research
Associate, Natural History Museum of LA County
pentcheff@gmail.com
dpentche@nhm.org