artificial units

[John Grehan]

Peter Stevens wrote

>To be somewhat bloody-minded, I would suggest that even units in
>panbiogeographic analysis are artificial.

The units are not referred to here, but if they are distribution localities
it is certainly true that there is an arbitrary element in determining the
level of resolution, but the localities themselves at the level of the
individual
organisms at least are not arbitrary. Either the organism is there or it is not.
I suppose that when dealing with a mobile organism is coordinates are
mobile also, but there can still be tracked (no pun intended).

Perhaps from a philosophical point of view anything "constructed" may
be considered artificial, but I was taking the generally accepted view that
a natural unit and natural classification did have some kind of direct
relationship to historical origin and events - such as groups sharing a common
origin in terms of most recent common ancestor are "natural". In this
sense I was looking to biogeographic units having a similar quality.

John Grehan