Biogeographic memory

[John Grehan]

As far as I remember, with the introduction of cladistics only the term
"monophyly" changed  meaning (was clarified, as many would say). Most other
terms were new introductions.

Either way, there was debate about terminology.


Since the meaning of orientation is does not imply dispersal route the
suggestion that it does would arise only if one wants to treat orientation
that way. Hovenkamp raises some good suggestions for an expanded glossary
in the future.


As that is almost certainly not the way Mayr used the word "different", it
would seem that the entire discussion is based on semantical differences...

Perhaps, perhaps not. Either way, means of dispersal has failed to be a
general predictor of biogeographic pattern.

No? But compare fig. 3.11 b with fig. 1-10 b and c to see how a
distribution on both sides of the Pacific can be given a Pacific as well as
an Indian ocean baseline...

Designation of baselines does involve several considerations and it is
possible that because there is no spatiotemporally independent criteria the
procedure may be viewed as arbitrary. Where a distribution is adjacent to
more than one ocean basin it is not possible to use minimum distance alone.
In fig 1-10 b and c the distributions were spatially unproblematic.Two
other contributing elements are main massings and phylogenetic
relationships. This is discussed in some detail (maybe not enough for some)
for the ratites. Detailed assessment was not applied to the distributions
so one could argue that their Atlantic/Indian baselines is not sufficiently
supported in the text.

And to assign the same (Indian ocean) baseline to the tracks displayed in
fig. 3.3 b and 3.4 seems to me more than a little arbitrary.

The distribution of Pelargonium (3-3 b) is massed around the Indian Ocean
so an Atlantic or Pacific, or Southern basin could not be applied. The same
applies to the distributions in 3-4.

The comments by Hovenkamp do lead to some useful ideas about improvements
to the book in the future - particularly issues of clarification (always
difficult to anticipate). This kind of feedback was particularly difficult
to obtain in the past as most traditionalists wrote panbiogeography off so
one could not get constructive feedback. Panbiogeography is still banned
from some journals as a matter of editorial policy so even developing
debate over such issues can be quite restricted in venue. However,
Hovenkamp's comments show, however, that the most detailed critique of a
work may come from opposing research programs and so ironically 'opponents'
become ones best allies for improvement.

John Grehan