Re: Fossil Record 2 database

[NEIL CLARK <NCLARK@xxxxxxxxxxxxxxxx>]

Barry wrote:-
> In a classification, two families would represent two
> mutually exclusive groups of genera.  But in a phylogenetic 
analysis, one
> "family" of canonical systematics may turn out to be a subset of 
another
> "family."  Is it all right for both "families" to carry equal weight in an
> analysis like Benton's?

I'm sorry I haven't been able to read Benton's analysis, but I have no 
problem with the _possibility_ of canonical families carrying equal 
weight despite being a subset of another in a phylogenetic analysis.  
On the other hand, I don't think we can state that 'Families' are equal 
in any sense except according to our own subjective interpretations 
in standardising classifications of any kind.  What I was saying in my 
previous post was that because we don't have a bottom-line definition 
for what a Family is - except a group of closely related genera- we 
can't compare a plant Family with an animal Family, or even an 
animal Family with another, but this is no reason for not recognising 
that there are characters that bind the group of genera together into a 
'Family' to the exclusion of others. 

 I find that it is not just Families that "may turn out to be a subset of 
another", but also a species that can evolve into another, or several.  
Does this mean that we cannot compare closely related species?  As 
I said in my previous posting, even at the species level, we cannot 
assume that they are at the equivalent level.  A protozoan 'species' 
cannot be seen in the same light as an animal 'species'.  Having said 
all that, it is quite useful to compare closely related species, genera, 
Families or whatever as long as we are aware of the limitations, and 
do not try to compare unrelated life forms at a level of equivalence.  I 
guess it is a question of the level of confidence that is placed on the 
data.  The more closely related the organism, the more reliable the 
data set.  I would like to think of classifications as being more than 
just a way in which like-minded researchers can talk to each other, 
as, I'm sure, many do.  I don't know where this puts me on the Benton 
debate, but I hope to find the time to read it soon.

Neil