Mime-Version: |
1.0 |
Sender: |
|
Subject: |
|
From: |
|
Date: |
Mon, 4 Jun 2001 19:04:05 -0400 |
Content-Type: |
text/plain; charset=us-ascii |
Reply-To: |
|
Parts/Attachments: |
|
|
>My taxonomic question deals with how do they determine rankings for any group of similar organisms? For instance, is the degree of similarity and differences within the family Donacidae, the same as within the family Turridae? Or going outside of the mollusca, the insect family Carabidae, or even the plant family Cucurbitacea? Is it possible that a range of differences that might warrent generic or subfamily ranking in one phylum could be given family or superfamily ranking elsewhere?<
Yes, the decision as to what is a genus, family, order, etc. is somewhat arbitrary. Hopefully they are roughly similar for closely related taxa, but comparision of plant and animal families is probably not too meaningful. DNA does not particularly help, as the level of variability is different for different taxa.
Dr. David Campbell
"Old Seashells"
Biology Department
Saint Mary's College of Maryland
18952 E. Fisher Road
St. Mary's City, MD 20686-3001 USA
[log in to unmask], 301 862-0372
Fax: 301 862-0996
"That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks"-P.G. Wodehouse, Romance at Droigate Spa
|
|
|