Before Mr. Campbell points this out, I may as well add that populations are
used to distinguish fossil species as well as modern ones. That is, the
discerning paleontologist does not just look at individual shells in trays,
but at whole populations, which ideally are collected from single layers at
single sites, and therefore may represent breeding populations. We not only
have geography to contend with, but time (stratigraphy) as well. And we
expend a lot of effort trying to figure out how much mixing of different
populations may have occurred.

I liked F. Titselaar's Vita Marina article very much. And I agree with part
of what Art Weil says: It would take a Mark Twain to define "species"!

"A species, by any other name, would smell as sweet."--Shelliam Wakespeare

"A species is a species is a species."--Gertrude Conch

"A species is what a taxonomist says it is."--Old maxim among taxonomists

Andrew K. Rindsberg
Geological Survey of Alabama