Re: species flock -Reply

[WndrKdnomo@aol.com]

In a message dated 11/10/98 6:39:45 PM, William_Vannerson@ama-assn.org writes:

<<"A species flock is a group of closely related species all living in the
same ecosystem. As Greenwood (1974: 19) emphasized, "The term
'species flock' . . . should, strictly speaking, be applied to a species
assemblage of monophyletic origin." The clear implication, then, is that a
species flock evolved within the ecosystem from a single ancestral
species by repeated speciation events.>>

I don't see, by these standards, how this concept of "species flock"can be
applied to the genus Apistogramma.  In the first place, most species do not
share the same ecosystem, that is , they are found in different rivers, even
different drainages.  I think it would be a huge stretch to count the Amazon
Basin as one ecosystem. Secondly, as far as I know, those species that are
found together are not the most closely related species.  (Others will know
better than I on this point, but it is important).  Thus, they fail on two
counts.
A much better example would be the Galopogos finches, where a large number of
current species obviously evolved from a single species. In terms of the Rift
lake cichlids, there can probably be a case made for a number of species
flocks in each lake.  The implication is  that when the lakes where formed
there were originally only a few species present, each of which spawned a
"flock" of related species to fill available ecological niches.
Anyway, this is how I interpret the situation, based on the material quoted
above.
Jeff


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