Thanks for addressing my questions Doug.

>I have no objection to this possibility, though I do not believe it has been
>observed.  I am aware of genetic studies and zoogeographical analyses which
>would indicate that this is possible.

Assuming that by "do not believe" you mean "am not convinced" I guess we
differ on what "observed" means. There are plenty of examples of continuous
stratigraphic sequences showing divergence of species, for example in
foraminifera in deepsea cores and in diatoms from cores in lakes. Here's an
example in mollusk. In the Miocene Pannonian lake basin in Hungary, Muller
& Magyar (1991, Acta Palaeontologica Polonica 36:353-372) found a gradual
transition over time between species of cockles that were previously placed
in two different genera in different subfamilies. The lineage starts with
Lymnocardium decorum ponticum and leads to the genus Prosodacnomya.

Do you consider this kind of change through a stratigraphic sequence to be
an observation or an inference? To me it is an observation. Isn't this the
kind of evidence that you request in the case of Archaeopteryx? The lack of
known intermediates in a particular case doesn't mean that intermediates
haven't been found in other cases.

>>  What if something evolved entirely by macroevolution? Blammo, in one giant
>>  mutation, something vastly different appeared. [stuff deleted]
>
>Mutations generally do not improve a species.

I didn't say mutations improve species. I don't think they do; they merely
make them different. I'm saying, suppose that incredibly rare, one in a
quadrillion mutation occurred, and something extremely different from its
parents appear and somehow thrived. Here's a real example:

Van Valen & Maiorana (1991, Evolutionary Theory 10:71-74) named the human
cell culture line known as HeLa cells as a new family, genus and species:
Helacytidae, Helacyton gartleri. These amoeboid cells are derived from a
carcinoma in Henrietta Lacks in 1951. They have somehow been immortalized
so that they can keep dividing, rather than dying after 50 or so divisions
as do most cell culture lines. The number and organization of chromosomes
is different than in humans. HeLa cells invade other tisse cultures, and
have become pest in the laboratory, expanding their range from North
America to other continents. They can no longer interbreed with their
parent species. (Human giving rise to amoeba--sounds like something that
happened in Art Weil's basement.)

If an example of a change of a similar order of magnitude (phylum to
phylum) could be found outside the laboratory (morphology saying one thing,
genetics saying another), would that be evidence of macroevolution?

Gary

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