Re: Testing in historical science

Bill Payne (
Tue, 18 Nov 1997 23:28:24 -0600

Mon, 17 Nov 1997 23:05:33 -0600 Glenn Morton wrote:
> At 10:14 PM 11/17/97 -0600, wrote:
> >OK, I'll give you two or three, maybe more Precambrian phyla. But to
> >say that the remaining ~50 phyla appeared within ~5 million years, and
> >we have only silence (no more new phyla) and reduction in the numbers
> >during the following ~600 million years implies something other than the
> >"stately march of evolution." What ignited the explosion and then what
> >extinguished it?
> Once again, I admire your honesty on these issues. First, we do have a new
> phyla that was found just a couple of years ago. See Funch and Kristensen
> "Cycliophora is a new phylum with affinities to Entoprocta and Ectoprocta,"
> Nature 378, Dec. 14, 1995, p. 711. If I wanted to I could claim that this
> is a brand new phyla just evolved within the past few thousand years. There
> is no fossil record for this phylum!

OK, I'll rephrase my question: What ignited the explosion and then what
_almost_ extinguished it?

> >> If there is no change in morphology, there is no
> >> evolution!!!!
> >
> >Exactly. That's my point with the blue-green algae. I guess you can
> >say that they did evolve and other blue-green algae re-evolved from
> >something simpler to take their place, but that sounds like a just-so
> >story; you know - like the ones I tell.
> I will still go back to the fact that there are only a limited number of
> ways that one can connect cells up and still have an algae. These are
> sheets, lines and single cells.

Help me here, I'm missing your point. First, aren't algae colonial but
single-celled organisms? Second, wouldn't an alga be an alga,
regardless of how it is connected?

I did find one reference at the library tonight regarding blue-green
algae from the late Cambrian: "Thus, while fossil blue-green algae
occur in a great variety of shapes and sizes in the geologic record,
most of these differences are ecological and do not signify separate
species." (Fisher, D.W., Algae from Antiquity, in Conservationist 910101
Jan/Feb91, v 45 Issue 4, p42+)

My primary question at this point is: If evolution is universal, driven
by random mutations, then how could even one group, like blue-green
algae, escape the mutations? If blue-green algae did not evolve, why
not? In short, how can we have both stasis and evolution? The two seem
to be antithetical.

Bill Payne