On Sat, 14 Sep 1996 15:49:59, Glenn Morton wrote:
[...]
SJ>But I am not a YEC like Gish and will concede that this is good
>evidence for an "unknown fish common ancestor" between the
>lobe-finned fishes and the tetrapods....even though there still may
>be major problems in time-frames if the earliest lobe-finned fish
>are contemporaneous with the earliest tetrapods. In "this argument"
>we had "here a year ago", Ashby Camp posted:
>--------------------------------------------------------
>As Ahlberg and Milner point out (p. 507), the oldest
>panderichthyids currently known date from the Lower Frasnian (Upper
>Devonian - about 375 mya). There is solid evidence, however, for
>the existence of tetrapods back to the Lower Devonian, some 25
>million years earlier (Anne Warren, Robert Jupp and Barrie Bolton,
"Earliest tetrapod trackway," _Alcheringa_ 10: 183-86 [1986])....
>--------------------------------------------------------
>
>If indeed tetrapod tracks exist from "the Lower Devonian, some 25
>million years earlier" than "the oldest panderichthyids...from the
>Lower Frasnian (Upper Devonian...), then there is still a chronology
>problem....
GM>To use the Warren, Jupp and Bolton article as proof of Lower
>Devonian tetrapods is almost laughable. The rock containing the
>tracks was found in the courtyard of a house built (I believe, i
>didn't look it up) in the latter part of last century. They guessed
>that it is lower devonian but aren't really sure. The authors state
>that no digits are preserved in the tracks and so they aren't sure
>that it is even a tetrapod!
Glenn's heavy handed response is noted! :-) Nowhere did I say that
the "Warren, Jupp and Bolton article" was "*proof* of Lower Devonian
tetrapods". I said (quoting Ashby Camp - a former Reflectorite) only
that it was "solid *evidence*...for the existence of tetrapods back
to the Lower Devonian"
GM>So you are citing a case where the authors don't know where the
>rock came from, what age the rock really is, and aren't sure that it
>is even a tetrapod....
Sure, but it is not as bad as Glenn makes out. Here are some
excerpts from his original posts in debating with Ashby, with my
emphases:
----------------------------------------------------------------
Date: Thu, 22 Jun 1995 23:44:47 -0400
From: GRMorton@aol.com
Subject: Re: Panderichthyids and trans...
...There are several things wrong with Warren's et. al claim.
First, the track way was found on a slab in the courtyard of a house
built in 1873. (above ref. p. 183) THEY DID AN ADMIRABLE JOB OF
TRYING TO FIND WHERE THE ROCK CAME from, but they were unsuccessful
They state," We have located several quarries in the Mt. Bepcha
region, but at the time of writing have not been successful in
determining the source of the courtyard flagstones."
Thus, while they believe that the flagstones came from the Grampians
Group, THERE REMAINS A SMALL DOUBT. This means that THERE IS SOME
UNCERTAINTY in the age.
Secondly, there are no digit impressions preserved. No toes. Thus WE CAN NOT
BE CERTAIN that a tetrapod made the track. They state,
"No digit impressions are preserved and there is no tail or body
trace. Because of this THERE IS NO CERTAINTY that the marks form a
tetrapod track, but their highly regular nature indicates that they
do." p. 184.
----------------------------------------------------------------
Not all that bad, is it? Note Glenn's own words "there remains a
small doubt...there is some uncertainty...thus we can not
be certain...there is no certainty". There is *evidence* for
tetrapods in the "Lower Devonian" but no certain *proof*. That is in
fact all that I was claiming.
Here is another post from Glenn:
----------------------------------------------------------------
Date: Thu, 6 Jul 1995 07:02:10 -0400
From: GRMorton@aol.com
Subject: first vertebrate tracks
...Keith Stewart Thompson wrote: "As long as the geological age of
the reported 'Early Devonian' trackways from Australia is TENTATIVE
and no skeletal remains are known, to conclude that tetrapods arose
in, and radiated from, East Gondwana is PREMATURE." K. S. Thompson,
"The Origin of the Tetrapods," American Journal of Science 293-A, p.
52 [1993] and "I AM PERSONALLY INCLINED to discount the 'Early
Devonian' trackway from Australia and would place the origin of
tetrapods at late Middle Devonian." IBID., p. 53
----------------------------------------------------------------
Again, the trackway evidence is only "tentative" and it is merely
"premature" at this stage to "conclude that tetrapods arose in...
(the) Early Devonian. Thompson is only "personally inclined" to
discount it.
And last but not least, Glenn admitted that this was "a possible
trackway":
----------------------------------------------------------------
Date: Fri 07 Jul 1995 12:29 CT
To: evolution@Calvin.EDU, GRMorton@aol.com
From: Glenn.Morton@ORYX.COM
Subject: first vertebrate track
..I ADMITTED THAT THIS WAS A POSSIBLE TRACKWAY but I will not admit
that it is a probable trackway and certainly we can't use this as a
proven trackway."
----------------------------------------------------------------
No doubt Glenn will point out that he did not admit it was "a
probable trackway" and we all agree that "certainly we can't use this
as a proven trackway." The point is that he does admit that it is
"a possible trackway" and that is all I was claiming. So if that is
the case then my point that: "If indeed tetrapod tracks exist from
the Lower Devonian...then there is still a chronology problem" with
the origin of tetrapods from panderichthyids (lobe-finned fishes)
because the earliest fossils of those date from the "Upper Devonian",
some "25 million years earlier".
Indeed, there is still a problem anyway, because if "Keith Stewart
Thompson" (as cited by Glenn), "would place the origin of tetrapods
at late Middle Devonian", and "the oldest panderichthyids currently
known date from the Lower Frasnian", ie. "Upper Devonian" (as cited
by Ashby and not challenged AFAIK by Glenn), then we have a
chronology problem and Pitman's point (cited by me) is still valid:
"..Since the earliest tetrapods are found in upper Devonian rocks,
contemporary with the fish from which they are supposed to have
descended, some unseen line is supposed to have evolved from
lobe-fins." (Pitman M., "Adam and Evolution", Rider & Co: London,
1984, p199)
Which simply parallels Stahl's point that "none of the known fishes"
(which includes the panderichthyids) "is directly ancestral to the
earliest land vertebrates":
"none of the known fishes is thought to be directly ancestral to the
earliest land vertebrates. Most of them lived after the first
amphibians appeared and those that came before show no evidence of
developing the stout limbs and ribs that characterized the primitive
tetrapods.' (Stahl B.J., "Vertebrate History: Problems in
Evolution", Dover 1985, pp121-148, in Johnson P.E., "Darwin on
Trial", InterVarsity Press" Downers Grove Ill., Second Edition, 1993,
p76)
GM>...as proof of the existence of tetrapods in the Lower Devonian.
>This is not good science Stephen.
See above. Note how Glenn sets up a straw man to then knock down!
:-) Neither Ashby nor I (nor indeed Warren et. al.) claim the
Australian trackway as "*proof* of the existence of tetrapods in the
Lower Devonian". My comment was cautious: "*If* indeed tetrapod
tracks exist from "the Lower Devonian...*then* there is still a
chronology problem." All that I, Ashby and Warren et. al. claimed
is that it was *evidence*.
I was under the impression that it was always "good science" to
produce *evidence* even if the evidence is inconclusive? Otherwise
what is the status of Glenn's theory, based mainly on a fragment of
a 4.2 mya hominid humerus, that comparatively modern humans existed
5.5 mya? If one is "not good science" nor is the other! :-)
God bless.
Steve
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