On Mon, 12 Aug 1996 21:14:34, Glenn Morton wrote to Geoffrey Howells:
GH>Does anyone know of any other good transitional fossils?
GM>Yes I will send it to you and anyone else who wants it privately
>because we had this argument here a year ago and I don't want to
>rehash things. The fish tetrapod transition is quite smooth. Each
>species is altered in a given portion of their anatomy. The last
>fish had both gills and lungs, the first tetrapod had both gills and
>lungs. The temporal order is also quite nice.
That's interesting, because Johnson in 1993 cited Stahl as follows:
"The story to be tested is that a fish species developed the ability
to climb out of the water and move on land, while evolving the
peculiar reproductive system of amphibians and other amphibian
features more or less concurrently. No specific fossil fish species
has been identified as an amphibian ancestor, but there is an extinct
order of fish known as the rhipidistians which Darwinists frequently
describe as an "ancestral group." The rhipidistians have skeletal
features resembling those of early amphibians, including bones that
look like they could have evolved into legs. But according to
Barbara J. Stahl's comprehensive textbook, Vertebrate History,
`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
charpacterized the primitive tetrapods.' (Stahl B.J.,
"Vertebrate History: Problems in Evolution", Dover 1985, pp.
121-48)
(Johnson P.E., "Darwin on Trial", InterVarsity Press" Downers Grove
Ill., First Edition, 1991, p74)
Harvard Professor of Paleontology Stephen Jay Gould savagedly
reviewed Johnson's book in Scientific American (July 1992) and
nit-picked every scientific point he could find. He even attacked a
point on this page, but he did not contest the above. I therefore
conclude that it is established fact.
In the debate that Glenn refers to, the following quotes were
posted, which throw doubt on Glenn's "quite smooth" "fish
tetrapod transition":
"The limbs, of course, occupy pride of place in any analysis of
tetrapod origins. The pattern of internal structure of the
osteolepiform limb as in _Eusthenopteron_ [cite omitted] and
_Sterropterygion_ [cite omitted] is clearly homologous with that of
tetrapods with respect to the humerus/femur or ulna and radius/tibia
or fibula, but little else. It would also be a mistake to exaggerate
the extent to which osteolepiform fishes actually used their fins as
arms and legs; the fins in the forms that we know are all small and
feeble (compared even with the large fins of porolepiforms,
coelacanths, and the modern lungfish _Neoceratodus_, which have a
different internal structure). These fishes obviously could not live
out of water because they would suddenly be unsupported and feel the
force of gravity." (Thomson K.S., "The origin of tetrapods,"
_American Journal of Science_ (1993) 293-A:58)
and:
"In contrast, the earliest land vertebrates (for which there are
skeletal remains, i.e., _Ichthyostega_, _Acanthostega_, and
_Tulerpeton_) "had short but massive limbs of the basic pattern of
subsequent tetrapods" (Robert L. Carroll, "The Primary Radiation of
Terrestrial Vertebrates," _Annual Review of Earth Planet Science_
[1992] 20:47). These differences are so significant that Dr.
Carroll states that "no fossils are known that can be considered
intermediate between these clearly aquatic [osteolepiform] fish and
genera that are unequivocally classified as terrestrial verte-
brates" (_Ibid_., 45)"
Here is one of my own from Carroll:
"The origin of amphibians...is certainly one of the most significant
episodes in vertebrate history. The group from which they arose, the
rhipidistian sarcopterygians, were common throughout the Devonian and
lingered into the Lower Permian. Their structure is known in
considerable detail (Andrews and Westoll, 1970). Genera in which the
skeleton is appropriate for ancestors of amphibians are known from
the middle Devonian, approximately 15 million years prior to the
appearance of amphibians at the end of the Devonian (Jarvik, 1980).
These early amphibians are also known in considerable detail. Their
limbs have already achieved a typically tetrapod pattern. The
remains of rhipidistian fish are common in Middle and Upper Devonian
deposits that might be expected to yield the remains of ancestral
amphibians, BUT NO FOSSIL IS KNOWN THAT COULD BE CONSIDERED
INTERMEDIATE BETWEEN THESE TWO GROUPS." (Carroll, R.L., "Vertebrate
Paleontology and Evolution", W. H. Freeman & Co: New York, 1988,
p579. Emphasis mine)
Note: I do not rule out that tetrapods may have descended from an
unknown fish common ancestor. But I do dispute that it is quite as
"smooth" as some evolutionists like to portray it.
God bless.
Steve
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