On Sun, 19 Apr 1998 20:40:47 -0500, Glenn Morton wrote:
[...]
>>GM>It was found in 1972 not 1993.
>SJ>I said it was "*dated* 1993". My point was that it is 5-6 years
>>old and has not apparently been mentioned in journals since.
GM>Stephen, it was mentioned in 1972. Why do you keep missing >this?
The article is P. F. A Maderson, "On How an Archosaurian >Scale Might
have Given Rise to an Avian Feather," The American
>Naturalist,106(1972):424- 428, p. 424-425
I don't " keep missing this" at all. I accept fully that "it" (ie,
"Longisquama insignis") was found in 1972 not 1993". My point is
that it was found in "1972"* and was virtually ignored for 20 years
until "1993". And for the last five years it has been virtually
ignored since.
*Actually it was first described in *1970* so it was probably found
even before then:
"These authors point to small Triassic basal archosaurs such as
Longisquama (Sharov 1970..." (Feduccia A., "The Origin and Evolution
of Birds," Yale University Press: New Haven CT, 1996, p86)
GM>And it was mentioned, as I said, a few weeks back in Nature. >Two
guys accept it two guys didn't.
It is often several months before NATURE is received here in the
Antipodes. I would therefore appreciate you posting exact
references, and even a quote, please. Thanks.
[...]
>SJ>I said it was "a non-English speaking *journal*". I did not say
>>that the article itself was not in English. Your quote from it was
in >>English.
GM>Then it is accessible to an english speaking individual.
I did not deny that "it is accessible to an english speaking
individual". My point was that it did not feature in a mainstream
"English speaking journal" like SCIENCE or NATURE.
>SJ>You just ignore my main point: "Do you seriously think that if
>>*real* half-scales/half-feathers had been found *six years ago* it
>>would not have been trumpeted from the evolutionary rooftops >>and
republished in SCIENCE and NATURE?"
GM>Once again, Stephen, it wasn't found 6 years ago. It was found
>26 years ago. What is your problem with the number 6?
I have no "problem with the number 6". I accept that Longisquama
insignis wasn't found 6 years ago. Indeed, it was described *28*
years ago, so this makes it even worse for your case. My point was
that it has been virtually ignored by most evolutionists ever since,
so you can hardly blame Christian apologists for ignoring it also.
>>GM>Since I don't really give much credence to what Gish says
>>>when he hasn't even mentioned Longisquama in any of his
>>>writings...
>SJ>Probably the reason that "Gish...hasn't even mentioned
>>Longisquama in any of his writings" is that apparently no one else
>>apart from Feduccia and Wild have either!
GM>You forget Maderson.
I don't "forget Maderson". Even he sounds tentative about it: the
title of his 1972 article was "On How an Archosaurian Scale MIGHT
have Given Rise to an Avian Feather" (my emphasis). The point is
that only a handful of scientists claim that Longisquama insignis is
an example of a scale turning into a feather. The vast majority have
ignored it. Longisquama does not even rate a mention in Colbert's or
Carroll's vertebrate paleontologies. Stahl just ignores it in her
discussion of the origin of feathers. The most recent Scientific
Amercian article of the origin of birds and flight ignores it. So
why should Christian apologists like Parker and Gish mention it?
>SJ>No doubt they bear a "resemblance to feathers" but so does a
>>balsa wood glider have a resemblance a jumbo jet! It's what Behe
>>calls a Calvin and Hobbs argument:
GM>That is my point, the scales of Longisquama do resemble feathers.
>Thank you for agreeing with my point, finally.
That wasn't your "point" at all. Your "point" was that Longisquama
was a "true transitional form...(that is, in the sense
of...containing incipient, developing or transitional structures-
such as half- scales/half feathers...":
---------------------------------------------------- Date: Sat, 04
Apr 1998 14:09:16 -0600 To: evolution@calvin.edu From:
grmorton@waymark.net (Glenn Morton) Subject: half-evolved feathers
[...]
I just ran into the following data which contradicts one of the
favorite anti-evolutionary claims. The claim is as follows, Morris
and Parker state,
"There are no true transitional forms (that is, in the sense of forms
containing incipient, developing or transitional structures - such as
half-scales/half feathers, or half-legs/ half wings) anywhere among
all the billions of known fossil forms." ~Henry M. Morris and Gary
E. Parker, What is Creation Science?, (El Cajon: Master Books,
1987), p. 11
Feduccia and Wild relate:
"Megalancosaurus, in combination with Longisquama, a Lower Triassic
thecodont with featherlike scales and furcula, render this group
(basal archosaurs, including thecodonts) the most liekly candidate
for proximity to avian ancestry."~A. Feduccia and R. Wild, "Birdlike
Characters in the Triassic Archosaur Megalancosaurus,"
Naturwissenschaften, 80(1993):564-566
It would appear that the antievolutionary claim is not verified by
observational data.
----------------------------------------------------
Now you are just claiming that "the scales of Longisquama" only
"resemble feathers." Big deal! The mere fact of resemblance means
nothing. Such resemblance could be just *analogy* (ie. convergence
due to common function), rather than *homology* (ie. inherited due
to common descent):
"Homologous and Analogous Structures Structures that are derived from
a common ancestor are called homologous structures. Among adult
terrestrial vertebrates, we can note that their forelimbs are
organized similarly and contain the same bones (fig. 20.8), even
though the animals themselves are adapted to different ways of life.
The explanation for this remarkable unity of plan is that these
vertebrates are descended from a common ancestor. The basic forelimb
plan originated with this ancestor, and was modified in the
descendant groups as each one continued along its own evolutionary
pathway. Sometimes organisms have structures that are constructed
differently but appear to be similar because they serve the same
function. An insect's wing is a stiffened membrane supported by
veins with hardened walls. A bird's wing has an internal bony
skeleton covered by muscle, skin, and feathers. Even so, both types
of wings have the same broad flattened shape because they enable the
animal to fly through the air. Structures such as these that serve a
similar function but are not derived from a common ancestor are
called analogous structures..." (Mader S.S., "Biology", 1990, p299)
The real question is whether these scales that superficially resemble
feathers really are on the way to becoming feathers, or whether they
are just are unusual scales that just look a bit like feathers.
The best that can be said of Longisquama is that it is a
"reconstruction" of a single "crushed" specimen that is *thought* by
some "to possess a unique gliding adaptation, a double series of long
scalelike structures that were unfolded in butterfly fashion to form
a gliding wing" (Feduccia A., 1996, pp87-88).
The fact is that being a single specimen, there is no evidence that
Longisquama left any descendants:
"Neither the genetic information of living subjects nor the
fossilized remains of dead ones can explain in isolation how, when
and where populations originated. But the former evidence has a
crucial advantage in determining the structure of family trees:
living genes must have ancestors, whereas dead fossils may not have
descendants. Molecular biologists know the genes they are examining
must have been passed through lineages that survived to the present;
paleontologists cannot be sure that the fossils they examine do not
lead down an evolutionary blind alley." (Wilson A.C. & Cann R.L.,
"The Recent African Genesis of Humans," Scientific American, Vol.
266, No. 4, April 1992, p22)
The same warning that du Nouy made 40 years ago about Archaeopteryx
applies even more to Longisquama:
"...An animal displaying characters belonging to two different groups
cannot be treated as a true link as long as the intermediary stages
have not been found, and as long as the mechanisms of transition
remain unknown." (du Nouy L., "Human Destiny," 1947, pp71-72)
>SJ>That in fact is *precisely the point*! Gish has no need to refer
to >>Longisquama because apparently no one else apart from Feduccia
>>and Wild does. The recent article "The Origin of Birds and Their
>>Flight," Scientific American, Vol. 278, No. 2, February 1998, by
>>K. Padian & L.M. Chiappe does not mention Longisquama at all,
>>even though it discusses the origin of feathers.
GM>Feduccia is one of the two most widely acknowledged experts on
>avian evolution. The other one is Martin.
No one doubts Feduccia's is one of the "widely acknowledged experts
on avian evolution". But his claim that birds did not descend from
diniosaurs is a *minority* position. Christian apologists have no
need to defend the faith against, or relate the faith to, minority
positions. Indeed, if they did, evolutionists would just respond,
"You're picking on a minority position"!
BTW, you just ignore that two other "widely acknowledged experts on
avian evolution", Padian & Chiappe did "not mention Longisquama".
>SJ>And BTW, it's a bad habit of yours to assume that you are the
>>only one being serious, and those who criticise your posts are just
>>"playing games". I assure you that in criticising the theistic
>>naturalistic evolution that you espouse, I am being *deadly*
serious!
You just ignored this too!
>>GM>By the way, as I pointed out the earliest english account of
>>>Longisquama is in 1972 and anyone with an ounce of curiosity
>>>could order the russian journal and look at the pictures. I have.
>>>Gish et al didn't.
>SJ>How do you *know* that "Gish et al didn't" "order the russian
>>journal and look at the pictures"?
GM>If he looked at them, then he didn't mention it. Is this better?
It is "better" but then what exactly was your point? Does Gish have
to "mention" *every* journal he orders and looks at?
Having said all that, I repeat that my Mediate Creationist position
does not deny that there may well have been "true transitional forms
(that is, in the sense of forms containing incipient, developing or
transitional structures-such as half-scales/half-feathers, or
half-legs/ half-wings)". God may have created feathers de novo or He
may have created by modifying existing designs. In both cases it
may have been so rapid and directional that it left few traces in the
fossil record of the actual transition event(s).
Steve
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Stephen E (Steve) Jones ,--_|\ sejones@ibm.net
3 Hawker Avenue / Oz \ Steve.Jones@health.wa.gov.au
Warwick 6024 ->*_,--\_/ Phone +61 8 9448 7439
Perth, West Australia v "Test everything." (1Thess 5:21)
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