Secondary Addiction Part III: Ann Coulter on Evolution
By
James Downard
Posted July 25, 2006
1. Coulter's Archaeopteryx quote
2. The Bermuda triangle defense
3. Mesozoic birds
4. Jonathan Wells to the test
5. The dinosaur connection
6. Feathers
7. References
Following her discussion of dinosaurs examined in Part II of this
series, Coulter (2006, 219) ventured this:
For over a hundred years, evolutionists proudly
pointed to the same sad birdlike animal, Archaeopteryx, as their lone
transitional fossil linking dinosaurs and birds. Discovered a few years after Darwin published The Origin of
Species, Archaeopteryx was instantly hailed as the transitional species
that proved Darwin's theory. This
unfortunate creature had wings, feathers, teeth, claws, and a long, bony
tail. If it flew at all, it didn't fly
very well. Alas, it is now agreed that
poor Archaeopteryx is no relation of modern birds. It's just a dead end. It
transitioned to nothing.
But could Archaeopteryx be our one example
of bad mutations eliminated by natural selection? Archaeopteryx can't fill that role either, because it seems to
have no predecessors. The fossils that
look like Archaeopteryx lived millions of years after Archaeopteryx, and
the fossils that preceded Archaeopteryx look nothing at all like it. The bizarre bird is just an odd creation
that came out of nowhere and went nowhere, much like Air America Radio.
Where should one begin with this?
Her lame rhetoric, to start. As
with Tiktaalik in the previous posting, Coulter indulges in hyperbolic
adjectives the moment she encounters something she doesn't understand. This is especially true if it fits a
Darwinian model (which the paleontology does, after all). Apparently the evolutionary significance of Archaeopteryx
can we waved away more easily if only it is deemed a sufficiently "poor,"
"sad," unfortunate," and "bizarre" beast.
Because Coulter knows absolutely nothing about taxonomy, and could not
have read anyone in the design literature who might have educated her, it is
understandable (although again hardly excusable) that she can describe Archaeopteryx's
"bizarre" anatomy so glibly.
For comparison, paleontologist Chris McGowan (1984, 116-117) had already
passed through this area, describing thirteen anatomical features
distinguishing reptiles from birds, involving the hip, chest and abdomen, the
vertebral structure, hand, ankle and tail, and feathers. Of these, Archaeopteryx possessed
exactly two distinctly avian elements (a wishbone and feathers) -- all the
remaining characteristics were specifically and uniquely reptilian. Paleontologists have since confirmed many
theropod dinosaurs had furcula, such as Norell et al. (1997), meaning
that bird component too had antecedents among the diapsid archosaurs, and the
very recent discovery of feathered dinosaurs will be discussed shortly.
Needless to say Coulter didn't even try to cite any actual
paleontologists or taxonomists who assert that Archaeopteryx isn't the
first bird that happens also to be squarely reptilian. Thus Lambert & The Diagram Group (1990,
121) listed the archaeopterygid family generally among the theropods; the
recent cladistic analyses by Fastovsky & Weishampel (1996, 300-309), Kevin
Padian & Luis M. Chiappe, "Bird Origins," in Currie & Padian (1997,
71-79), or Dingus & Rowe (1998, 180-194), specifically group them as avian
maniraptorans.
But for Coulter, dead from the neck up when it comes to speculating on
the dynamic nature of life, such comparisons are as rare as Castro tolerating a
critical press.
We'll get to more of the forensic details of how "bizarre" Archaeopteryx
is momentarily, and just how "unrelated" it is to other critters known to
science. But first the scholarly trail
has to be marked: not unusually for her, Coulter did not offer any references
for her claims. So where did she obtain
her understanding about the pathetic, lonely Archaeopteryx?
Her acknowledged tutors (Behe, Berlinski and Dembski) have contributed
nothing on these matters in their published oeuvres. David Berlinski is a special case, though, as I happen to know
that he is theoretically aware of much of the information you are about to
read. And the reason I know this is
because, a few years ago, I sent it to him -- at his specific request. That none of these data filtered through to
Coulter suggests two pedagogical possibilities (not mutually exclusive): that
Berlinski has no skill at retaining or communicating relevant subject matter,
and Coulter is one pretty dull student.
Back to the source hunt. While
she is aware of Philip Johnson's Darwin on Trial, that author could not
be the font of her misunderstanding either, as he has been only marginally more
wordy than the DI tutors. The brief
meaningless concession of Johnson (1991, 79), that "Archaeopteryx is on
the whole a point for the Darwinists," evidently got snatched back by the time
Johnson (1997, 51-52) intimated profound uncertainty as to "how things like
birds come into existence in the first place." At no point had Johnson ever examined the actual evidence of bird
evolution (which as we shall see, had got rather big by 1997).
That leaves, among works Coulter has cited, the Duane Gish of
Intelligent Design, the detail fiddling Jonathan Wells (2000). It turns out all of her misconceptions and
misinformation about Archaeopteryx can be traced directly to that
wellspring of pseudo-paleontology.
Before we commence that analysis, though, we have to clear another of
those significant conceptual hurdles that plagues antievolutionary discussion
of paleontology. Much as with
biogeography/speciation in the last installment of this series, there is a
gigantic piece missing from the antievolutionary conceptual kit: geological
context. This omission is so ubiquitous
and so important for understanding how evolution critics can be so clueless,
that I have a special name for it: the Bermuda Triangle Defense.
I call it that because it makes it easy to recall what is going on
here. Bermuda Triangle believers are
fond of calling attention to the "mysterious ship disappearance" on the night
of such-and-so. What they invariably
fail to note is that the worst hurricane in decades tore through the region on
the night in question, and so may have contributed to that "mysterious"
disappearance.
Now it doesn't matter technically whether the writer didn't know about
the hurricane, or knew about it and suppressed the information. While that makes a big difference for ethical
turpitude, it doesn't change the fact that the hurricane wasn't discussed,
and therefore all conclusions are called into question on that account.
Bringing up fossil evidence and talking about the supposed absence of
relatives without delving into whether it would be even slightly likely that
such would be preserved (independent of whether they actually had existed)
constitutes the Bermuda Triangle Defense.
Now let's fill in the particulars for Archaeopteryx.
Back in the Jurassic period, 150 million years ago, "Europe" consisted
of a series of islands dotting the giant Tethys Sea that stretched between
Africa and what then existed of Asia (the subcontinental raft of India was
still parked down by Madagascar in the Southern Hemisphere).
In the million-odd centuries since (and isn't that a long time?)
tectonic movements have done their damaging work. Much of whatever real estate was dotting the Tethys Sea has been
lost to plate subduction or erosion. But eventually one miniscule fragment of one of those Tethyan islands
ended up folded in a corner of Bavaria, providing one brief snapshot of life
that got caught in a poorly aerated lagoon. Called the Solnhofen, this is where all the known fossils of archaeopterygids
are to be found: to date, exactly seven -- plus one feather impression. See Hartmut Haubold, "Solnhofen Formation,"
in Currie & Padian (1997, 676-677) for its geology, fauna and
paleoenvironment, and Benton (1996, 88-89) for a summary of the Jurassic
landscape with map.
The significance of this forensic fact cannot be overstated. The Solnhofen is an example of an incredibly
rare form of deposition, so special there is even a five dollar word for it: Conservation
Lagerstätten -- a fancy German term that may be commonly translated as "mother
lode" deposits.
By the way, I imprudently included these useful and appropriate
geological terms (Conservation Lagerstätten, plate subduction and
erosion) in a recent email inquiry to William Dembski, trying to ascertain the
exact nature of his tutorial interlude with Coulter. (Dembski's "response" is described in a separate Talk Reason
posting.) In the interest of fair
warning, I am signaling a DEMBSKI ALERT at each instance in this and subsequent
essays where I have occasion to utilize one of the horribly big words I
attempted to discuss with him.
Now for an interesting forensic question: were there only just seven Archaeopteryxes
alive in all history? Kent Hovind
thinks that, as Frank Sonleitner reminded me apropos "Maintaining Creationist
Integrity", a
criticism of Hovind by fellow creationists at Answers in Genesis.
Other creationists (YEC or OEC) have yet to venture an opinion here, nor
have any Intelligent Design advocates. But evolutionists would rate the idea as highly unlikely. Even though no fossils exist to prove it,
they infer that this earliest known bird had close relations within its genus,
and that these had to have had parents -- and string enough of those together,
pretty soon you have the possibility of modified ancestors. Naturally evolutionists expect that
ancestral chain to have looked even more unlike later birds, and more
like a linking reptile, than the archaeopterygids did. The problem with settling this side of the
equation is that the odds of encountering their fossils are incredibly remote,
since there are no other suitable Lagerstätten in the preceding Jurassic
(or Triassic, for that matter).
Add to that, small flyers are among the worst candidates for successful
preservation in any event -- as the sketchy fossil record for birds and bats
confirms. Stahl (1985, 362) noted the
obstacles facing the preservation of fossil birds, which may have inspired
Johnson (1991, 79) to concede that "birds pursue a way of life that ensures that
their bodies will rarely be fossilized."
But let's suppose luck was with the paleontologist, and some of the
revealing evolutionary ancestors of Archaeopteryx had successfully
entered the fossil record. How likely
would it be for them to make it all the way into a museum display case, for
Coulter not to pay attention to today?
Like everything else, islands are subject to erosion, and the subsequent
geological history of the region hasn't helped. When the African plate plowed into Europe tens of millions of
years later, masses of real estate were mangled into the new Alps -- resting as it
does on the African plate, geologically speaking, Italy is not actually a part
of Europe. The result of this collision
was a lot of obliterated landscape.
Then consider the scouring action of several ice ages. Just think of all the debris that had to be
removed from the sides to leave the distinctive Matterhorn sticking up
afterward.
Even should the evidence have made it that far, there was still the
lamentable likelihood of slightly-missed timing, with the vital clue eroding
from some hillside centuries ago, to dissolve unnoticed into dust long before
the 1860s, when living paleontologists began poking around the Solnhofen.
These are simply the bald facts of geology, which anyone whose
understanding of paleontology was not "poor," "sad" or "unfortunate" should
have known.
The problem for antievolutionists is that none of them ever apply
this insight to ascertain whether there are solid reasons why the once-living
members of Archaeopteryx's genus (let alone any possible "ancestors")
may not have ended up preserved for us to see. The pattern is absolutely consistent for antievolutionary works that try
to use Archaeopteryx as Coulter does. That includes the various Institute for Creation Research (ICR) efforts
by Henry Morris (1985), Morris & Gary Parker (1987) and Duane Gish (1990;
1992; 1993; 1995). Also the orbiting
YEC authors Ankerberg & Weldon (1998), Wendell Bird (1989), Davis &
Kenyon (1993), Hank Hanegraaff (1998), Scott Huse (1997), James Perloff (1999)
and Luther Sunderland (1988). And
likewise for Michael Denton (1985), Alan Hayward (1985), Cornelius Hunter
(2001; 2003), Phillip Johnson (1991) and Richard Milton (1997), variously
circulating around Intelligent Design.
That the Bermuda Triangle Defense is alive and well is also illustrated
by Coulter's putative source Jonathan Wells (2000, 112-113) when he highlighted
exactly the feature of the Solnhofen that precluded the preservation of earlier
fossils, yet never made the connection:
The Solnhofen limestone, in which all eight
specimens of Archaeopteryx were discovered, is from the geological
period known as the Upper (or Late) Jurassic, about 150 million years ago. This makes Archaeopteryx the earliest
known bird -- or at least, the earliest undisputed bird. Several specimens of it -- especially the Berlin specimen -- are also
among the most beautiful fossils ever found. The Solnhofen limestone is so fine-grained that it is quarried for use
in the printing process known as lithography, and it preserved Archaeopteryx
in exquisite detail -- right down to the structure of its feathers.
Because of the vagaries of fossil preservation, Archaeopteryx is
likely to remain an isolated example in the Jurassic landscape, and hence a
forensic bottleneck. Archaeopteryx
could have been very typical of what was going on in the Late Jurassic -- or very
unusual. But while there is simply no
way to know precisely how diverse its family was, there are plenty of ways to
put some boundaries down and make sense of what we do know.
We can start with feathers. As
it happens, isolated feathers are more likely to be shed -- and perhaps
sporadically preserved -- the more feathered animals there were (whether birds or
their potential non-bird relations). Gregory
Paul (1988, 63, 66) has noted that stray feathers do indeed show up in the
following Cretaceous Period, and that this is a circumstantial clue that
neither birds nor protoavians could have been particularly abundant prior to Archaeopteryx. See also the Chatterjee (1997, 132-135)
survey of fossilized feathers and feather impressions.
This means that whatever was going on with feathered critters, Archaeopteryx
was most certainly very close to the root of it.
This brings up a relevant question for the design argument. Just as rocks are likely to have dropped
back in the Mesozoic exactly as they do today, accelerating under gravity, is
there any reason to suppose -- even in a "designed" system -- that animal diversity would
(or even could) have been noticeably more barren back then? That is where an appreciation of speciation
and current biogeography is an essential prerequisite to thinking clearly about
fossil evidence. Could even a designed Archaeopteryx
have been prevented from speciating? Or
from having descended, by that same microevolutionary means, from an immediate
species ancestor?
This is no academic question. For as it happens, even in that highly restricted Solnhofen snapshot,
the latest of the archaeopterygid specimens differs from its fellows sufficiently
to warrant its placement as a second species within the genus. One with even more interesting anatomical
features, as Pat Shipman (1998, 45) noted in her work on the archaeopterygids:
It provided three surprises, new features
that significantly altered the view of Archaeopteryx. The skeleton is very small -- even smaller than
the Eichstätt specimen -- but apparently adult. This has led Peter Wellnhofer, the German paleontologist who described
it, to suggest that it represents a new species, Archaeopteryx bavarica. Apart from size, the specimen includes two
new anatomical features: a bony sternum, which is unknown in any other specimen
and is crucial for the attachment of flying muscles; and a set of bony,
interdental plates that are preserved on the inner side of each lower jaw
between all tooth positions. Similar
interdental plates are found in two different groups that have been suggested
as possible ancestors for Archaeopteryx: the theropod dinosaurs and a
still more primitive reptilian group, the thecodonts.
See also Feduccia (1999, 77) and Elžanowski (2001).
Thus we know -- not an opinion -- that more than stasis was at play back when
"poor" "sad" little Archaeopteryx was flapping about. And we should probably note also that while
Archaeopteryx was likely a poor flyer by comparison to modern birds,
it would have been among the most effective airborne predators of its time.
Since Jonathan Wells had cited Shipman's book, we can ask why he failed
to follow this trail of clues? Apart, I
mean, from complete lack of curiosity and theoretical stupor. Presuming Wells was Coulter's sole source we
can, however, spy just how Coulter managed to get so uninformed here. But that doesn't mean we can't go where
Coulter or Wells fear to tread. Let's
fill in some more missing details.
For about a hundred years the record of fossil Cretaceous birds had only
two characters: the waterfowl Ichthyornis and Hesperornis, with
only one of those genera turning up from the critical Early Cretaceous (still
many millions of years after the Solnhofen time slice). But all that began to change in the 1980s,
when the number of available specimens first doubled, then doubled again during
the 1990s. For some of the characters,
see Chiappe (1995a,b), Hou et al. (1995; 1999), Fastovsky &
Weishampel (1996, 314-321), Gibbons (1996) re Hou et al. (1996), Luis M.
Chiappe, "Aves" in Curie & Padian (1997, 32-38), Shipman (1997), Padian
& Chiappe (1998), Dingus & Rowe (1998, 212-228), Ackerman (1998) or Dinosaur
(2001, 138-143).
Meanwhile Phillip Johnson (1991, 78) whistled through the dark in Darwin
on Trial: "The new specimens have reptilian skeletal features which qualify
them as possible intermediates between Archaeopteryx and certain modern
birds. The evidence, however, is too
fragmentary to justify any definite conclusions." Johnson artfully declined to discuss any of these features, by
the way. Nor has he filled in that
particular "gap" in the fifteen years since.
We may start with Scott Huse (1997), recommended in the "Bedtime
Christmas Readings" for December 1999 by Cato Institute pundit Doug
Bandow! In March 2001 I emailed Bandow
asking whether he was familiar with the background of any of the books he
cited. He replied that he "found them
to be better argued and researched than the typical 'creation science' and
young earth tracts, which aren't well-founded." Bandow seemed casually unconcerned when informed that Huse
happened to be not only a Young Earth Creationist, but one regarded as dippy
even by fellow YECers, such as Carl Wieland (1998) at Answers in Genesis.
Nor did British Mensa website editor Richard Milton (1997) think to
discuss the new birds. Or Bible Answer
Man Hank Hanegraaff (1998), with a glowing Foreward by Phillip Johnson one may
note. Or creationist apologists
Ankerberg & Weldon (1998) and Perloff (1999), or Design apologist Cornelius
Hunter (2001; 2003). Once again,
Coulter's putative source Jonathan Wells (2000, 120-121, 296-297) veered the
closest when he sported a chart on "Cladistic theory and the fossil record"
that had several black bars representing "groups of extinct birds." But none of these Cretaceous birds were identified,
and his text didn't explain anything about them.
Now we may add Coulter (2006) to this parade of antievolutionary
research anoxia.
Had any of these authors thought to investigate this matter in the hope
that these Mesozoic flyers might pose a problem for evolution, they would have
been in for a big disappointment. The
Cretaceous birds were picking up right where Archaeopteryx left off.
The Early Cretaceous Eoalulavis, discovered in Spain in 1996,
proved to be the earliest bird with an alula steering feather -- and it was
attached to the theropod digit I it still retained from its reptilian
ancestors, Padian (1996) on Sanz et al. (1996), and Chiappe (1998,
31). Cf. Zhang & Zhou (2000,
1956-1957).
As the fossils turned up, they have documented how -- step by incremental
step -- they were losing their theropod features: the specialized gastralia bones
lining the belly wall, their tails, and eventually their teeth. Concurrently, they retained their hollowed
bones, their keeled sternum got bigger, the forearm lengthened, and the fingers
of their theropod hand embarked on the carpometacarpal fusion that makes a
modern chicken wing such a bony treat.
And remember that tail Coulter mentioned so casually regarding "sad" Archaeopteryx? On the genetic side, Richardson et al.
(1998, 154) spotlighted some of the developmental processes that may have
contributed to the observed reduction of tail vertebrae in fossil and living
birds. In the missing out on his own
sources department, Wells (2000, 289) had even cited the Richardson
paper in his evasive take on Haeckel's embryo drawings but failed (as usual) to
connect the dots here.
And remember those teeth that Coulter also mentioned, and which (like
the tails) disappeared among the Mesozoic birds? By some curious coincidence, modern birds still retain the genetic
mechanisms for making teeth, as evidenced by Kollar & Fisher (1980), Chen et
al. (2000), Narayanan et al. (2001) and Mitsiadis et al.
(2003). If modern toothless birds were
created independently of their ancient toothed counterparts, why would a
designer have deliberately (maliciously?) equipped them with unnecessary
genetic systems for making teeth? Was
the fellow a dimwit, or perhaps again it was a case of the designer admiring
Darwin so much that he liked making 21st century evolutionary geneticists as
happy as possible?
But thinking about such things cannot start among people who can't even
get to the "noticing the data" stage. As it happens, right after mangling Tiktaalik, Coulter (2006,
228) actually cited Stephen Jay Gould (1983, 298) for an authority quote on the
"trade secret of paleontology" being the comparative scarcity of
species-species transitions in the fossil record. (Yet another Bermuda Triangle Defense subset, by the way, as rare
doesn't mean non-existent. We'll
delve into the particulars of species transitions, fossil and living, in a
later Coulter installment.)
Coulter's problem here is that this quote came from a book rather
conspicuously titled Hen's Teeth and Horses Toes. Apparently that was insufficient prodding
for her to notice Gould (1983, 182-184) discussing the Kollar & Fisher
paper. Further indication of the
ignorance/lazy factor here: the three recent PNAS works aren't even hard to
find, as full text is available at pnas.org online. Point mouse ... click, click.
The record holder for not discussing the point here must fall to Phillip
Johnson though. Not only had Johnson
(1991, 157-158, 165-167, 172, 185, 187) repeatedly cited two works where
Kollar & Fisher had come up, Futuyma (1982, 48) and the aforementioned
Gould. Johnson (1995, 228) even
returned to the scene of the crime by directly alluding to Ken Miller (1994)
having brought up "so-called hen's teeth"! About which information Johnson successfully contributed absolutely
nothing.
Now that we have some data to put under our belts, let's consider how
"unrelated" these subsequent birds are from basal Archaeopteryx. All the studies that I know of position Archaeopteryx
among the subclass Sauriurae with the earliest birds, the enantiornithines
("opposite birds") that dominated the Cretaceous. An example would be Confuciusornis from the Yixian Lagerstätte
in China, which dates from the same time as one of the earliest of the
ornithines, the still-toothed Liaoningornis. These earliest birds were quite small, and illustrate some deeper
implications for avian biology and ancestry: they could only fly by trading off
the energy their theropod cousins had devoted directly to growth, Schweitzer
& Marshall (2001, 323-325).
The Neornithes (modern) birds only proliferate in the Tertiary after the
extinction of the dinosaurs, but evidence has accumulated that primitive
versions of them go back at least into the Early Cretaceous. See Stock (1995), Feduccia (1995; 2003),
Dingus & Rowe (1998, 230-231, 235-240), Mindell et al. (1999,
147-149), Tudge (2000, 520-545), Stokstad (2001) on Norell & Clarke (2001),
Prum & Brush (2002, 269) re Zhang & Zhou (2000), and You et al.
(2006) for the progress of understanding here.
This temporal sequence (modern birds appearing only after the earlier
ones) bears on that issue of "bird lungs" that Coulter (2006, 218) jabbed at in
that bit quoted in Part II:
In
order to mutate the good stuff, like a bird's lung, there would have to be
countless mutations that were at least as better than what existed before. If each one of the incremental mutations is
more "fit" than what preceded it -- which it has to be in order to survive -- those
transitional mutations should have stayed around long enough to appear in the
fossil record, before mutating their way to something even better.
Now it would be nice if we had fossil bird lungs to inspect, but we
don't. (And does paleontologically
challenged Coulter actually think there are such things?) Lungs being soft parts, they are incredibly
unlikely to be preserved, even in the best Lagerstätte. Sometimes it is possible to draw inferences
about the otherwise invisible lung based on the associated skeleton, such as
Ruben et al. (1997) with cautions by Gibbons (1997) on the non-avian
breathing dynamics of theropod dinosaurs. But trying to inflate that into an antievolution barrier trips on the
Bermuda Triangle Defense. Just like the
spotty record for Mesozoic birds, the fossil record of early Tertiary birds
involves only a few deposits, Feduccia (1999, 166). Which means there are fewer blips on the scope to figure out what
was happening when.
But even with that caveat the record of post-Archaeopteryx birds
shows their objective retention of hollowed bones, though not as the fully
developed pneumatic "flow-through" system seen millions of years on in modern
birds. See Liem (1988, 754-755) on
avian lung and air sacs in extant birds, and Britt et al. (1998) tracing
early pneumatic openings in Archaeopteryx. As it happens, dinosaurs were especially prone to just the sort
of bone-hollowing that forms the basis for that avian "flow-through" lung
system, Lawrence M. Witmer, "Craniofacial Air Sinus Systems," and Brooks B.
Britt, "Postcranial Pneumaticity," in Currie & Padian (1997, 156-157,
590-593).
The issue of avian breathing relates not only to anatomy, but also to
the presence of an adequate thermal engine. On the theoretical side, Schweitzer & Marshall (2001) offer a
detailed sequence of evolutionary steps for theropod endothermy
(warm-bloodedness) and bird evolution, starting with some quite simple point
mutations in four bases leading to changed hemoglobin receptivity to the
"effector" proteins that trigger oxygen release. Cf. Golding & Dean (1998, 362-363) on the point mutations
that allow the hemoglobin of various bird species to extract more oxygen for
high altitude flying. By the way,
living birds have a broader thermostatic range than mammals, including
toleration for body temperatures higher than any known mammal could stand.
Because the enantiornithines are extinct, it is perfectly fair to say
they are off on a siding when it comes to the surviving modern birds. So they are "unrelated" to modern birds, but
only in the strict ancestor/descendent sense that your uncle isn't "related" to
you. As we don't use that term to apply
to uncles, or distant cousins, why should Coulter think she can get away with
such evasive ambiguity when it comes to Archaeopteryx?
The real issue about whether two taxa are related closely enough to
clarify evolutionary relationships turns on clearly defining what the
limitations of microevolutionary speciation are, as the DNA (genotype) runs
through the developmental process to produce a population of organisms
(phenotypes). No antievolutionist, least
of all Coulter, has ever been caught dead doing any of that, so the source of
Coulter's secondary ignorance is understandable, but that doesn't make the
problem go away as a scientific concern.
Buried beneath Coulter's glib paragraph is a technical taxonomical
assumption that she fails to even conceptualize, let alone investigate. What exactly does differentiate the
now-extinct Enantiornithes from later Neornithes, and does this pose that great
a problem for the Darwinian "natural selection" thing? Since you asked, the enantiornithines have a
"triosseal canal" (a slot along the coracoid bone) and the metatarsal bones of
their feet fuse in the opposite direction (proximal to distal) from that of
modern birds, Feduccia (1999, 4, 142-145). That's it.
Just how incredible is it to imagine that something like Archaeopteryx,
or any of the other enantiornithines, underwent a reduction of the triosseal
canal and reversed their metatarsal fusion process to produce the neornithines?
To answer this question, consider a hypothetical fossil "bird" showing a
reduced triosseal canal and frameshifting some regulatory genes so that the
metatarsals have reversed their fusion sequence. Shouldn't such a discovery have to be admitted as a legitimate
candidate for bird ancestor?
But we know that the dearth of Jurassic Lagerstätten means that
such a fossil might easily have escaped detection. So to clinch the scientific argument, the Design advocate might
go a few steps further, such as defining the limits within which forms are permitted
to vary (delving into coracoid genetics perhaps). Then relate that to the known fossil record (where birds
objectively show a decline in reptilian characters over time) as well as
whatever ID schema were proposed to account for that record apart from descent
with modification from some nonavian.
The result would be a chain of reasoning that would distance modern
birds from Archaeopteryx and Enantiornithes because our hypothetical
perfect ancestor could not in principle have been related to them.
I was understandably curious about whether that depth of reasoning was
part of Wells' repertoire. After all,
he might have had an encyclopedic grasp on the ins and outs of Mesozoic fauna
and the relevant developmental biology that he simply neglected to include in
his book -- aimed, like Coulter's Godless, at a general readership -- but
about which he could readily discourse if only suitably prompted.
There was one way to find out. On April 23, 2001 I wrote to Wells:
Having read your recent book, Icons of
Evolution, I am curious about the issue of how intermediate fossils are to
be identified in the fossil record, that they might provide the proper testing
of the record against either materialistic evolution or its various
alternatives.
In the case of birds, for instance, which
are believed by evolutionists to have evolved from some manner of reptile,
suppose that a perfect intermediate (or series of them) were indeed discovered
in the fossil record. What would such
forms look like in order to satisfy all sides in the debate? In what respects would a particular instance
of such an intermediate differ, say, from existing fossils like Archaeopteryx?
Here is Wells' prompt reply of April 25th, in its entirety:
I'm not sure I can adequately specify "how
intermediate fossils are to be identified in the fossil record," though Archaeopteryx
would be a very poor candidate in any case, since it lacks both the anatomical
features and the stratigraphic (i.e. chronological) position to satisfy even
those people who are determined to find intermediates between reptiles and
birds.
But even a near-perfect sequence would not
decide the issue for or against materialistic evolution, as Berra's Blunder
shows. A mere sequence of intermediates
is just as compatible with intelligent design or separate creations as it is
with materialistic descent with modification, as I point out in my chapter on
homology. What we would need in
addition to such a sequence would be a natural mechanism that produces it
without the need for intelligent intervention. The principle mechanism proposed by neo-Darwinists -- changes in genetic
programs -- doesn't fit the evidence. So
the matter remains unresolved.
A parenthetical note: Wells' reference to "Berra's Blunder" concerns Tim
Berra (1990, 118-119) who had used the gradual changes in the Corvette sports
car as a familiar way to indicate how "selection" can produce "descent with
modification" over time. Johnson (1997,
62-63) mistook this as an attempt to illustrate natural selection -- and
Pennock (1999, 260-261) subsequently turned the tables by arguing that Johnson
had indeed been tilting at a "straw man." Wells (2000, 68-70, 281) reprised Johnson's argument.
Back to the chase. To begin
with, I hadn't asked Wells to defend Archaeopteryx as a suitable intermediate. I wanted to know whether he could explain in
what way indisputable intermediates could be distinguished from Archaeopteryx. Repeating his mantra about the inadequacy of
Archaeopteryx therefore committed a fairly rudimentary error in
analytical logic. You'll notice also
that I had not stipulated a "near perfect" sequence. I had asked for his conception of conclusive
evidence. With that substitution Wells
demonstrated his agility at insulating his position rather than clarifying it.
We're back to the Olds problem. If you're claiming there are none in the junkyard, don't you have to
know what an Olds would look like? Otherwise, how would you know you weren't already looking at Oldsmobile
parts?
Before moving onto the next stage in Coulter's descent twaddle, let's
recap. Archaeopteryx is the
earliest known member of the bird group. It was part of an initial radiation of "primitive" birds that were
nonetheless very successful, dominating the Cretaceous period for tens of
millions of years. So even though
not enough fossils are known to settle exactly from which branch of
enantiornithines the modern neornithines developed (reasons for which fall
under the Bermuda Triangle Defense), it is clearly not the case that Archaeopteryx
was "just a dead end. It
transitioned to nothing."
What then of Coulter's claim that "The fossils that look like
Archaeopteryx lived millions of years after Archaeopteryx, and the
fossils that preceded Archaeopteryx look nothing at all like it"?
This statement could only have been written by someone who was not only
a paleontological ignoramus, it required somebody incapable even of digesting
their own sources. Coulter fits these
specifications spot on.
Both the "Eichstätt" specimen of Archaeopteryx discovered in 1951
and the "Solnhofen" in the 1960s were originally described as the dinosaur Compsognathus,
not only because Archaeopteryx closely resembles it, but also because
the feather impressions on those specimens were especially faint and weren't
initially spotted. Futuyma (1982, 75)
remarked on the misclassification, so this was hardly breaking news. See Wellnhofer (1990, 74-75) for skeletal
comparisons of Archaeopteryx and Compsognathus, and Briggs (1991,
136) for fleshed out illustrations.
Which information of course Wells (2000, 115) knew: "One specimen of Archaeopteryx
(collected in 1951) in which feathers were not immediately recognized was even
misidentified as Compsognathus for several years."
And thus Coulter could have known. That is, had she been an attentive reader.
Some scholarly marginalia: you may have just spotted that Wells hadn't
even got the misidentification bit right. There were two misidentified fossils, not one -- a point noted by both
of the sources Wells (2000, 295) cited: Shipman (1998, 44-45, 115) and Dingus
and Rowe (1998, 120, 138). Wells may
have been less than attentive here, though, since he gave the wrong second page
number for Dingus & Rowe ("185" instead of the correct 138).
Of course if one is like Coulter, this sort of fact spotting is never
likely to come up, is it?
And by the way, both Darwin on Trial and Icons of Evolution depended
on skipping a lot of information here, as Johnson (1991, 174) and Wells (2000,
295) had both cited Wellnhofer (1990), where the Archaeopteryx/Compsognathus
anatomical comparison was made plain. We may surmise that Dedicated Scholar Coulter did not toddle off to the
library at any stage of her "research" to check out the contents of the May
1990 issue of Scientific American listed in at least two works she had
supposedly read.
But Wells' reply to me did resolve one thing: Wells was trying to
navigate through Deep Time without anything like a working roadmap. He did this by his reminder to me about how Archaeopteryx
was in the wrong stratigraphic position to settle the issue of bird evolution.
In what possible sense could Wells have thought that claim true? Archaeopteryx predates all modern
birds, and lived long after the origin of the archosaurs from which they might
have been derived. Thus if there is one
thing about Archaeopteryx that is incontestable, it is that it is temporally
intermediate.
What Wells appeared to be doing in his letter was conflating his Icons
of Evolution argument about how specific fossil examples (from Compsognathus
to Deinonychus) might be nudged off the broad path from diapsids past Archaeopteryx
to pigeons. He was very diligent about
quoting sources to affirm that this or that taxa wasn't directly related to
this or that subsequent animal. For
example, Wells (2000, 295) asserted that Coelophysis wasn't "considered
ancestral to Archaeopteryx because, like Compsognathus, its
features are not those one would expect in an ancestor."
Of course Wells didn't explain what "features" (plural) would be
expected in an ancestor. Or whether
they would make any difference to him if such an animal were discovered.
Wells had cited two references for that claim: Carroll (1988, 290-292,
303) and Dingus & Rowe (1998, 181-183). Yet neither source had specifically excluded Coelophysis from
bird ancestry. Indeed, the page numbers
for Carroll referenced by Wells had missed the bird (ornithines) part
completely, Carroll (1988, 338-347), nabbing instead sections on theropods and
a bit on Ornithischian dinosaurs. Similar word, but no prize for Jonathan -- it's the difference between a
Triceratops and a Toucan.
In that venue, Carroll had mentioned Coelophysis briefly to
contrast its pubic bone with the similarly reverted arrangement among
Ornithischians. Wells may also have inferred
that Coelophysis was a more distant relative of birds from a chart in
Dingus & Rowe (1998, 181) that put it on a side branch of the Theropoda
node of a phylogenetic map of Aves origins.
Any fossils in that group would be fairly representative of whatever
specific taxon happened to have spawned the lineage to birds. And as you move up the phylogenetic
branches, the relevant similarities of the members of each node become more
like that of birds. That's what
cladistic analysis is supposed to do: provide empirical underpinnings for a
phylogenetic map of maximum parsimony.
Dingus & Rowe (1998, 185) specifically noted that Compsognathus
was among the basal forms of the Tetanurae, the next node up the bird
phylogenetic map from the Theropoda to which Coelophysis belonged. Consequently its features are more like that
of birds (duh, since Compsognathus and Archaeopteryx had been
literally confused more than once).
No paleontologist was saying something like Compsognathus or Coelophysis
couldn't be on the bird lineage because the maniraptorans were even closer to
the root. Cladistic analysis was only
suggesting that group to which those forms belonged lay farther back on the
line of descent than the maniraptorans. Saying that your father is your ancestor doesn't mean your grandfather
isn't your ancestor too, or that your uncle being a relative doesn't mean your
second cousin isn't a relation too.
Parenthetically, Wells' take on how cladistics informs modern
paleontology may owe a lot to Alan Feduccia, whom Wells (2000, xiii) listed
among "Those who assisted me with technical details." Gee (1999, 245n) categorized Feduccia as reflecting the
"traditional, scenario-based view of bird origins" that has been especially hard-hit
by cladistic analysis -- cf. Dodson (2000) and Sumida & Brochu (2000,
494). Although Feduccia (1999) has
accommodated somewhat to cladistics, Padian & Horner (2002) note how
Feduccia remains wedded to a "typological" way of thinking that has trouble
expanding categories to integrate new evidence. In explaining "Why Ornithologists Should Care About the Theropod
Origin of Birds" in The Auk, Prum (2002) noted how many ornithologists
were simply not acquainted with paleontological evidence and methods.
While his views have been eagerly absorbed by creationists anxious to
disconnect birds from dinosaurs, Feduccia (2002, 119) more directly parallels
antievolutionists like Johnson (1995, 12) or even Stark (2003, 177) in his
methodologically questionable assertion that critics of a theory are not obliged
to offer a comparably explicit alternative. Concerning Feduccia's reluctance to clarify his own competing bird
origin model, Prum (2003b, 551) chided: "What Feduccia rejects as the
irrational demands of phylogenetic zealots are actually the baseline requirements
of all sciences, from astrophysics to zoology."
Back to the fossils. Just how
could the Compsognathus/Archaeopteryx mix up have been possible unless
they were a lot alike?
In fact, just how alike they were should have been obvious to Wells at
least, since his own source had called attention to the ankle structure of
birds, noted by 19th century anatomists. As Dingus & Rowe (1998, 212) explained: "During growth, the 'solid'
foot of adult birds begins with all the parts that remained separate throughout
life in Compsognathus. Among
reptiles, only Compsognathus exhibited this pattern, hence dinosaurs
were the closest reptilian cousins of birds."
Here is where biologist Wells needed to switch on the inferential engine
and think biologically.
Since morphology is due to genetics, wouldn't the existence of a
dinosaur so anatomically similar to Archaeopteryx that it was repeatedly
confused for it mean that the group to which Compsognathus belonged
possessed some genes very similar to it? And was it impossible for the genetic package of that group to have been
inherited by relatives not trapped in the Solnhofen limestone, ones not
hampered by whatever it was that distinguished Compsognathus from birds?
And while we're about it -- what did distinguish Compsognathus from
birds?
Again, Wells never said. But
Carroll (1988, 340) had: "There is great overall similarity to Compsognathus,
but this genus is too late in time (as a direct contemporary of Archaeopteryx)
and too specialized in the reduction of the manus to two digits. No other adequately known theropod appears
to be an appropriate ancestor."
That was it. The Archaeopteryx
contemporary and lookalike Compsognathus lacked one finger.
As the number of digits in the vertebrate hand is modulated by alanine
repeats in the Hoxd-13 gene, the mutations required for Compsognathus
to lose that finger would appear to have been comparatively modest. Some reviews and relevant literature
pertaining to limb formation and differentiation: Goodwin (1994, 147-161), Sordino
et al. (1995), Averof & Patel (1997), Kondo et al. (1997),
Shubin et al. (1995; 1997), Gibson-Brown et al. (1998), Schwartz
(1999, 339-345), Tabin et al. (1999), Laurin et al. (2000),
Ruvinsky & Gibson-Brown (2000), Tudge (2000, 389-397), Wagner & Chiu
(2001) and Capdevila & Belmonte (2002).
Since Wells (2000, 284) cited Shubin et al. (1997) and Tabin et
al. (1999), he had to trip over some of this information too.
Given also the ubiquitous tendency for dinosaurs to reduce the number of
their fingers and toes, suggesting a genetic tendency for that existed in their
DNA, just how extraordinary would it have been for an ancestor of Compsognathus
to have had a third one, just like Archaeopteryx? Carroll was writing in 1988. Had there been any developments since to
temper Wells' quote mining in 2000? By
then a later Cretaceous relative of Compsognathus, the feathered Sinosauropteryx,
had turned up with all three fingers (more about that below). And subsequent evaluation of the original Compsognathus
(it is known from only two specimens, incidentally, one from France and the
other in the Solnhofen) suggests it may have had the third digit too, but that
this had simply been overlooked in its current fragmentary state (see
http://www.dinosauricon.com/genera/compsognathus.html).
Since neither the detailed paleontology nor the developmental angle ever
arose in Wells' book, he didn't have to think about these things. But then, given his letter to me, would it
have changed his mind if Compsognathus had had three fingers? You get three guesses.
Following just how much of the forensic information got missed by Wells,
it is easier to see how Wells (2000, 123) could write: "The claim that birds
are dinosaurs strikes most people -- including many biologists -- as rather strange. Although it follows from cladistic theory,
it defies common sense. Birds and
dinosaurs may be similar in some respects, but they are also very different."
And exactly what survey of biologists did Wells conduct to indicate just
how "many" questioned the dinosaur origin of birds, or on what basis they
supposedly did it? Nor did Wells
clarify just what these "very different" features consisted of that underlay
his populist "common sense" take on dinosaurs.
Imagining secondary Coulter reading this -- and never investigating the
veracity of what she has read -- makes Coulter's confusion regarding what animals
existed in the past far easier to understand (though once more, not
condonable). This incestuous
concordance of Coulter and Wells hit bottom when it came to the significance
(and temporal existence) of maniraptoran theropods like Deinonychus that
are believed to represent the closest dinosaur relatives of birds. Here's what Wells (2000, 121) had written:
Ironically, once cladistics took over and
similarity became the only criterion for relationships, paleontologists
found that the most likely candidates for the ancestor of Archaeopteryx
lived tens of millions of years later. It was no longer its contemporaneity with Archaeopteryx that
ruled out Compsognathus as an ancestor, but the fact that it didn't have
the right features. According to the
cladists, the animals with the right features were bird-like dinosaurs that
lived in the Cretaceous period, long after Archaeopteryx had become
extinct. But then, in order to make
bird-like dinosaurs the ancestors of birds, the fossil evidence must be
re-arranged. (Figure 6-2)
That "Figure 6-2" was where Wells mentioned (but did not discuss) the
extinct Cretaceous birds, by the way. With that, everything about this passage was absurdly confused and
inaccurate.
We'll skip over whether Wells was proposing that relationships be
founded on dissimilarity. Instead, we have to wonder what Wells was thinking about relationships.
Given the fact that all known Archaeopteryx fossils come from a
single deposit, we have to wonder how Wells (or Coulter secondarily) has
divined when they went extinct. They
have to have gone by the wayside before the present, and if they were average
they probably fizzled out after a few million years (as virtually every species
has). For example, Fastovsky &
Weishampel (1996, 361-364, 367, 369, 370-372, 375, 379) catalog the fossil
sites relevant to the appearance and evolution of dinosaurs, noting the typical
genus (that is the taxonomical rung above species, one should recall) appears
to persist for 4-8 million years.
But if Wells is going to switch on that side of the inferential engine,
he had better not forget the other side. When did Archaeopteryx first appear?
That too we can't know, since we only have the one Solnhofen slice.
But these questions apply just as readily to the maniraptorans. We know Deinonychus existed in the
Early Cretaceous. But when did it appear? As Wells' own source of Dingus and Rowe
reminded, the theropod record is poor. But it's not entirely absent. Those same authors had specifically noted a femur that indicated
"nonflying maniraptorans" were living in the Jurassic, Dingus & Rowe
(1998, 213). See Kevin Padian &
Luis M. Chiappe, "Bird Origins," Brooks B. Britt & Brian D. Curtice, "Dry
Mesa Quarry," Philip J. Currie, "Theropoda," and David J. Varricchio,
"Troodontidae," in Currie & Padian (1997, 78, 196, 734, 750) on that, as
well as dromaeosaurid and troodontid teeth from the Late Jurassic. Cf. Dodson (2000, 506, 509).
What has confused Wells along with all of the antievolutionists in this
area (including secondary addict Coulter) is something that should be obvious
to anyone operating with a working map of Deep Time. The Cretaceous maniraptorans get highlighted because those are
the fossils that have been found comparatively complete. That's true for most of the Mesozoic, where
the bulk of the taxa date from the Cretaceous because that's where the deposits
are. It's the Bermuda Triangle Defense
again.
But paleontology marches on, and the maniraptorans get pushed farther
back with each new discovery.
In 2002 a basal troodontid (Sinovenator) turned up from the Early
Cretaceous, whittling down that gap with Archaeopteryx to about 25
million years (still a long time). But
even before Icons of Evolution appeared, a fragmentary therizinosaurid
coelurosaur (DEMBSKI ALERT) was found from the Early Jurassic (50 million years
before Archaeopteryx) -- and at least one Cretaceous therizinosaur has been
found with proto-feather integuments. See Xu et al. (2002) on Sinovenator, Zhou & Xu (1998)
and Xu et al. (1999a) on the therizinosaurids, and Prum & Brush
(2002, 278-279) on the framework of bird ancestry.
Which brings us to feathers.
The recent discovery of feathered theropods has driven a huge hole into
the argument that birds popped out of nowhere. To discover that the most distinctive feature of birds show up in the
one group regarded on cladistic grounds to be most like that of birds in other
ways strains the load limit of the "I don't want to think about such things"
mindset of antievolutionists like Wells or Coulter.
To be fair, Coulter probably doesn't know there are feathered
dinosaurs. And that's because Wells
(2000, 123-130) went out of his way to dismiss them. Like Coulter (2006, 235), Wells (2000, 213-126) trumpeted the
Archaeoraptor hoax (where a Chinese fossil merchant had sold a spliced together
dino-bird that ended up highlighted by National Geographic). See Sloan (1999) with the Simons (2000)
autopsy. Coulter even called it the
Piltdown Bird, exactly as Wells had. Ironically, it turns out that both parts of the chimera were
paleontologically interesting. Zhou et
al. (2002) investigated the bird part. But it was the dromeosaurid tail segment that turned out to be the most
exciting. It turned out to be from a Microraptor,
a small (possibly arboreal) dromeosaurid that had feathers on the tail and
both front and hind limbs, Stokstad (2000; 2003), Prum (2003a) re Xu et
al. (2003), and Padian (2003).
While the Microraptor specimens surveyed by Xu et al.
reopen the theoretical possibility that protobirds could have had an arboreal
stage, it more obviously indicates how varied feathered theropods could get
(just as in mammals there are "flying" squirrels as well as fully aerial
bats). Of relevance to the
arboreal/cursorial flight debate is the recent experimental support for the
behavioral and aerodynamic viability of the cursorial approach to general bird
flight, Pennisi (2003) re Dial (2003).
And it should be noted that this information on Microraptor
predates Coulter's current book by three years. So why didn't it come up in her reference to Archaeoraptor? That's a no-brainer: Coulter is a
"no-brainer" -- and a lazy one at that.
Now the "discussion" of feathered theropods in Icons of Evolution
consisted of Wells (2000, 126-130, 298-299) castigating reconstructions or
depictions of dinosaurs with feathers -- not an evaluation of the actual
dinosaur fossils that had by then had been discovered with feathers on
them. For Wells (and thus Coulter) out
of sight is evidently out of mind.
The realization that birds and dinosaurs were very closely related had
long snagged on the issue of feathers. Where had birds got them? They
were such specialized features that the odds were that they appeared only once,
not evolved convergently in many independent lineages.
But even had feathered ancestors lived, their successful preservation
was a long shot. As Chris McGowan had
noted back in the 1980s (and the fossil record of Archaeopteryx
continued to demonstrate), a feathered fossil was only likely to be preserved
in the rarest of Lagerstätten circumstances. It was no coincidence then that the spectacular new Spanish
Cretaceous birds were turning up in lithographic limestone, just as Archaeopteryx
had in the Solnhofen. This was also the
case for the finds coming from China.
Ah, but evolutionists have that silent partner oddly committed to coming
through for them in a pinch. Evidently
feeling in an especially puckish mood back in the Mesozoic, and without
consulting Jonathan Wells, the Designer decided what paleontologists really
needed to perk up their day late in the 20th century were a few impressively
feathered dinosaurs. So he planted some
appropriately bird-sized ones in China, in triplicate, Phillip J. Currie,
"'Feathered' Dinosaurs," in Currie & Padian (1997, 241), Unwin (1998) re
Chen et al. (1998), Ackerman (1998) and Padian & Chiappe (1998,
44-45). Oh yes, let's not forget
Shipman (1998, 274-277) -- that cited source available to Wells.
In any case, these new fossils were just what Darwinists had in
mind. The three-fingered Sinosauropteryx
again resembled the "usual suspect," our old friend Compsognathus -- only
this time covered with rudimentary feathers, short "downy filaments" with a
central rachis and wildly fraying barbs. The other two were similarly transitional. Although the forelimbs of Protarchaeopteryx and Caudipteryx
were not adapted for flying, they were nonetheless fully feathered with non-aerodynamic
plumage, including symmetrical ones bearing the more familiar rachis-shafted
configuration. Indeed, they looked
surprisingly like the "hypothetical pre-bird" illustrations of John Ostrom, the
ones Gary Parker offered in Morris & Parker (1987, 139) or Hanegraaff
(1998, 38-39) secondarily as examples of how evolutionists founded their
conceptions on "faith, not facts." Cf. Caudipteryx
and Sinosauropteryx shown in Ackerman (1998, 74-75, 82-83).
The snap reaction of opponents of the dinosaur/bird theory was to doubt
the features were related to feathers, noted by Horgan (1997, 22) and Shipman
(1998, 276-277), and expounded since by Feduccia (1999, 132, 375-378, 394-398),
Geist & Feduccia (2000, 668), Martin & Czerkas (2000, 690-691) and Ruben
& Jones (2000, 592-593). Steve
Czerkas, by the way, was one of those who had been caught napping in the
Archaeoraptor case -- some irony here.
But a third Caudipteryx specimen has tipped the scales in favor
of the theropod view, Normile (2000). And additional "integumented" Chinese theropods have turned up in the
Jurassic/Cretaceous boundary (125-147 Mya) to render the "fluke" model of
feathered theropods moot: Xu et al. (1999a,b; 2001), Norell (2001), Sues
(2001) on Ji et al. (2001), and Norell et al. (2002). See Prum & Brush (2002, 276-280; 2003)
for an overview of the current evidence.
All this has provoked some interesting exchanges. For example, Prum (2003b, 553-554) wryly
noted how Feduccia (2002, 1196) had gone from arguing that dromaeosaurs were
unrelated to birds to claiming now that they were actually feathered flightless
birds that only convergently resembled dinosaurs!
At the same time as these feathered theropods were turning up, relevant
evidence has come in from another direction: the developmental biology of
feathers.
It had long been recognized that there was a connection between feathers
and reptilian scales. Scales, feathers,
and even mammalian hair are made of keratin, Brush (2000, 635), Maderson &
Alibardi (2000), Stettenheim (2000, 465-466, 469) and Prum & Brush (2002,
290). The basic α-keratin composing mammalian hair also
appears in the reticulate scales of birds and the outer sheath of their feather
buds. 90% of feathers consist of the
modified β-keratin, also expressed generally in reptile
and avian epidermal cells, the beak covering (rhamphotheca) and claws, as well
as their scutellate leg scales. The
specialized form of β-keratin in
feathers (f-keratin) differs slightly in having a
repeated tripeptide. See Molloy et
al. (1982), Koltunow et al. (1986), Presland et al. (1989)
and Whitbread et al. (1991) on relevant keratin genes and their
expression -- with Gregg et al. (1984) suggesting "feather-like keratin
genes may have evolved from a scale keratin gene by a single deletion event."
Structurally, feathers are essentially frayed scales. Just how closely feathers and "scales" are
related has also been noted by French paleontologist Philippe Taquet (1994,
197): "This is so true that if you inject retinoic acid under the skin of the
feet on chicken embryos, they'll grow feathers there where normally there are
scales." For the technically minded,
Zou & Niswander (1996), Crowe & Niswander (1998) and Widelitz et al.
(2000) examine the signaling paths that transform scutellae into feather filaments
and buds. For meringue, Menon &
Menon (2000, 551) recently noted that "retinoids are increasingly being
implicated in morphogenesis, homeobox gene transcription, etc."
It should be noted -- again not much of a surprise here -- that few
creationists pay the slightest attention to the keratin matter. Wieland (1988; 1994) veered closest, but
other creationist and design authors have shown no curiosity here. That would include our consistently
somnolent Wells and Coulter.
In the "look who's actually doing the hard work" department, it was
research into the developmental biology of feathers that has provided yet
another line of evidence pointing straight at the feathered theropods. Starting independently, and more recently
teaming up, Alan Brush and Richard Prum worked out the only way feathers could
have evolved consistent with the mechanics of feather construction. Isolating the developmental differences
between tubular feathers and flat scales, their work has affirmed the homology
of scales and feathers at the deeper developmental level of the placode ("an
epidermal thickening above a condensation of dermal cells").
Thus Brush (2000, 633) concluded feathers developed from
filament-forming "tubercule-like" features (similar to those seen in dinosaurs
and living reptiles) rather than directly from a specifically "flat
Archosaurian scale." And when the
feathered theropods started showing up, Prum & Brush (2003) couldn't avoid
noticing that those curious "integumentary structures" were just like the
protofeathers they had deduced from their study of feather development.
Once again, had Coulter a running subscription to Scientific American
she might have stumbled onto this. But
could she have understood any of it even if she had? Someone who has no familiarity with (or apparently curiosity
about) developmental biology, genetics, taxonomy (fossil or living) or
paleontology?
Only Coulter will be able to clarify that. But we can say, categorically, she doesn't discuss it. Hence one more reason to conclude that Coulter's
remarks on bird evolution are utterly worthless.
You may have noticed something about this posting, which should be no
surprise for those who are familiar with creationist apologetics. It took many pages to explain why Coulter's
single paragraph was wrong. That is one
of the daunting challenges facing all who take on the Coulters of the world (or
Hovinds ... or even the Discovery Institute pooh bahs). Ignorance and ideology are high compression
pursuits, prone to scattershot and rhetorical excess, whereas genuine science
is "slow down to thinking speed" and make sure all your facts are lined up
properly.
This conflict inevitably leads to cross talking (witness my exchange at
Dembski's Uncommon Descent) but such is life.
Part
IV coming attractions ... Coulter vacations in the Cambrian, and explodes.
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See also
The DEMBSKI ALERT
Secondary Addiction: Ann Coulter on Evolution
Secondary Addiction Part II: Ann Coulter on Evolution
Discussion
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