(cut off the first bit of this quote, sorry) the bipedality and bird- like
appearance of Iguanodon were entirely vindicated by the discovery of
complete skeletons of Iguanodon at Bernissart in Belgium...The
general proportions of the body of this dinosaur are amazingly
similar to those of a kangaroo, confirming Leidy's interpretation.
On the other hand, when looked at in detail the feet and legs are
extremely bird-like in shape; and - most importantly - the bones of
the hips are arranged very much like those of birds (for this is an
ornithischian or "bird-hipped" dinosaur) confirming Huxley's views as
well." (Norman D., "Dinosaur!", Boxtree: London, 1991, p93)
The real truth is Darwinists do not know which dinosaur group
birds came from. This is admitted by Norman:
"Take your pick. Any final judgment on the matter is based on
personal preference for particular idea or theory. Several groups of
workers have pointed out problems with Ostrom's views concerning the
closeness of the relationship between dinosaurs and birds. Fine
points in the anatomy of the ear in birds and crocodiles have been
put forward as persuasive evidence that the ancestry of birds has to
be put back into the Triassic - supporting the views of Alick Walker.
Yet others favour an archosaur ancestry of birds because of fine
differences seen in the structure of the shoulder, wrist and pelvis.
In addition to the work of Professor Ostrom, detailed studies of the
anatomy of theropods as a whole by Dr Jacques Gauthier of the
California Academy of Sciences have pointed to a very strong
similarity between Deinonychus and its relatives (the
deinonychosaurs, or dromaeosaurs as the group is sometimes called)
and Archaeopteryx. At the present time the majority of dinosaur
paleontologists (myself included) favor a shared ancestry for
theropod dinosaurs and birds probably in the Early Jurassic Period,
and therefore support Ostrom's conclusions." (Norman D.,
"Dinosaur!", Boxtree: London, 1991, p199)"
I don't know how relevant Huxley is to all of this...he didn't have all
of the evidence we do. It is true that the bird-hipped dinosaurs have hips and
sometimes other traits that are somewhat birdlike (especially earlier ones; by
the Cretaceous, most "bird-hipped" dinos had hips that didn't look much like
bird hips (National Geographic, Jan 93, p. 200). The point is that animals are
classified by a large number of traits that are shared by a large number of
animals and that are displayed no matter what ecological role the creature
plays. This is the key to overcoming the problems of convergence. One, or
several, traits may converge, but traits that are RESISTANT to change due to
adaption to ecological roles are best for determining kinship. I agree that we
could classify animals into those with flippers, wings, feet, etc; but we would
be lumping together animals with many contrasting traits for each one that is
the same. Molecular traits are the ultimate in resistance to change due to
adaptation: many mutations in DNA are not expressed at all, so any similarity
between the DNA sequences in two species cannot be due to convergence from
evolutionary pressure. The similarity must be due to luck (extremely unlikely)
or kinship. The fact that molecular evidence independantly correlates
conclusions drawn from physical nonadaptive traits in almost all cases (Dawkins
porcupines may be a noteworthy exception where DNA sequencing is forcing
revision of old views) is encourages me that taxonomists, for the most part,
have been doing it right, for the most part, for most of the time (which is
really all that you can ask of a scientist).
"I agree that "this dinosaur is also displaying bird-like traits" ie.
it has a beak. But so does an octupus."
See above - an octopus shares none of the "dozen skeletal characteristics"
(Jan. 93 National Geographic, p. 8) that identify dinosaurs, while I bet that
birds share a number of them.
"And as for "lizard hips", I cannot see that is "evidence of kinship"
of dinosaurs and birds."
I said this too fast, sorry. Some dinos in the "lizard-hipped" catagory have
hips and other skeletal traits that look a lot like bird skeletal
characteristics, enough so that Archeopteryx was been misidentified as a
"lizard-hipped" dinosaur instead of a bird in case where the feathers were
poorly preserved.
"My other points was that: a) there was nothing new about
Ornithomimus having a beak; and b) it is too recent to be ancestral
to birds. To the extent that this is not told to the general reading
public, it is "propaganda"."
I guess you're right. Maybe what was "new" was that the Ornithomimus discovered
was "perfectly preserved", leaving it beyond question that it was a birdlike
dino with a beak. Perfect skeletons are very, very rare - until recently, the
most famous dino, T-rex, was only known from 3 complete skeletons. On b), I
wholeheartedly admit that this dino is not ancestral to birds. The fault, I am
certain, lies with the press (which condenses everything into soundbites), and
not with the paleontologist, who would know this. However, the article does
not SAY that Ornithomimus was ancestral to birds: it says that Ornithomimus
(whether completely new or not, I don't know) is evidence that birds descended
from DINOSAURS. I'll repeat, for emphasis, since this is just about the most
common mistake I see in understanding evolution: FOSSILS CAN BE EVIDENCE OF
DESCENT OF ONE GROUP FROM ANOTHER WITHOUT THEMSELVES BEING DIRECT ANCESTORS OF
THAT GROUP. Sorry to shout, but if this was better understood (and if the
press mentioned it specifically in news articles, like they should have in this
one), then a whole lot of arguments between pro and anti evolutionists would go
away. Do you agree with this, Stephen?
A quick example or two to illustrate: a platypus, an egg-laying mammal
(monotreme) is an evidence of mammals' descent from reptiles. The platypus has
many other traits intermediate between reptile and mammal (partially
warm-blooded, etc). Thus, the platypus descended from a reptile-like mammal,
and the reptile-like mammal descended from, obviously, reptiles. Humans, bats,
whales, cows and other placental mammals don't share many traits with reptiles,
but the fact that there is a mammal that does share those traits lets us
conclude that they are descended from a reptile-like mammal also. Note that I
did NOT say that all placental mammals are descended from platypus's/platypus'
(platypi??). Placentals and monotremes share a common ancestor.
This is evolution 101, but it is often missed. Denton's book (which
you like to quote so much - he does make some valid points) makes this mistake
by saying that because molecular evidence shows that, say, monotremes and
placentals are equally different from reptiles, this means that placentals
cannot have evolved from monotremes, as theory states. He thinks monotremes
should be intermediate between reptiles and placentals for the theory to be
correct. His mistake is in thinking that TODAY'S monotremes should be
intermediate, while actually the theory says that reptile-like mammals existing
in the Triassic are the ones that should be intermediate. Today's monotremes
have had just as much time as everyone else to diverge from their reptile
ancestors.
"NM>That said, I agreed with much of the rest of what Jones said: the
>story about the creature's death seems far fetched, and convergent
>evolution is a problem (though not an unsolvable one, as the current
>example shows).
Thanks for agreeing that the story about the dinosaur's death seems
"far fetched"."
No problem; I don't think that telling that little story hurts much as long as
everyone realizes it is a story and not a theory. It is a likely explanation,
but it is just as possible that the little guy fell, broke his leg, but died
from a disease a day or two later.
"But I cannot see how "the current example shows" that "convergent
evolution is a problem (though not an unsolvable one...). Without
access to the soft anatomy or molecular biology of dinosaurs, I
cannot see how Darwinists can be sure that the similarities between
reptiles and birds are not just convergence. Denton:
"To demonstrate that the great divisions of nature were really
bridged by transitional forms in the past, it is not sufficient to
find in the fossil record one or two types of organisms of doubtful
affinity which might be placed on skeletal grounds in a relatively
intermediate position between other groups. The systematic status
and biological affinity of a fossil organism is far more difficult to
establish than in the case of a living form, and can never be
established with any degree of certainty. To begin with, ninety-nine
per cent of the biology of any organism resides in its soft anatomy,
which is inaccessible in a fossil. Supposing, for example, that all
marsupials were extinct and the whole group was known only by
skeletal remains would anyone guess that their reproductive biology
was so utterly different from that of placental mammals and in some
ways even more complex?" (Denton M., "Evolution: A Theory in
Crisis", Burnett Books: London, 1985, p177)
Indeed, as to "the problem of convergence", Denton points out:
"Nature abounds in examples of convergence: the similarity in
overall shape of whales, ichthyosaurs and fishes, the similarity in
the bone structure of the flippers of a whale and an ichthyosaur, the
similarity of the forelimbs of a mole and those of the insect, the
molecricket; the great similarity in the design of the eye in
vertebrates and cephalopods and the profound parallelism between the
cochlea in birds and mammals. In all the above cases the
similarities, although very striking, do not imply any close
biological relationship." (Denton M., "Evolution: A Theory in
Crisis",1985, Burnett Books, p178) "
I agree that working simply from bones is harder than from whole organisms, but
we can acheive some certainty, at least, because there are skeletal traits not
linked or not strongly linked to adaptation that will exist whether or not the
creature walks, flies, or swims. While a paleontologist could not divine the
marsupial's reproductive system from it's fossils, I'm sure they could tell you
that what they were looking at was not any common mammal. If no marsupials
were alive today, we would still know that an ancient, extinct branch of
mammals existed - based soley on fossil evidence.
"The bottom line is that animals are more like each other than plants,
and birds are clearly like reptiles in some respects and markedly
different in others. Indeed, even if reptiles and birds have a
common genetic ancestry, that is not necessarily conclusive evidence
of fully naturalistic evolution. One would still have to show:
1. *how* a bird evolved by 100% naturalistic mechanisms from a
reptile, as Darwin clearly saw:
"In considering the Origin of Species, it is quite conceivable that a
naturalist, reflecting on the mutual affinities of organic beings, on
their embryological relations, their geographical distribution,
geological succession, and other such facts, might come to the
conclusion that species had not been independently created, but had
descended, like varieties, from other species. Nevertheless, such a
conclusion, even if well founded, would be unsatisfactory, until it
could be shown how the innumerable species inhabiting this world have
been modified, so as to acquire that perfection of structure and
coadaptation which justly excites our admiration." (Darwin C., "The
Origin of Species", 6th edition 1872, Everyman's Library, J.M. Dent
& Sons Ltd: London, 1967, p18).
2. fossil evidence of the numerous transitional steps required by
Neo-Darwinian theory to transform step-by-step by tiny increments a
reptile into a bird:
"Let us hear the conclusion of the whole matter. The essence of life
is statistical improbability on a colossal scale. Whatever is the
explanation for life, therefore, it cannot be chance....Cumulative
selection, by slow and gradual degrees, is the explanation, the only
workable explanation that has ever been proposed, for the existence
of life's complex design....To 'tame' chance means to break down the
very improbable into less improbable small components arranged in
series. No matter how improbable it is that an X could have arisen
from a Y in a single step, it is always possible to conceive of a
series of infinitesimally graded intermediates between them. However
improbable a large-scale change may be, smaller changes are less
improbable. And provided we postulate a sufficiently large series of
sufficiently finely graded intermediates, we shall be able to derive
anything from anything else, without invoking astronomical
improbabilities." (Dawkins R., "The Blind Watchmaker", Penguin:
London, 1991, p317-318)"
I agree that with birds, we need a lot more evidence, but, as this
entire post shows, we have a good guess (can't ask for much more than that with
science). Denton assumes that all we have is:
reptiles--->birds
while what the theory is (as supported by fossils so far - there are many gaps)
is:
reptiles--->Eoraptor or similar primitive "lizard-hipped dinosaur"
--->theropods--->
Archeopteryx or similar dino-like bird ---> Sinoris (early bird from Cretaceous)
or similar bird ---> Cenozoic birds.
Other evidence that supports this are more distant offshoots of the bird line:
Ornithiscians, Cretaceous toothed waterbirds, dinos with bird-like breastbones.
It is still very sketchy, but it is a little closer to the standards of proof
you want. Since the world isn't perfect, we're never going to completely
"proove" anything - but the evidence is piling up in one direction, and
imagining another theory will become more difficult if the trend continues.
"Neo-Darwinian evolution may be the best naturalistic theory that
explains the similarity of birds and reptiles, but that does not
means it is correct:
"The same situation looks quite different to people who accept the
possibility of a creator outside the natural order. To such people,
the peppered-moth observations and similar evidence seem absurdly
inadequate to prove that natural selection can make a wing, an eye,
or a brain. From their more skeptical perspective, the consistent
pattern in the fossil record of sudden appearance followed by stasis
tends to prove that there is something wrong with Darwinism, not that
there is something wrong with the fossil record. The absence of
proof "when measured on an absolute scale" is unimportant to a
thoroughgoing naturalist, who feels that science is doing well enough
if it has a plausible explanation that maintains the naturalistic
worldview. The same absence of proof is highly significant to any
person who thinks it possible that there are more things in heaven
and earth than are dreamt of in naturalistic philosophy. Victory in
the creation-evolution dispute therefore belongs to the party with
the cultural authority to establish the ground rules that govern the
discourse. If creation is admitted as a serious possibility,
Darwinism cannot win, and if it is excluded a priori Darwinism cannot
lose." (Johnson P.E. "Evolution as Dogma: The Establishment of
Naturalism", Foundation for Thought and Ethics, 1990, p8)
God bless.
Steve"
I'm too exhausted to respond to this in full (I might rouse myself in the
future), but I would like to point out the similarity between this view of
Johnson's (a good-ol' upstanding conservative) and that of cultural relativists
who are so far left that...well, I don't know what. According to them, reality
is nothing more than what is dictated by the people in charge. Johnson uses
this weapon against science, saying that it is simply the prevailing authority,
no more correct than anyone else. However, cultural relativism will tell you
that this applies to ANY prevailing authority, and that any group's view is
true within that group. Of course, this applies to the religion believed by
everyone on this listserv, and to basically any belief in anything. Basically,
reality is someone agreeing with you. If anyone believes Johnson's quote, then
you believe this, too.
See ya,
Nick
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| Stephen E (Steve) Jones ,--_|\ sejones@ibm.net |
| 3 Hawker Avenue / Oz \ sjones@iinet.net.au |
| Warwick 6024 ->*_,--\_/ http://www.iinet.net.au/~sjones |
| Perth, West Australia v (My opinions, not my employer's) |
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