On Wed, 15 Nov 95 13:36:21 MST you wrote:
>
>On Mon, 13 Nov 95 23:16:44 EST, sjones@iinet.net.au (Stephen
>Jones) said:
>
>---------------------------------------------------------
SJ>"It's the early bird that fits the bill"
>
>BIRDS with modern-looking beaks appeared on the evolutionary scene
>much earlier than palaeontologists had thought. Beaks were not
>supposed to have evolved until 75 million years after Archaeopteryx,
>the earliest known bird. Now researchers say that some avian species
>had evolved proper beaks just a few million years after Archaeopteryx
>made its debut.
>
>In this week's issue of Nature (vol 377, p 616), Lian-hai Hou and
>Zhonghe Zhou of the Institute of Vertebrate Palaeontology and
>Palaeoanthropology in Beijing and their colleagues describe three
>partial skeletons of a bird they call Confuciusornis. The fossils
>come from ancient lake sediments near China's border with Korea.
>These deposits are difficult to date accurately, but the researchers
>believe that Confuciusornis lived about 10 million years after
>Archaeopteryx, which appeared around 145 million years ago.
[...]
JF>It's worth noting that Martin *may* have a bias towards evidence
>that would indicate an older (than mid-Jurassic) age for birds. He
>is well known as one of the hold-outs against the idea of a
>dinosaurian origin for birds. (I think he is in favor of a more
>crocodilian-type ancestor for birds; yes, I know that sounds silly;
>no, I don't agree with it)
Thanks for this background. But why is believing that birds did not
evolve from dinosaurs necessarily "bias"? He might be right and all
the others biased! :-)
SJ>(Peter Aldhous, "It's the early bird that fits the bill", New
>Scientist, 21 October 1995, p19)
>---------------------------------------------------------
SJ>If birds with beaks existed "just a few million years after
>Archaeopteryx made its debut", then if evolutionists wish to maintain
>that Archaeopteryx is a transitional form between reptiles and birds,
>it seems they must postulate either: a) a very rapid transformation
>of teeth into a beak; or b) assume that Archaeopteryx dates from
>further back in the fossil record.
JF>The "few million years" is really 10 million years, which seems to
>be to be ample time to evolve a beak. Having the teeth disappear
>seems pretty easy, developing a beak sounds a bit more difficult,
>although I know nothing about beaks. Embryology may tell scientists
>how beaks develop, but I'll have a guess and say that it may have
>evolved from keratin, just like our fingernails or a rhino's horn.
The article also says "Now researchers say that some avian species
had evolved proper beaks just a few million years after Archaeopteryx
made its debut" and that "Beaks were not supposed to have evolved
until 75 million years after Archaeopteryx".
I do not rule out that God may have built birds from a reptilian
body-plan. What I am sceptical of is the Darwinian "just-so" stories
that explain why and how it happened. I would like to see a tightly
reasoned scenario which shows how in between 3 -10 million years a
bird with teeth could: a) lose them; and b) gain a beak, using only
the Darwinian blind watchmaker mechanism of mutation plus natural
selection. The changes here seem massive and it is difficult to
imagine a fully functional series of transitional forms each being
more selectively advantageous than the previous, between a bird with
a jaw and teeth and one with a beak and no teeth.
SJ>The problem for evolution with a) is finding a naturalistic
>evolutionary mechanism that can transform a full set of teeth into a
>beak in "just a few million years". OTOH, the problem with b) is it
>might push Archaeopteryx back too far before its putative dinosaur
>ancestors, and to where there is no fossil evidence. Of course if it
>is supposed that Archaeopteryx existed much earlier than the fossil
>record indicates, then one could claim the same for Confuciusornis!
JF>Although Archaeopteryx is considered a superb example of a
>reptile-bird intermediate, I have heard claims that it is *not*
>considered to be a direct ancestor of all later birds (I do not know
>why). Archae and this new find could have a somewhat older common
>ancestor.
I understand, that: a) it is contemporaneous with its putative
ancestors and b) it is too specialised.
SJ>Also, if an "advanced characteristic" such as a beak, was naturally
>selected because it had survival value, then "subsequently died out"
>(presumably because it had lost survival value), it strains
>credibility and believe the same feature was again re-selected
>because once more it had survival value!
JF>This is an over-simplification of evolutionary theory. Assuming
>the beak evolved for some survival value, the later extinction of
>some branches doesn't tell us anything about the beak; it could have
>happened for many other reasons (e.g. disappearing food source).
That is not what the article says:
"The new discovery suggests that the features we associate with modern
birds have probably evolved and disappeared several times, says
Martin. Some advanced characteristics, such as true bills, evolved
early on in groups that subsequently died out."
SJ>Please note that as a Progressive Creationist, I do not necessarily
>deny that the bird archetype is a variation on a reptilian theme, but
>I am sceptical that a plausible naturalistic evolutionary mechanism
>could produce the result in the shortening time available.
JF>Hang on, we're talking *10 million years*, almost twice the time it
>is thought to have taken humans to evolve from apes. Evolving a beak
>seems a trivial change, compared to that. Our sampling density (two
>species, in tens of millions of years) can hardly be expected to give
>us a good handle on the fine details of the evolution of birds.
No. We may be talking only of "just a few million years after
Archaeopteryx made its debut" of a trait that previously was thought
to have taken "75 million years after Archaeopteryx".
JF>This new find sounds like strong support for evolution, not
>evidence against it. We've got a new bird, a bit younger and a bit
>more modern looking than the oldest known bird.
Everything is always claimed by evolutionists as "strong support for
evolution"! :-) My general argument is that the shorter the
time-frame,
the more likely it was a result of Divine intervention.
God bless.
Stephen
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