A successful prediction of evolutionary theory: Tiktaalik
pnyikos
claim that this and that discovery was "predicted by evolutionary
theory," but even I cannot deny the appropriateness of applying that
to the discovery of *Tiktaalik*, a transitional form between lobefin
fish and tetrapods of the Devonian.
The transitional status of *Tiktaalik* was brilliantly explained by
Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
_Nature_:
http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
Since this article may not be available without some sort of
subscription or payment of fee, I will be quoting quite a bit from it
on this thread. In brief: there are lots of characters in the skull
(especially the region of the ear) and fins that are intermediate
between that of *Panderichthys*, another transitional lobefin, and
such primitive tetrapods as *Acanthostega* and *Ichthyostega*. You
can read a bit about them in the following site, which is available
free of charge:
http://chronicle.uchicago.edu/081023/tiktaalik.shtml
But now, on to why I call this discovery a prediction of evolutionary
theory. The following quote from another good website (also available
free of charge) on *Tiktaalik* explains that part:
_____________ begin excerpt
Tiktaalik is important, well-preserved, and certainly newsworthy � but
it was not unforeseen. The paleontologists who found Tiktaalik went
looking for it. Previous research suggested that vertebrates' invasion
of land took place about 375 million years ago in a river � so Shubin
and fellow researchers searched for fossils in 375 million year old
rocks that had preserved a river delta ecosystem. Having studied other
organisms from this water/land transition, the paleontologists knew
what sort of animal they were looking for. And when they did discover
Tiktaalik (after five separate expeditions to Canada), it wasn't much
of a surprise: Tiktaalik had the set of characteristics that they had
expected to find in such an organism. In sum, discovering Tiktaalik
simply confirmed many of the hypotheses biologists had held for a long
time regarding the origin of terrestrial vertebrates.
============ end of excerpt from
http://evolution.berkeley.edu/evolibrary/news/060501_tiktaalik
Don't lay too much store by that "In sum" bit--it's the kind of
statement I've often criticized as too general to be adequate. It is
the part that came before that delivers the goods. One does not go on
such exorbitantly expensive expeditions to remote places unless the
places were carefully picked on the basis of implicit predictions.
You see, it wasn't some easily accessible place in Canada to which
they went. It was to Ellesmere Island in Nunavut, Arctic Canada.
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://www.math.sc.edu/~nyikos/
nyikos @ math.sc.edu
pnyikos
> The transitional status of *Tiktaalik* was brilliantly explained by
> Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> _Nature_:
>
> http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
This "News and Views" article compares *Tiktaalik* with a slightly
earlier (by ca. 2 mya) transitional form, *Panderichthys*, on the one
hand, and a later primitive tetrapod, *Acanthostega* on the other.
About the former, the authors write [citations omitted]:
"Panderichthys* is vaguely crocodile-shaped and, unlike the rather
conventional osteolepiform fishes farther down the tree, looks like a
fish–tetrapod transitional form. The shape of the pectoral fin
skeleton and shoulder girdle are intermediate between those of
osteolepiforms and tetrapods, suggesting that *Panderichthys* was
beginning to 'walk', but perhaps in shallow water rather than on
land."
By the way, osteolopiform fishes have been "rehabilitated" by the
authors as transitional between still earlier lobefins and tetrapods
in:
http://www.biology.ualberta.ca/courses.hp/biol606/papers/Ahlberg+1998.pdf
Now, on to the next quote from their _Nature_ article:
" *Panderichthys* lived about 385 million years ago at the end of the
Middle Devonian; *Ichthyostega* and *Acanthostega* lived about 365
million years ago during the Late Devonian. However, the earliest
fragmentary tetrapods from Scotland and Latvia date back to perhaps
376 million years ago, so the morphological gap between fish and
tetrapod corresponds to a time gap of under 10 million years.
"Into this gap drops *Tiktaalik*. The fossils are earliest Late
Devonian in age, making them at most 2 million or 3 million years
younger than Panderichthys. With its crocodile-shaped skull, and
paired fins with fin rays but strong internal limb skeletons,
*Tiktaalik* also resembles *Panderichthys* quite closely."
They also explain how *Tiktaalik* was a successful evolutionary
prediction:
"The Nunavut field project had the express aim of finding an
intermediate between *Panderichthys* and tetrapods, by searching in
sediments from the most probable environment (rivers) and time (early
Late Devonian)."
They compare and contrast features of *Panderichthys* and *Tiktaalik*:
"In some respects, *Tiktaalik* and *Panderichthys* are straightforward
fishes: they have small pelvic fins, retain fin rays in their paired
appendages and have well-developed gill arches, suggesting that both
animals remained mostly aquatic. In other regards, *Tiktaalik* is more
tetrapod-like than *Panderichthys*. The bony gill cover has
disappeared, and the skull has a longer snout (Fig. 1). These changes
probably relate to breathing and feeding, which are linked in fishes
because the movements used for gill ventilation can also be used to
suck food into the mouth. A longer snout suggests a shift from sucking
towards snapping up prey, whereas the loss of the gill cover bones
(which turned the gill cover into a soft flap) probably correlates
with reduced water flow through the gill chamber. The ribs also seem
to be larger in Tiktaalik, which may mean it was better able to
support its body out of water."
A more significant character from the evolutionary viewpoint is the
progress towards the tetrapod ear:
"Two aspects of *Tiktaalik's* anatomy relate to the origin of new
structures in tetrapods: the ears and limbs. The tetrapod middle ear
has arisen as a modification of the fish spiracle (a small gill slit)
and hyomandibula (a bone supporting the gill cover). *Panderichthys*
possesses a widened spiracle, interpreted as the intake for air or
water, and a shortened hyomandibula. *Tiktaalik* shows an almost
identical condition, but with an even wider spiracle, indicating that
this morphology too is genuinely transitional."
A later study showed that the hyomandibular of *Tiktaalik* also was
transitional, being smaller than that of *Eusthenopteron* (another
transitional fish that lived slightly before *Panderichthys* and may
have been ancestral to it) but not as small as that of
*Acanthostega*. This is nicely illustrated in the following website:
http://chronicle.uchicago.edu/081023/tiktaalik.shtml
The hyomandibular developed into the stapes ("stirrup") of the middle
ear of land vertebrates. [Much later, mammals added the incus and
malleus, the "anvil" and "hammer"--I forget which is which.] The
spiracle became the middle ear cavity and the Eustachian tube.
More later, when I have more time.
Peter Nyikos
Boikat
> For a long time I have been a critic of people who are too ready to
> claim that this and that discovery was "predicted by evolutionary
> theory," but even I cannot deny the appropriateness of applying that
> to the discovery of *Tiktaalik*, a transitional form between lobefin
> fish and tetrapods of the Devonian.
>
> The transitional status of *Tiktaalik* was brilliantly explained by
> Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> _Nature_:
>
> http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
> Since this article may not be available without some sort of
> subscription or payment of fee, I will be quoting quite a bit from it
> on this thread. In brief: there are lots of characters in the skull
> (especially the region of the ear) and fins that are intermediate
> between that of *Panderichthys*, another transitional lobefin, and
> such primitive tetrapods as *Acanthostega* and *Ichthyostega*. You
> can read a bit about them in the following site, which is available
> free of charge:
>
> http://chronicle.uchicago.edu/081023/tiktaalik.shtml
>
> But now, on to why I call this discovery a prediction of evolutionary
> theory. The following quote from another good website (also available
> free of charge) on *Tiktaalik* explains that part:
>
> _____________ begin excerpt
> it was not unforeseen. The paleontologists who found Tiktaalik went
> looking for it. Previous research suggested that vertebrates' invasion
> and fellow researchers searched for fossils in 375 million year old
> rocks that had preserved a river delta ecosystem. Having studied other
> organisms from this water/land transition, the paleontologists knew
> what sort of animal they were looking for. And when they did discover
> Tiktaalik (after five separate expeditions to Canada), it wasn't much
> of a surprise: Tiktaalik had the set of characteristics that they had
> expected to find in such an organism. In sum, discovering Tiktaalik
> simply confirmed many of the hypotheses biologists had held for a long
> time regarding the origin of terrestrial vertebrates.
>
> Don't lay too much store by that "In sum" bit--it's the kind of
> statement I've often criticized as too general to be adequate. It is
> the part that came before that delivers the goods. One does not go on
> such exorbitantly expensive expeditions to remote places unless the
> places were carefully picked on the basis of implicit predictions.
>
> You see, it wasn't some easily accessible place in Canada to which
> they went. It was to Ellesmere Island in Nunavut, Arctic Canada.
>
> Peter Nyikos
> Professor, Dept. of Mathematics -- standard disclaimer--
> University of South Carolinahttp://www.math.sc.edu/~nyikos/
> nyikos @ math.sc.edu
Pagano should read your post, but he will not be able to see it. It's
a "cognitive dissonance" thing.
Boikat
Boikat
jillery
<nyi...@bellsouth.net> wrote:
>For a long time I have been a critic of people who are too ready to
>claim that this and that discovery was "predicted by evolutionary
>theory," but even I cannot deny the appropriateness of applying that
>to the discovery of *Tiktaalik*, a transitional form between lobefin
>fish and tetrapods of the Devonian.
>
>The transitional status of *Tiktaalik* was brilliantly explained by
>Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
>_Nature_:
>
>http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
>Since this article may not be available without some sort of
>subscription or payment of fee, I will be quoting quite a bit from it
>on this thread. In brief: there are lots of characters in the skull
>(especially the region of the ear) and fins that are intermediate
>between that of *Panderichthys*, another transitional lobefin, and
>such primitive tetrapods as *Acanthostega* and *Ichthyostega*. You
>can read a bit about them in the following site, which is available
>free of charge:
>
>http://chronicle.uchicago.edu/081023/tiktaalik.shtml
>
>But now, on to why I call this discovery a prediction of evolutionary
>theory. The following quote from another good website (also available
>free of charge) on *Tiktaalik* explains that part:
>
>_____________ begin excerpt
>Tiktaalik is important, well-preserved, and certainly newsworthy — but
>it was not unforeseen. The paleontologists who found Tiktaalik went
>looking for it. Previous research suggested that vertebrates' invasion
>of land took place about 375 million years ago in a river — so Shubin
>and fellow researchers searched for fossils in 375 million year old
>rocks that had preserved a river delta ecosystem. Having studied other
>organisms from this water/land transition, the paleontologists knew
>what sort of animal they were looking for. And when they did discover
>Tiktaalik (after five separate expeditions to Canada), it wasn't much
>of a surprise: Tiktaalik had the set of characteristics that they had
>expected to find in such an organism. In sum, discovering Tiktaalik
>simply confirmed many of the hypotheses biologists had held for a long
>time regarding the origin of terrestrial vertebrates.
>============ end of excerpt from
>http://evolution.berkeley.edu/evolibrary/news/060501_tiktaalik
>
>Don't lay too much store by that "In sum" bit--it's the kind of
>statement I've often criticized as too general to be adequate. It is
>the part that came before that delivers the goods. One does not go on
>such exorbitantly expensive expeditions to remote places unless the
>places were carefully picked on the basis of implicit predictions.
>
>You see, it wasn't some easily accessible place in Canada to which
>they went. It was to Ellesmere Island in Nunavut, Arctic Canada.
Also documented in "Your Inner Fish" by Neil Shubin. Great book.
Quantum Leaper
Most likely the article has to many big words.
pnyikos
> On Aug 31, 10:38 am, pnyikos <nyik...@bellsouth.net> wrote:
> > For a long time I have been a critic of people who are too ready to
> > claim that this and that discovery was "predicted by evolutionary
> > theory," but even I cannot deny the appropriateness of applying that
> > to the discovery of *Tiktaalik*, a transitional form between lobefin
> > fish and tetrapods of the Devonian.
>
> > The transitional status of *Tiktaalik* was brilliantly explained by
> > Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> > _Nature_:
>
> >http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
> > Since this article may not be available without some sort of
> > subscription or payment of fee, I will be quoting quite a bit from it
> > on this thread.
Indeed, now that I am trying to look at it from my home, where I do
not have a subscription, all I get is an abstract and instructions on
what I need to do to look at the rest.
So far, your prediction is holding up. I replied to him on another
thread, and gave him a link to this one. I haven't seen a reply from
him, but Ray Martinez replied and completely ignored the information
on this thread, so I challenged him to take a look. No sign of him
having done it so far. Certainly he hasn't responded to my challenge
on that thread:
http://groups.google.com/group/talk.origins/msg/8b500bd9637f2364
Peter Nyikos
Boikat
Boikat
jcon
I saw a fantastic talk by Neil Shubin on the
discovery of Tiktaalik. The discovery was the
culmination of a remarkable multi-disciplinary
investigation that included microbiology, geology,
and a lot of stuff in between. Truly, science at
its best.
When I hear about things like that, it makes
me sorry for the people who have buried their
heads so far in the sand (or up their asses)
that they can't appreciate its beauty at any level.
-jc
On Aug 31, 10:38 am, pnyikos <nyik...@bellsouth.net> wrote:
> For a long time I have been a critic of people who are too ready to
> claim that this and that discovery was "predicted by evolutionary
> theory," but even I cannot deny the appropriateness of applying that
> to the discovery of *Tiktaalik*, a transitional form between lobefin
> fish and tetrapods of the Devonian.
>
> The transitional status of *Tiktaalik* was brilliantly explained by
> Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> _Nature_:
>
> http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
> Since this article may not be available without some sort of
> subscription or payment of fee, I will be quoting quite a bit from it
> on this thread. In brief: there are lots of characters in the skull
> (especially the region of the ear) and fins that are intermediate
> between that of *Panderichthys*, another transitional lobefin, and
> such primitive tetrapods as *Acanthostega* and *Ichthyostega*. You
> can read a bit about them in the following site, which is available
> free of charge:
>
> http://chronicle.uchicago.edu/081023/tiktaalik.shtml
>
> But now, on to why I call this discovery a prediction of evolutionary
> theory. The following quote from another good website (also available
> free of charge) on *Tiktaalik* explains that part:
>
> _____________ begin excerpt
> Tiktaalik is important, well-preserved, and certainly newsworthy but
> it was not unforeseen. The paleontologists who found Tiktaalik went
> looking for it. Previous research suggested that vertebrates' invasion
> of land took place about 375 million years ago in a river so Shubin
> and fellow researchers searched for fossils in 375 million year old
> rocks that had preserved a river delta ecosystem. Having studied other
> organisms from this water/land transition, the paleontologists knew
> what sort of animal they were looking for. And when they did discover
> Tiktaalik (after five separate expeditions to Canada), it wasn't much
> of a surprise: Tiktaalik had the set of characteristics that they had
> expected to find in such an organism. In sum, discovering Tiktaalik
> simply confirmed many of the hypotheses biologists had held for a long
> time regarding the origin of terrestrial vertebrates.
> ============ end of excerpt fromhttp://evolution.berkeley.edu/evolibrary/news/060501_tiktaalik
>
> Don't lay too much store by that "In sum" bit--it's the kind of
> statement I've often criticized as too general to be adequate. It is
> the part that came before that delivers the goods. One does not go on
> such exorbitantly expensive expeditions to remote places unless the
> places were carefully picked on the basis of implicit predictions.
>
> You see, it wasn't some easily accessible place in Canada to which
> they went. It was to Ellesmere Island in Nunavut, Arctic Canada.
>
> Peter Nyikos
> Professor, Dept. of Mathematics -- standard disclaimer--
pnyikos
Where was it held?
> The discovery was the
> culmination of a remarkable multi-disciplinary
> investigation that included microbiology, geology,
> and a lot of stuff in between. Truly, science at
> its best.
Can you recall how microbiology entered into it? Offhand I can't
imagine where it would have come into play, unless we are talking
about sarcopterygian fishes in general.
> When I hear about things like that, it makes
> me sorry for the people who have buried their
> heads so far in the sand (or up their asses)
> that they can't appreciate its beauty at any level.
>
> -jc
Indeed, that is the way I feel about it too. Thanks for sharing.
Peter Nyikos
Steven L.
"pnyikos" <nyi...@bellsouth.net> wrote in message
news:56f2a51d-894c-401f...@a7g2000yqb.googlegroups.com:
> On Aug 31, 11:38 am, pnyikos <nyik...@bellsouth.net> wrote:
>
> > The transitional status of *Tiktaalik* was brilliantly explained by
> > Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> > _Nature_:
> >
> > http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
> This "News and Views" article compares *Tiktaalik* with a slightly
> earlier (by ca. 2 mya) transitional form, *Panderichthys*, on the one
> hand, and a later primitive tetrapod, *Acanthostega* on the other.
> About the former, the authors write [citations omitted]:
>
> "Panderichthys* is vaguely crocodile-shaped and, unlike the rather
> conventional osteolepiform fishes farther down the tree, looks like a
> fish-tetrapod transitional form. The shape of the pectoral fin
However, Acanthostega still had *seven* fingers on each rear limb (and
perhaps on its front limbs as well). When did evolution finally settle
on five? And which species was first to have five?
Too bad the seven-finger arrangement lost out. It would have been fun
for hominids to do arithmetic in base 14.
-- Steven L.
Friar Broccoli
> "pnyikos" <nyik...@bellsouth.net> wrote in message
>
> news:56f2a51d-894c-401f...@a7g2000yqb.googlegroups.com:
>
>
>
>
>
>
>
>
>
> > On Aug 31, 11:38 am, pnyikos <nyik...@bellsouth.net> wrote:
>
> > > The transitional status of *Tiktaalik* was brilliantly explained by
> > > Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> > > _Nature_:
>
> > >http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
> > This "News and Views" article compares *Tiktaalik* with a slightly
> > earlier (by ca. 2 mya) transitional form, *Panderichthys*, on the one
> > hand, and a later primitive tetrapod, *Acanthostega* on the other.
> > About the former, the authors write [citations omitted]:
>
> > "Panderichthys* is vaguely crocodile-shaped and, unlike the rather
> > conventional osteolepiform fishes farther down the tree, looks like a
> > fish-tetrapod transitional form. The shape of the pectoral fin
> > skeleton and shoulder girdle are intermediate between those of
> > osteolepiforms and tetrapods, suggesting that *Panderichthys* was
> > beginning to 'walk', but perhaps in shallow water rather than on
> > land."
>
> > By the way, osteolopiform fishes have been "rehabilitated" by the
> > authors as transitional between still earlier lobefins and tetrapods
> > in:
OK, let's see here.
7-5=2 !!
So *information* about 2 fingers/toes was LOST !!!
Isn't that a successful prediction of deterioration since
creation !!!!?
jcon
> On Sep 6, 1:06 pm, jcon <cirej...@yahoo.com> wrote:
>
> > I saw a fantastic talk by Neil Shubin on the
> > discovery of Tiktaalik.
>
> Where was it held?
>
> > The discovery was the
> > culmination of a remarkable multi-disciplinary
> > investigation that included microbiology, geology,
> > and a lot of stuff in between. Truly, science at
> > its best.
>
> Can you recall how microbiology entered into it? �Offhand I can't
> imagine where it would have come into play, unless we are talking
> about sarcopterygian fishes in general.
>
It's been a while since I saw the talk (and it's *way*
outside my field), but as I remember it, the
details of the gene expression in the formation
of fins/fingers played a key role in determining
the exact time period where one would expect to
find this "missing link".
You can view the lecture here:
http://vmsstreamer1.fnal.gov/Lectures/Colloquium/110420Shubin/index.htm
-jc
jillery
wrote:
>On Sep 6, 3:31�pm, pnyikos <nyik...@bellsouth.net> wrote:
>> On Sep 6, 1:06 pm, jcon <cirej...@yahoo.com> wrote:
>>
>> > I saw a fantastic talk by Neil Shubin on the
>> > discovery of Tiktaalik.
>>
>> Where was it held?
>>
>> > The discovery was the
>> > culmination of a remarkable multi-disciplinary
>> > investigation that included microbiology, geology,
>> > and a lot of stuff in between. Truly, science at
>> > its best.
>>
>> Can you recall how microbiology entered into it? �Offhand I can't
>> imagine where it would have come into play, unless we are talking
>> about sarcopterygian fishes in general.
>>
>
>It's been a while since I saw the talk (and it's *way*
>outside my field), but as I remember it, the
>details of the gene expression in the formation
>of fins/fingers played a key role in determining
>the exact time period where one would expect to
>find this "missing link".
>
>You can view the lecture here:
>http://vmsstreamer1.fnal.gov/Lectures/Colloquium/110420Shubin/index.htm
I found a link to an interview with Neil Shubin:
http://itc.conversationsnetwork.org/shows/detail3553.html#
About 13 minutes into it, he starts talking about how he uses
molecular biology and DNA from living organisms to make predictions
about what he should find in the fossil record, and vice versa.
Steven L.
"Friar Broccoli" <eli...@gmail.com> wrote in message
news:73282ca6-79a6-4511...@h14g2000yqi.googlegroups.com:
Maybe God didn't want to have to invent The Fourteen Commandments.
http://www.youtube.com/watch?v=HE7tTT8khf0
-- Steven L.
jcon
> On Tue, 6 Sep 2011 20:00:06 -0700 (PDT), jcon <cirej...@yahoo.com>
That's right, because God is so smart that in addition to
burying the fossils of animals that never existed, he
hid remnant DNA in living animals and humans.
I guess when you're that awesome, you just can't
resist fucking with people.
-jc
r norman
wrote:
>On Sep 6, 3:31�pm, pnyikos <nyik...@bellsouth.net> wrote:
>> On Sep 6, 1:06 pm, jcon <cirej...@yahoo.com> wrote:
>>
>> > I saw a fantastic talk by Neil Shubin on the
>> > discovery of Tiktaalik.
>>
>> Where was it held?
>>
>> > The discovery was the
>> > culmination of a remarkable multi-disciplinary
>> > investigation that included microbiology, geology,
>> > and a lot of stuff in between. Truly, science at
>> > its best.
>>
>> Can you recall how microbiology entered into it? �Offhand I can't
>> imagine where it would have come into play, unless we are talking
>> about sarcopterygian fishes in general.
>>
>
>It's been a while since I saw the talk (and it's *way*
>outside my field), but as I remember it, the
>details of the gene expression in the formation
>of fins/fingers played a key role in determining
>the exact time period where one would expect to
>find this "missing link".
>
>You can view the lecture here:
>http://vmsstreamer1.fnal.gov/Lectures/Colloquium/110420Shubin/index.htm
>
I think you mean "molecular biology". Microbiology is a rather
different field.
jcon
> On Tue, 6 Sep 2011 20:00:06 -0700 (PDT), jcon <cirej...@yahoo.com>
my part. Thanks for pointing it out.
This is particularly embarrassing because PZ Myers recently
took Ann Coulter to task for no knowing the difference. Please
trust that I would proof read a book better than an USENET post.
-jc
jillery
That is among my Top Fourteen favorite Mel Brooks moments :)
Jeffrey Turner
But 10-5=9
More important, we can't swim as well as our ancestors.
>> Too bad the seven-finger arrangement lost out. It would have been fun
>> for hominids to do arithmetic in base 14.
We'd have lost all those words we can write in hex.
--Jeff
pnyikos
> On Sep 1, 4:30 pm, pnyikos <nyik...@bellsouth.net> wrote:
>
> > On Aug 31, 1:25 pm, Boikat <boi...@bellsouth.net> wrote:
>
> > > On Aug 31, 10:38 am, pnyikos <nyik...@bellsouth.net> wrote:
> > > > The transitional status of *Tiktaalik* was brilliantly explained by
> > > > Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> > > > _Nature_:
>
> > > >http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
> > > > Since this article may not be available without some sort of
> > > > subscription or payment of fee, I will be quoting quite a bit from it
> > > > on this thread.
another _Nature_ article on Tiktaalik, it is available free of charge:
http://www.nature.com/nature/journal/v440/n7085/fig_tab/440747a_F1.html
It shows the main animals we have been talking about here:
Eusthenopteron, Panderichthys, Tiktaalik, Acanthostega, Ichthyostega
along with a bit of information on each. It also has footnotes to
four references, but those can only be found in the main article, so I
am providing them here:
1. Daeschler, E. B. , Shubin, N. H. & Jenkins, F. A. Jr , Nature
440, 757–763 (2006). | Article |
16. Jarvik, E. Basic Structure and Evolution of Vertebrates
(Academic, New York, 1980).
17. Ahlberg, P. E. & Milner, A. R. Nature 368, 507–514 (1994). |
Article | ISI |
18. Gradstein, F. M. et al. A Geologic Time Scale 2004 (Cambridge
Univ. Press, 2005).
The two |Article| bits are links in the original to the actual
articles, while |ISI| takes you some information about the article in
"Web of Knowledge". The url for it is even longer than the abstract,
so I'm not posting it here.
Abstract: A series of new fossil discoveries, coupled with cladistic
analysis of old and new data, is beginning to resolve the origin of
tetrapods into a documented sequence of character acquisition.
Devonian tetrapods were more fish-like than believed previously,
whereas Lower Carboniferous tetrapod faunas contain early
representatives of the amphibian and amniote lineages. These very
different assemblages are separated by a 20-million-year 'Tournaisian
gap' which has yielded very few tetrapod fossils.
the issue of the horse sequence.
http://groups.google.com/group/talk.origins/browse_thread/thread/2c727140e04c5b74/eef80b9aeb5ea73f
Peter Nyikos
pnyikos
> On Sep 1, 4:30 pm, pnyikos <nyik...@bellsouth.net> wrote:
>
> > On Aug 31, 1:25 pm, Boikat <boi...@bellsouth.net> wrote:
>
> > > On Aug 31, 10:38 am, pnyikos <nyik...@bellsouth.net> wrote:
> > > > The transitional status of *Tiktaalik* was brilliantly explained by
> > > > Per Erik Ahlberg and Jennifer A. Clack in the 6 April 2006 issue of
> > > > _Nature_:
>
> > > >http://www.nature.com/nature/journal/v440/n7085/full/440747a.html
>
> > > > Since this article may not be available without some sort of
> > > > subscription or payment of fee, I will be quoting quite a bit from it
> > > > on this thread.
http://www.nature.com/nature/journal/v440/n7085/fig_tab/440747a_F1.html
It shows the main animals we have been talking about here:
Eusthenopteron, Panderichthys, Tiktaalik, Acanthostega, Ichthyostega
along with a bit of information on each. It also has footnotes to
four references, but those can only be found in the main article, so I
am providing them here:
1. Daeschler, E. B. , Shubin, N. H. & Jenkins, F. A. Jr , Nature
440, 757–763 (2006). | Article |
16. Jarvik, E. Basic Structure and Evolution of Vertebrates
(Academic, New York, 1980).
17. Ahlberg, P. E. & Milner, A. R. Nature 368, 507–514 (1994). |
Article | ISI |
18. Gradstein, F. M. et al. A Geologic Time Scale 2004 (Cambridge
Univ. Press, 2005).
The two |Article| bits are links in the original to the actual
articles, while |ISI| takes you some information about the article in
"Web of Knowledge". The url for it is even longer than the abstract,
Abstract: A series of new fossil discoveries, coupled with cladistic
analysis of old and new data, is beginning to resolve the origin of
tetrapods into a documented sequence of character acquisition.
Devonian tetrapods were more fish-like than believed previously,
whereas Lower Carboniferous tetrapod faunas contain early
representatives of the amphibian and amniote lineages. These very
different assemblages are separated by a 20-million-year 'Tournaisian
gap' which has yielded very few tetrapod fossils.