Fossil Fish Sheds Light on Transition

[Pure_in_Heart]

Comments like this puzzle me. Every time a fossil discovery is posted, invariably a creationist will offer their own opinion of what it is or isn't supposed to be. Never mind that these opinions are coming from people with no relevant training in the field of paleontology and based on an article on the internet. But hey, that's all one needs to be an expert in paleontology right?

We are talking about science, not politics. Offer evidences, or shut up.

 

[LewisWildermuth]

The fossils are just some fragmentary skeletons, where are the scales, gills, and fins?

Pure_in_Heart, are you lying for Jesus or just making up things or just repeating things someone else told you?

 

[Pure_in_Heart]

While some tetrapod finds are fragmentary, many are not. For example, Acanthostega is well represented in the fossil record. Please see the following link:

http://www.devoniantimes.org/Order/re-acanthostega.html

You can also click on the links at the bottom of the page for more details. Also, you can check out other tetrapod fossils from the Devonian at the left of the page.

Please stop assuming that paleontologists are incompetent, evolution-indoctrinated ignoramuses that spend their time trying to prove evolution by turning "a few fossil fragments" into imaginary transitional species.

*note added* Many of the links on the bottom of that page are broken.. my apologies for not checking them out first. This link is good and shows the actual fossils of Acanthostega: http://tolweb.org/tree?group=Acanthostega&contgroup=%0DTerrestrial_Vertebrates&dynnodeid=12088&javaOff=true

Sorry, I don't concern any other fossils, but "Tiktaalik". Don't try to throw out a tub to the whale!

 

[Pete Harcoff]

We are talking about science, not politics. Offer evidences, or shut up.

Exactly, we are talking science. Which is why I find it odd that some creationists seem to act like they know more about paleontology then, well, paleontologists.

Anyway, if you want the full details you'll have to grab a copy of Nature.

Abstracts for the articles can be read online:

Here we report the discovery of a well-preserved species of fossil sarcopterygian fish from the Late Devonian of Arctic Canada that represents an intermediate between fish with fins and tetrapods with limbs, and provides unique insights into how and in what order important tetrapod characters arose. Although the body scales, fin rays, lower jaw and palate are comparable to those in more primitive sarcopterygians, the new species also has a shortened skull roof, a modified ear region, a mobile neck, a functional wrist joint, and other features that presage tetrapod conditions. (A Devonian tetrapod-like fish and the evolution of the tetrapod body plan)

Here we describe the pectoral appendage of a member of the sister group of tetrapods, Tiktaalik roseae, which is morphologically and functionally transitional between a fin and a limb. (The pectoral fin of Tiktaalik roseae and the origin of the tetrapod limb)​

 

[Pure_in_Heart]

Pure_in_Heart, are you lying for Jesus or just making up things or just repeating things someone else told you?

A pretty fun question, isn't it? Tell me which option you desire me to choose first.

 

[LewisWildermuth]

A pretty fun question, isn't it? Tell me which option you desire me to choose first.

I would prefer the repeating one, because unknowingly repeating lies is, IMHO, much more favorable then knowinly lying.

 

[Split Rock]

Sorry, I don't concern any other fossils, but "Tiktaalik". Don't try to throw out a tub to the whale!

Are you conceeding that we have other intermediates that demonstrate the water to land tetrapod transition?

In any case, you need to look at the Nature papers if you want to see the fossil.

Nature 440 (6 April 2006):

A Devonian tetrapod-like fish and the evolution of the tetrapod body plan
Edward B. Daeschler, Neil H. Shubin and Farish A. Jenkins, Jr

The pectoral fin of Tiktaalik roseae and the origin of the tetrapod limb
Neil H. Shubin, Edward B. Daeschler and Farish A. Jenkins, Jr




from the News and Views section (Nature 440, 747-749 (6 April 2006)):

In some respects, Tiktaalik and Panderichthys are straightforward fishes: they have small pelvic fins13, 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 water1. The only real peculiarity of Tiktaalik is its poorly ossified vertebral column that seems to contain an unusually large number of vertebrae.

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 hyomandibula14. Tiktaalik shows an almost identical condition, but with an even wider spiracle, indicating that this morphology too is genuinely transitional.

The pectoral fin skeleton of Tiktaalik is notable not only because of its transitional nature, but also because its excellent preservation has allowed the individual bones to be freed of the rock and manipulated to estimate ranges of movement2. It turns out that the distal part of the skeleton is adapted for flexing gently upwards — just as it would if the fin were being used to prop the animal up. Although these small distal bones bear some resemblance to tetrapod digits in terms of their function and range of movement, they are still very much components of a fin. There remains a large morphological gap between them and digits as seen in, for example, Acanthostega: if the digits evolved from these distal bones, the process must have involved considerable developmental repatterning. The implication is that function changed in advance of morphology.

 

[Pure_in_Heart]

Exactly, we are talking science. Which is why I find it odd that some creationists seem to act like they know more about paleontology then, well, paleontologists.

Anyway, if you want the full details you'll have to grab a copy of Nature.

Abstracts for the articles can be read online:

Here we report the discovery of a well-preserved species of fossil sarcopterygian fish from the Late Devonian of Arctic Canada that represents an intermediate between fish with fins and tetrapods with limbs, and provides unique insights into how and in what order important tetrapod characters arose. Although the body scales, fin rays, lower jaw and palate are comparable to those in more primitive sarcopterygians, the new species also has a shortened skull roof, a modified ear region, a mobile neck, a functional wrist joint, and other features that presage tetrapod conditions. (A Devonian tetrapod-like fish and the evolution of the tetrapod body plan)

Here we describe the pectoral appendage of a member of the sister group of tetrapods, Tiktaalik roseae, which is morphologically and functionally transitional between a fin and a limb. (The pectoral fin of Tiktaalik roseae and the origin of the tetrapod limb)
​

Are you telling me that you haven't read the original articles? Do you have the copy?

 

[Pete Harcoff]

Are you telling me that you haven't read the original articles? Do you have the copy?

Not yet, but I may have a look at it when I hit the library today (if they have a copy yet).

 

[Frumious Bandersnatch]

The fossils are just some fragmentary skeletons, where are the scales, gills, and fins?

A picture is attached.

 

[Pure_in_Heart]

I would prefer the repeating one, because unknowingly repeating lies is, IMHO, much more favorable then knowinly lying.

Well, you get it: you are unknowingly repeating the lie you yourself made up.

 

[Loudmouth]

We are talking about science, not politics. Offer evidences, or shut up.

What do you think this whole thread is about? If life originated in the water and moved onto land we would expect to find transitional fossils that have both aquatic and terrestrial adaptations. This is exactly what has been found. They found a fish with legs. In fact, they have a whole series of transtional fossils illustrating the evolution of those very legs and other terrestrial adaptations, such as an inner ear adapted for recieving air born sound waves.

How can you ask for evidence when the whole topic is about a new transitional fossil showing the evolution of fish moving onto land?

 

[Loudmouth]

Here is a great summary of the transitional features of the new find. It is written by Martin Brazeau (Martin B) of Internet Infidel's fame. He and Per Ahlberg are scientists within the field of tetrapod evolution. The site includes pictures of the actual fossils and other great info geared towards the creo vs. evo debate.

 

[awesome liver]

Possibly for a more efficient exchange of gases rather than having the whole skin area act as a "lung". This would be especially advantageous if the fish was developing armour as many Devonian fish did.

Note, I said "possibly". In lots of cases we just don't know enough to do more than speculate why a certain feature was advantageous at that particular time and place.



Because earlier speciation prevented the sharing of mutations which made reliance on lungs advantageous for the group which developed into terrestrial animals.

Way back when fish were the new kids on the block, there was a speciation which divided them into two groups. One was the sarcopterygii, which developed lobe-type fins. The other was the actinopterygii which developed the ray-type fin of modern fish.

The latter have swim bladders where the former had lungs, and Stephen J. Gould theorized that the swim bladder is a modified lung. This modification was never adopted by the sarcopterygii, because the species barrier never allowed it to migrate from the actinopterygii into the sarcopterygii.

Similarly, developments in the lineage of the sarcopterygii never migrated into the actinopterygii.

why? why are you responding? you know it just went over his head or he ignored it completely. ugh.

 

[awesome liver]

since the evolution deniers are prone to not reading anything, maybe pictures will work better.

a, Left lateral view; b, dorsal view with enlargement of scales; and c, ventral view with enlargement of anterior ribs. See Fig. 3 for labelled drawing of skull in dorsal view. Abbreviations: an, anocleithrum; bb, basibranchial; co, coracoid; clav, clavicle; clth, cleithrum; cbr, ceratobranchial; ent, entopterygoid; hu, humerus; lep, lepidotrichia; mand, mandible; nar, naris; or, orbit; psp, parasphenoid; ra, radius; suc, supracleithrum; ul, ulna; uln, ulnare. Scale bar equals 5 cm.

Unlike other tetrapodomorph fishes (1), Tiktaalik has reduced the unjointed lepidotrichia, expanded the radials to a proximal, intermediate and distal series, and established multiple transverse joints in the distal fin. The fin also retains a mosaic of features seen in basal taxa. The central axis of enlarged endochondral bones is a pattern found in basal sarcopterygians and accords with hypotheses that a primitive fin axis is homologous to autopodial bones of the tetrapod limb. In some features, Tiktaalik is similar to rhizodontids such as Sauripterus. These similarities, which are probably homoplastic, include the shape and number of radial articulations on the ulnare, the presence of extensive and branched endochondral radials, and the retention of unjointed lepidotrichia. Figures redrawn and modified from Glyptolepis, Eusthenopteron, Panderichthys, Acanthostega and Tulerpeton.

a, b, Anterolateral view. c, d, Ventral view. a, c, Resting posture with the fin partially flexed at the antebrachium. In this position the radius is slightly more flexed than the ulna. b, d, Resistant contact with a firm substrate entails flexion at proximal joints and extension at distal ones. The shoulder joint is flexed by ventral muscles, including the trans-coracoid muscle. The elbow is flexed (d, arrow 1), with slight pronation of the radius (d, arrow 2) and rotation of the ulna (d, arrow 3). The transverse joints distal to the ulnare and intermedium are extended (d, arrows 4).

 

[gaetan8888]

Hi

This fish don't bother me, if God created the life by using evolution, so be it, God can choose anyway He want to create life. That don't change anything to the Bible a Jesus Christ.

Gaetan

 

[Split Rock]

Well, you get it: you are unknowingly repeating the lie you yourself made up.

Will you admit you were wrong when you wrote that the article was based on a few fragments?

 

[AirPo]

We are talking about science, not politics. Offer evidences, or shut up.

No spin there.

 

[AirPo]

A pretty fun question, isn't it? Tell me which option you desire me to choose first.

How about answering the question.

 

[LewisWildermuth]

Well, you get it: you are unknowingly repeating the lie you yourself made up.

Well I was hoping you simply opened up your mouth and shot it off before thinking. Now I am not so sure it is that simple.

The fossils they are talking about are not just a few scattered bones, if you would have bothered to look at them you would have known this.

So you have not only lied out of ignorance, you also lied to me by not giving your answer after I fulfilled your request. You continue to compound the problem by being a jerk when caught in a lie instead of confessing the problem and correcting it.

Way to represent Christ to the people in this forum.