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That is a ridiculous argument. Technical and scientific terms rarely have the same meaning as they do in common usage. Anyone who has made a serious study of any scientific or engineering discipline is aware of this. Moreover, the precise meaning of some terms changes over time, sometimes radically. (Try looking at at the definitions of igneous rocks.) Consequently, your dictionary definitions have little or no relevance.The meaning of transitional
Beginning in the mid-15th century meaning “to transition” from the Latin transitio meaning “to go or cross over”, hence from one place or state to another. In the early 18th century transitionally still meant to change from one state, place, or style to another. Relative terms like transitioned or transitioning defined the end result or process of changing. Today from Merriam Webster:
Transitional:
Marked by transition: involving, providing, or consisting of a passage, movement, or change from one state, condition, subject, place, etc., to another
Or Oxfords which defines it as
relating to or characteristic of a process or period of transition; change over; an interim
In music a middle tone in a chromatic escalation of three notes starting at one note of the scale to a final note in the scale, the middle note is a transitional (starting at one note of the scale, the middle note leads to the later note. Ex. In the key of C if I transitioned from F, F#, to G, the F# is NOT part of the C scale it creates a tension needing to be resolved). In modern genetics when a point mutation is replaced (such as when a purine is replaced by another purine or some other) a transition is said to have occurred.
That is a ridiculous argument. Technical and scientific terms rarely have the same meaning as they do in common usage. Anyone who has made a serious study of any scientific or engineering discipline is aware of this. Moreover, the precise meaning of some terms changes over time, sometimes radically. (Try looking at at the definitions of igneous rocks.) Consequently, your dictionary definitions have little or no relevance.
A "link" references the presence of intermediate characteristics. It does not mean that the organism is a direct descendent of specific earlier known organisms, or a direct ancestor of subsequent specific known organisms.Except that the actual meaning has not changed except for the purpose of equivocating by Evolutionary Biologists. Notice no reference to similar, or shared in common, or containing characteristics also found in two or more others, is even implied.
Even the dictionary portion of Biology Online gives this as the definition:
transitional
Relating to or marked by a transition; transitory
Also an organism that provides a link between earlier and later forms in evolution
What part of an in between form do you not get? Something allegedly earlier (in this case fish), the in between form (Tik if transitional), and then something that allegedly came after or as a result of (land-walking Tetrapods).
A "link" references the presence of intermediate characteristics. It does not mean that the organism is a direct descendent of specific earlier known organisms, or a direct ancestor of subsequent specific known organisms.
You are free to believe that is what it means, but that is not how evolutionary biologists or palaeontolgists use the term. You see, you don't get to define the term - the professionals who use the term get to define it. That means the equivocation is on your part. Not theirs.
You can either learn how terms are used by the professionals, or you can decide that you know more than the experts on how terms are to be used. Why would you do that?
-_- would you say that orange is an intermediate color between red and yellow? Because I would, knowing how light wavelengths work. Yet, I would never claim that the color red must have existed before the color orange or that the color yellow must have come into existence after the color orange to consider this color intermediate between the two. After all, it is the wavelengths between red and yellow physically, not chronologically."A "link" references the presence of intermediate characteristics. It does not mean that the organism is a direct descendent of specific earlier known organisms, or a direct ancestor of subsequent specific known organisms."
I did not insist it was a direct descendent of anything, or a direct ancestor of anything. Under the definition as revised to fit the hypothesis, YES of course Tik has some characteristics more in common with other fish and some in common with other modern bottom walking fish...so what?
It is and has been continuously used to show a relationship such that fish were developing toward land walking tetrapods, but we still have ample examples of bottom walking FISH and land walking tetrapods have been around for millions of years!
"A "link" references the presence of intermediate characteristics"
Intermediate: Coming BETWEEN two things....
In this case, both things already existed fully formed before it came into existence (thus not even intermediate)!
Here is the timeline...non-developed (regular fish), completely developed (land walking Tetrapods), then quasi developed (like Tik). Now since these things already existed fully formed before the latter less formed variety, this could be interpreted as implying devolution (just being sarcastic there though 100% logical).
-_- would you say that orange is an intermediate color between red and yellow? Because I would, knowing how light wavelengths work. Yet, I would never claim that the color red must have existed before the color orange or that the color yellow must have come into existence after the color orange to consider this color intermediate between the two. After all, it is the wavelengths between red and yellow physically, not chronologically.
-_- but if you adjust the wavelength of light gradually, starting at red, you will inevitably transition through orange before you'll see the yellow wavelengths.Yup! Not transitional! Great example.
Sorry it took so long, but I have a busy life, and when I looked the thread was not there so this time I went back and clicked on your link.
So here is an image of the actual fossil remains found. Using only what is actually there (badly crushed) it is almost impossible to say anything about the body except very general information, though based on this, assumptions have been made.
Later at the same site we found a rear section.
For an example of assumption, that its chest was more robust and housed primitive lungs of some sort, and that the evolution of hind legs actually began as enhanced hind fins, which are both speculative possibilities that cannot be known. The projection of primitive lungs is entirely hypothesis based speculation.
Now, there are things we can know from this fossil and things that are being assumed (the hypothesis based suppositins) but the problem is that people are believing these assumptions as if they are true or obvious facts.
We can know, for example, that Tik had gills, fins, and certain markings indicating it also had scales. The entire body portion however was totally flattened (many pieces of bone) and the two forward fins demonstrated in the fossil show no direct connection to the rest of the skeletal remains. That they originally could have been connected is a perfectly reasonable possibility, but the fossil itself (the actual data we have) does not demonstrate this.
Now look at the totally artistically contrived reconstruction and note how it exactly images what one would expect if the assumption portions were actually true? The actual fact that it is entirely fiction does not seem to matter among those convinced. Click the IMG
So this is a good place for me to start what I consider valid reasons to question the present interpretation (the hypothesis based narrative) as Tik being a transitional form.
So all the real evidence implies is that the actual fossil is that of an ancient variety of fish! Does it have actual amphibian or land walking tetrapod characteristics? No!
Does the narrative imply it does have these? Yes! Do the artistically contrived reconstructions imply these? Yes! So then what should a rational person put their trust in? The actual or the speculations and fictional images?
-_- they've had significantly more time to adapt and develop those skills via evolution.Excellent points. I would also like to point out that we have living organisms today which do a better job of being amphibious that the illustration of the imagined actual creature looks like it would be. Mudskippers and lung fish come to mind, as do some catfish and eel species.
-_- but if you adjust the wavelength of light gradually, starting at red, you will inevitably transition through orange before you'll see the yellow wavelengths.
Basically, even if Tiktaalik isn't in the direct lineage between fish and tetrapods, something like it was, and it is notable for its intermediate traits (just like how orange has intermediate wavelengths between red and yellow). It's highly unlikely that Tiktaalik has absolutely no genetic ties to that lineage either; it's probably an offshoot.
Excellent points. I would also like to point out that we have living organisms today which do a better job of being amphibious that the illustration of the imagined actual creature looks like it would be. Mudskippers and lung fish come to mind, as do some catfish and eel species.
Welcome to the discussion Gracia...most amphibians can live out of the water but prefer it, some must return to lay their eggs, and a few live IN the water (but also breathe air), but mudskippers and lungfish would suffocate if out of the water too long (like Tik, because after all they are fish).
True, Sir, but I've never seen anyone argue that *living* amphibious fish of any kind are themselves somehow transitional. Thank you for the welcome!
You are welcome for the welcome (lol) and I would not argue that living amphibious fish are transitional as they are still fish and amphibians already exist. Changes in a species (changes in a type of fish for example) happen by speciation, but this does not indicate a change from a fish into an amphibian (even after millions of years).
It is a shame that some simply want to hide their heads in the sand. If Tiktallik was the only transitional fossil they might have a very weak argument, but of course it is not. It is merely the first one found using the theory of evolution and geology together to predict where such a fossil should be found.
Since, and even before then there have been of course more finds. For example we have Acanthostega. It is even more "transitional" than Tiktaalik. It has clear fish and tetrapod traits:
Acanthostega - Wikipedia
"The 60 cm (24 in) Acanthostega had eight digits on each hand (the number of digits on the feet is unclear) linked by webbing, it lacked wrists, and was generally poorly adapted for walking on land. It also had a remarkably fish-like shoulder and forelimb.[2] "
So still not a modern tetrapod, but not a fish either.
Next we have Ichthyostega:
Ichthyostega - Wikipedia
" Until finds of other early tetrapods and closely related fishes in the late 20th century, Ichthyostega stood alone as the transitional fossil between fish and tetrapods, combining a fishlike tail and gills with an amphibian skull and limbs."
That article lists at least ten different stages between fish and tetrapods. Of course different fossils were discovered at different times. Tiktaalik merely filled one of the "gaps". And of course every fossil found creates two new "gaps". I suppose that some feel by denying one that all can be denied, but one has to look at the big picture and the big picture tells us that land animals evolved from fish.
What the heck, one more article that explains evolution to those willing to learn:
https://evolution.berkeley.edu/evolibrary/article/evograms_04
Aside from the predictable non-subtansive rant, you said
What you seem to believe is that everyone, including Shubin, declared Tik to be THE sole transitional, the actual LCA of all tetrapods.
Never happened...I never said such a thing (sadly also predictable)....
(like Tik, because after all they are fish).
The crushed chest area is NOT robust
The creature is very large
Robustness does not equal being for breathing...You know, even fish have a body cavity. But their ribs are not robust at all, since they are not needed for breathing.
Menton had declared that Tik lacked a bone-to-bone connection between the shoulder girdle and axial skeleton, and that this is REQUIRED for moving on land.
a) I never mentioned Menton and have never read anything written by Menton. If you asked me to name something he has written I literally would have to google it.
Also, Elephants shoulder bones are indeed connected to its skeleton (or it would fall to the ground)
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