Acanthostega - classified as a stem tetrapod of the Devonian. What Darwinism would claim is a "missing link" or "a transitional" between fish and amphibians.
Ahhhh, Good ol' Acanthy; the mainstay of the Darwinian hypothesis for probably the last two decades or so. A funky kind of chimera tetrapod, with multiple digits on its fore (and presumably hind) limb. Awwwww.....
I'm of the thought that Acanthostega - besides being a chimeromorph of sorts - exhibited a Hox gene malfunction in the doubling of digits - digits that Acanthostega already possessed from the time it was created. I don't think that the evidence warrants the conclusion that Acanthostega arose from a fish ancestor. Here's why:
The doubling of digits, also known as polydactyly, is not uncommon even for modern day organisms (most notably amphibians) where digits and even whole appendages are doubled, due to a malfunction/mutation in the genes which code for proper limb placement. These genes are known as Hox genes, and essentially do the job of plugging in where exactly an antenna, limb, or leg goes. Remember news reports several years back about geneticists getting a fruit fly to grow legs where its antennae should've been? Hox genes at work (or out to lunch, presumably)...
1. In order to go from fish to amphibian, the fish "fin" needs to dump the lepidotrichia - the fin rays of presumed fish ancestors - and generate the more complex articulated digit array of later tetrapods (like Acanthostega).
This complexity would include:
-Change in structural composition (from partially cartilaginous fins to fully ossified endochondral skeletal digits)
-Construction of the digits themselves (running the risk of hyperphalangy in the process)
-Functional articulation of skeletal structure into working digit array
-New musculature (including tendons), as well as new attachment points to the skeletal frame
-Structuring of nerve endings
-And finally, new and novel developmental pathways during embryonic development to make way for all of the above. (i.e., proper Hox genes clusters, Sonic hedgehog signalling, and regulation/timing of these biochemical systems.)
And so on. Basic upshot is that in order for the more complex limb with digits to have arisen from a fin design, the fin design would need to have been scrapped completely - the fins or lepidotrichia would be gone. Hence, the arrival of a new bauplan (body design) requiring an increase in complex functional information to arise on the genetic level, properly regulated so as to code for functioning limbs instead of thalidomide nightmares (or hyperphalangic hindrances - imagine Nosferatu picking his nose or wiping his arse with 10 foot long triple-hinged fingers)...
In other words, we need the genes to 'pop up' with all the new info for the hi-tech gadgets. Natural selection and mutation can only work with what's there - it can't do the biochemical equivalent of alchemy and make things (like complex and interrelated biochemistry to regulate limb-with-digit development) "appear" out of nowhere.
Some evolutionists will posit that the digits came from previous "radial" bones in the fish ancestor, and all that was needed was a mutation in order to duplicate the radials, until after numerous disasters and roulette wheel spins, we have a winner! Digits!
But consider: What would be happening is an unregulated growth algorithm running rampant due to mutation (for this is a non-guided process according to Darwin's hypothesis). If an indiscriminate duplicating of the radials - or internal bone structure of the fin - is taking place in the presumed fish ancestor, then the possibility for a non-functional result, such as hyperphalangy, is much more likely. (This is, of course, assuming that we've even gotten to the point of having any semblance of a functioning digit morphology for mutation to act upon - with all of the morphological and biochemical prerequisites mentioned above having been met.)
And natural selection would more likely weed out any genetic deviation from the fitness norm (depending on how strictly niched the organism is to it's ecology) rather than preserve potentially nascent structures. What we see in tetrapod fossils already are fully formed and (in most cases) functional limbs (even in a Hox gene example like Acanthostega, which has a fully digitated limb, not a fin. Which is why I think it's more reasonable to assume that Acanthostega's presumably mutated multi-digited limb happened *after* it was created, fully formed.)
So as with Vegas, so too in nature: The house always wins. "Hopeful monsters" aren't conscious capitalist ventures - faith in mutation and natural selection to "create miracles" is a false idealism, and I think it says more about Western thoughts on "success" and "beating the odds" than it does about factual biology.
Evolutionists tend to espouse the possibility of bioengineering wonders via mutation, but they seem to overlook the fact that their scenarios - while highly speculative and lacking experimental verification as is - are already assuming a complex state of affairs from the get go. To put it differently: They get the cart before the horse. They imagine what mutation can do in a fish limb, never realizing that the fish itself (not to mention a tetrapod like Acanthostega) is an already complex and fully functioning organism, complete with fully functional structures, both physiologically and biochemically.
Which is especially important to our scenario, since they propose that duplicating bones in the fin is enough to create digits - Well, where did the complex biochemical signaling for all of this duplicating and placing come from, in either fish or tetrapod? Where did the genetics come from to weave and form endochondral skeleton, musculature, nerve endings, and so on? Or cartilage? What about the ability of Hox genes to act as placement signaling for what later become interrelated morphological structures? Or the interlinked regulation between Shh and GLI3 expression, which is now understood as being an important factor in proper limb/digit development?...
These are the questions that evolutionists tend to overlook, unintentionally at times I think. The usual recourse is on the superficial: "It *looks* like a fin, therefore..."
2. Doubling or repetition of already existent genetic info (in this case, the genetic pathways for digit development in Acanthostega) does not constitute an increase in functional genetic info.
It's pure semantics to try to say that repeating an already complex signal is an increase in complexity. In the case of Hox gene duplication - and presumably the multi-digit state of Acanthostega - the complexity in the genome was already coded for: Acanthostega already had a fully functional limb with digits, which I believe mutated and doubled. (Polyphylangy! ...There's that word again.)
Anyhow, this business with having multiple digits, it's like copying and pasting an image multiple times on your computer: You may have more of the same image, and it may alter the content of a folder (more images, more hard drive space taken for more images), and the image itself may be altered in the process (lacking pixels, file becoming corrupted). But ultimately, the copying process itself does not account for the initial creation of the image, much less the computer. The creating of a specific image - as well as the computer - would require intent, purpose, intelligent input and direction.
Add on top of that: The image is a full, high res, 1 gig picture of the Sistine Chapel. That's about the level of specificity and detail we're dealing with when speaking about genetics (even for lil' Acanthostega baby fingers...)
And remember, this applies to the host of *other* features that need to be accounted for in an evolving "fish-to-tetrapod" scenario. These would include the evolution of neural pathways, metabolism, reproductive and developmental pathways, respiratory, locomotory (in the case of fish, respiration and locomotion go hand in hand - it needs to swim in order to breath!). And on and on and on... Picture: Sistine Chapel covering the interior of the NASA space shuttle.
Ultimately, this portion of Darwin's explanation is a Victorian creation narrative: Very ingenious in trying to explain things, but which... well... breaks all the cardinal rules of science. None of these hypothetical scenarios involving macro evolutionary increases is in any way observable, testable, or repeatable in a scientific, laboratory setting. And it runs contra to observed genetics.
...On the upside for Darwinism, however, here's a fairly positive example of macro evolution in action:
Yes, it's me. And yes, I got tagged on this: Portray yourself as you were in junior high/high school, and who you are now. (You see? Increase in information... maybe not complex or functional most of the time, however...)
So, here I am... was.... whatever... in all my junior high glory. And then, onto the future, which... is presently now. And stuff. Yeah...
Notice that I moved on from Hasidic locks to grocery bag stylin's. Koshrut and all that.
Colerase, PS CS, copy paper... More to come soon, minus the nerdiness. (Or maybe not...)