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Author
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Topic: pentadactilism again challenges the modern synthesis
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Bruce Fast
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Member # 924
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posted 31. January 2006 17:32
I know that pentadactilism has been used by others to challenge the varacity of the modern synthesis. However, I believe my approach to be novel. Further, because my approach is based upon very obtainable evidence, that of the common house cat, I believe that it will have some appeal.
Abstract:
Homology, and in particular pentadactylism, was presented by Darwin as evidence of common descent. This phenomenon, that all four-limbed vertebrates species* have no more than five digits on each limb, continues as evidence supporting the modern synthesis. I assert that this force in nature is stronger than the modern synthesis can accommodate to the point where the universality of the modern synthesis is brought into question. My assertion is that a polydactyl mutation exists and is relatively common, therefore because of the opportunistic nature of the modern synthesis, polydactylism should have found opportunity to dominate some species somewhere. It would appear, therefore, that rather than being totally opportunistic, nature is determined to hold to a prescribed pattern.
Body:
Opportunism is at the very core of the modern synthesis. It seems that every time that an environment is found, no matter how hostile it appears to be to life as we know it, life has found a way to adapt there. Surely nature has shown us just how opportunistic life can be. This, of course, supports the opportunistic nature of the modern synthesis.
The modern synthesis, by its very nature, must also be methodologically opportunistic. This is to say, if a way of solving a problem in nature is readily available, the modern synthesis dictates that it will be implemented.
If ever there was variety of form without variety of structure, it is in the terminus# of the vertebrate limb. One particular common requirement of this terminus is the need for larger size. We see this, for instance, in all animals that would benefit from being able to walk higher on snow, from desert animals, and from aquatic animals. Many of these animals have developed rather large feet and flippers. However, without fail, hiding in these appendages is a pentadactyl structure.
(A few notes about pentadactylism. Fewer than five digits are relatively common. Birds, for instance all have three digits in each wing, and four in each foot. The dinosaurs are also all* quartadactyl#. The prototypical cat has four digits on its hind foot. The three-toed sloth, of course, has three. Cloven hoofed animals have two digits, and hoofed animals have one. In all* mammals with less than five digits, a vestigial digit is reported. Birds do not seem to have a vestigial digit unless they have less than the prescribed number of digits.)
Now, if I am correct in my assertion that the modern synthesis obligates methodological opportunism, then there can be only two reasons why polydactylism is not a phenomenon: either for some reason opportunity is virtually not given to organisms to experiment with polydactylism, or the modern synthesis is inadequate in explaining this phenomenon.
I am, however, familiar with two animals that have experimented with polydactylism: house cats and humans. With humans, a child born with an extra digit either on his feet or hands is not the cause of alarm or surprise. Rather, the digit is analyzed as to function*. Often such digits are quite dysfunctional, not having muscular control, or being a partial digit bonded to one of the pentadacyl digits*. These digits are routinely removed. However, such digits are also periodically fully functional. In this case, it is often left to the child’s parents as to whether to remove the “oddity” or keep it*. Let it also be pointed out that polydactylism, amongst humans, is an hereditary trait – that most usually if a child is born polydactyl, polydactylism exists in his family tree#. Let it also be pointed out that there is no evidence in the literature of any negative characteristic associated with polydactylism – polydactyl children are not also seen to have any ‘associated’ handicap.
When I moved to the Canadian sub-arctic, I found the existence of polydactyl house cats to be commonplace. Often these cats would have 7 toes on a foot. As might be expected, polydactyl cats have particularly large feet. As there is a clear potential advantage offered to these cats in this snowy environment, the predominance of this feature would be seen as a virtue, rather than a deficit. After all, isn’t that what natural selection is all about.
So now we have two very separate species, in separate families, both of whom are experimenting with polydactylism. Yet the number of species, past and present, that have prototypically been pentadactyl is in the order of a million*. The number of species that clearly benefit from large appendages are in the order of ten thousand*. Why, I as, have none of these species implemented polydactylism as their norm? Certainly it is not because of lack of opportunity. Certainly it is not because there is some weave in the genes that says, “if you get a polydactyl mutation, you will also be born without a tongue” or something weird like that. No, it is because organisms are more determined to follow a pattern than they are determined to take opportunity. And this is counter to anything predicted by the modern synthesis!
There are a number of other interesting characteristics of pentadactylism which are worthy of note. The first four-limbed vertebrates were actually polydactyl&. Pentadactylism, however, has been the standard since the dawning of the amphibians&. Further, it is reported that pentadactylism evolved at least twice(1). In a way, it could be said that pentadactylism evolved four times in that front and rear limbs seem to have significantly different genetic makeup. Lastly, Denton and others point out that embryology suggests that pentadactylism develops from different genes in different organisms&. This history, especially the suggestion that pentadactylism evolved multiple times, and that pentadactylism is the result of different gene sets in different organisms, support a view of pentadactylism that is much more comfortable with organisms being determined to follow a pattern than they are with organisms following the path described by the modern synthesis.
In conclusion,
Pentadactylism, one of the hallmarks of evolutionary proof, proves to be a difficult fit with the modern synthesis at best. The modern synthesis obligates methodological opportunism. Pentadactyl vertebrates certainly have had many opportunities to benefit from evolving large appendages. Yet these animals have consistently avoided the polydactyl solution. In addition, evidence suggests that this pattern formed multiple times in the history of animals, and evidence suggests that there are different gene sets in different animals that drive the development of this pattern. All of this does not bode well for the claim of universality that the modern synthesis currently enjoys. A new explanation is called for, an explanation that recognizes organisms’ determination to hold to a pattern.
Further Research:
This concept naturally leads to a number of valuable research opportunities:
1: If it can be shown that the pentadactyl house cat is more prevalent in snowier areas, then it could be asserted that natural selection is validating my assertion that polydactylism is useful as a snowshoe effect. A mapping of the prevalence of the polydactyl house cat with compared with the duration of snow on the ground would be of interest.
2: It would be interesting to see if stable polydactylism could be achieved. If stable polydactylism is easy to achieve, this would support my assertion. If stable polydactylism is not achievable, then the character of nature’s determination to be pentadactyl would be better understood. I therefore propose a house cat breading program with the purpose of producing a breed that is consistently polydactyl.
3: The more prevalent the polydactyl mutation, the greater the support for my claim. I therefore propose an active program of seeking out all instances of the polydactyl mutation.
4: More such phenomenon would prove a greater challenge to the modern synthesis. I would define a bona-fide example of nature choosing to follow a prescribed pattern rather than opportunism as having the following features:
a: The pattern must exist on at least the order level – where all species within the order have the pattern.
b: Mutations which are an exception to the pattern must exist, but must not be the prototype for any species within the scope of the pattern.
c: The mutation must, in environments experienced by the some of these species, appear to be beneficial as implemented with the naturally occurring mutation.
1. Coates M., "New paleontological contributions to limb ontogeny and phylogeny," In: J. R. Hinchcliffe (ed.), Developmental Patterning of the Vertebrate Limb, Plenum Press, New York, 1991, 325-337; Coates M. I., The Devonian tetrapod Acanthostega gunnari Jarvik: postcranial anatomy, basal tetrapod interrelationships and patterns of skeletal evolution, transactions of the Royal Society of Edinburgh, 1996, vol. 87, pp. 363-421.
* I think, but do not know, that this is true. If not fully accurate, please correct me.
# I am looking for better terminology here.
& Facts or source material required.
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Krauze
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Member # 1119
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posted 31. January 2006 19:06
Hi Bruce,
"This phenomenon, that all four-limbed vertebrates species* have no more than five digits on each limb"
Actually, some tetrapods (terrestrial vertebrates) have more than five digits. Acanthostega, an early tetrapod, had eight digits on the forelimb and seven digits on the hindlimb. For more on this, including evolutionary biology's perspective on it, see Stephen Jay Gould's essay, "Eight Little Piggies" in his book of the same name.
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KBC1963
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Member # 1868
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posted 16. February 2006 00:53
Bruce,
The continuity of the five digit system indeed fly's in the face of oportunistic change. I have often argued about this topic and brought the same evidences to bear , most notably the fact that a totally separate set of genes codes for an almost perfect replica of that system.
The typical reply is that the fact that 5 is predominant is that it has the best all around functional selectivity which adds up to nothing more than circular reasoning.
The logic of asking why isn't something selected for automaticly when it is apparent that based on enviromental factors alone the 6 is better than the 5 is without fault.
I reflect back on the just so story of the giraffe and I hear the argument about how mutation is magically present to allow for a multitude of adaptations to help the poor starving animal gain the ability to reach food by forming a perfectly functional extra 10 feet of neck and I wonder too why a cat can't get a friggin spare dactyl when its obvious that it would be selectable.
And the evolutionary answer is:
The fact that evolution happens over long periods of time is why we don't see it in action and the fact that 6 toes are showing up may mean that in another million years cats probably will get that digit as standard equiptment but for now we must have faith that evolutions model is active and evolving everything bit by bit.
I think one other argument would be that since cats are domesticated that they are not subjected to the same selective pressures that the strictly wild creatures are so they would not be a viable choice for testing.
Bruce I have found that argument in this vein no matter how well concieved and backed never seems to go beyond the realm of philosophical conceptions and even if everything had 50 toes or just one the evolutionary reply would remain exactly the same and we would still be no further for our efforts. The fact that we haven't been able to quantify any part of the process in any way that can empirically break an argument that allows for any outcome is the main stumbling block.
I think one of the pertinent studies that apply to this situation was the peppered moth study that showed that selection advantage could change a mostly light colored population into a mostly dark colored population to be true the only problem of course was that when the environmental factors changed back to select the lighter as more selectable they indeed returned.
The final question is does selection advantage ever allow recessive possibility to become dominant? You realize of course that in order for evolutions engine to really work that each mutation must be a dominant trait because if it was recessive then natural selection would be at war with recssivity, I wonder who the winner would be?
I have a funny joke that falls in line with this subject that I must pass on:
If evolution makes choices based on selectable advantage and we can believe that higher levels of intelligence are more selectable than lower could you explain the existence of all the friggin idiots alive today?
of course this was a joke meant to poke fun at evolutionists but it contains the thread of truth and we could easily say that because rich people have better life expectancy and can provide better enviromental factors for their children, and being rich can be attributed to intelligence, then over a period of time everyone will be highly intelligent and rich and the poor will cease to exist.
Evolutionary logic 101
[ 16. February 2006, 12:38: Message edited by: KBC1963 ]
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Bruce Fast
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Member # 924
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posted 16. February 2006 16:04
quote:
Bruce I have found that argument in this vein no matter how well concieved and backed never seems to go beyond the realm of philosophical conceptions.
I believe that this is why we do research. If you create an hypothesis, and if the hypothesis produces positive fruit in research then scientists feel some obligation to take notice.
You notice that I outlined a number of valid research projects. If it could be demonstrated that natural selection would prefer 6 digits over 5 in common circomstances (on snow, in water, on sand) and if it can be proven that the mutation is commonly available, then weight would be added to the validity of this hypothesis. Every bone in my body says that this must be so.
More importantly, however, the opinion of the scientific community is hardly the point. Truth, reality, is the point. Whenever the going theory doesn't correctly fit the evidence, it is the theory that is in error. Let's follow the evidence whereever it leads, rather than wasting our time trying to convince the scientific community that they are wrong or incomplete. When we lead, and when we have good evidence to lead with, they will follow.
I also think that an advantage that this line of reasoning has over other lines of reasoning is that it has a certain human appeal to do an end run around the scientific community. Average people can relate to cats. Average people can count to 5. And the basic logic here involves a very simple application of evolutionary theory.
There are a number of schools of thought growing in the ID camp, a few are (I may be missing some):
1 - Gaps. Id is frequently written of as a "god of the gaps" theory. While inventive events would leave gaps as they do in human invention, the "god of the gaps" perspective is highly ridiculed in the scientific community, partly because it says, "you can't know that."
2 - Complexity. Within complexity we see Behe's "irreduceable complexity" and Dempski's "specified complexity". Things like DNA data compression (as discussed in "The birth of MSR..." in this forum) are variants on the complexity argument. The challenge with the irreduceable complexity argument is that it "you can't get here from there" must be proven down to the single mutation event. I personally don't yet have a good grasp of "specified complexity" though the general concept is intrinsically obvious to me.
3 - Front-loading. The front-loading hypothesis is very attractive to me. If front-loading can be (reasonably) proven, I cannot see how it would not establish the viability of ID. One nice thing about the front-loading hypothesis is that it conjurs up millions of possibilities for research. However, I may be out of date, but I hardly think that there is sufficient evidenciary support yet to have front-loading considered a scientifically established theory.
4 - Patterning (that's what I am calling this pentadactilism challenge.) I believe that patterning is like front-loading in that it conjurs up lots of opportunity for research. I believe that if it can be established that nature follows pattern "over and above" random mutation + natural selection, this will make a fundimental ID case.
(I do recognize that mutation + natural selection can produce apparent patterns. For instance, it is pointed out that birds which live on isolated islands without predators often seem to loose their ability to fly. Therefore the only patterning which would produce a valid ID case would be the case where nature chooses to follow the pattern even when the opportunistic nature of m+s should be breaking the pattern.)
I also point to the incredible picture of the tree of life as rendered in cytochrome C is a classic example of patterning. To the best of my knowledge the molecular clock hypothesis is not adequate to explain this pattern.
I further point to the phenomenon of convergence as a place to be looking for 'patterning'. My understanding is that the scientific community is quite surprised at the ubiquitousness of this phenomenon. If it can be demonstrated that m+s should not produce a convergence event, then patterning will be further supported.
My simple challenge to the ID community is to recognize 'patterning' as one of the primary cases for ID.
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Irving
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posted 16. February 2006 21:44
I think 4 and 2 are the same. "Patterning" is the independent specification.
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Bruce Fast
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Member # 924
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posted 17. February 2006 12:41
quote:
I think 4 and 2 are the same. "Patterning" is the independent specification.
Hmmm, I don't see that. Certainly the test for patterning is fundimentally different than the test for either irreduceable complexity or specified complexity. Further, patterning needn't be complex, in fact patterning seems to me to be an absence of complexity, or a reduction in complexity.
To put this in a totally different way, I used to say "I don't believe that the modern synthesis is adequate to explain all of the variety of life on earth." (complexity). I now add "I don't believe that the modern synthesis is adequate to explain the lack of variety in life." (eg: the lact of 6, 7 and 8 digit creatures.)
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Bruce Fast
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Member # 924
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posted 17. February 2006 18:18
I have been considering Davison's "Precscribed Evolutionary Hypothesis." (PEH) I think that my proposed "patterning" as well as "front-loading" both fit quite nicely within the PEH framework. I believe that evidence gathered for patterning as well as for front-loading would be evidence directly supporting PEH. I do not, however, see patterning as the same thing as front-loading.
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KBC1963
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Member # 1868
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posted 17. February 2006 23:55
Bruce,
Would your definition of patterning include the peppered moth evidence where a system can specify for more than one color pattern, that in their situation allowed for selection advantage of one color or the other [depending on enviromental factors] but was unable to select out either of the paterns completely which says to me that the patterns continuously exist regardless of how selectable any one pattern may be for any length of time. [independant specification]
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Bruce Fast
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Member # 924
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posted 19. February 2006 12:52
Firstly, I think that with an hypothesis like my 'patterning' it is dangerous to over-reach, to claim that the hypothesis addresses that which it does not clearly do. I see a lot of reasons why, within the modern synthesis, multiple variants of the same creature would durably exist. Could it be, for instance, that there are more environments than just the trees that are the known haunt of the moth. Could it be that even in a clean environment, some sub-environments support the black moth in preference to the white. If so, the modern synthesis would suggest that the black moth, within that sub-environment, is preferred.
Secondly, the key that I see to find patterning is to look for a lack of variety. When variety should, according to the modern synthesis, exist but it does not, I see patterning playing it's role.
I personally have always found the peppered moth study to be painfully inconsequential. The only thing that peppered moths show is that natural selection plays a role in population balancing of existing varieties. This is hardly earth-shattering.
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Bruce Fast
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Member # 924
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posted 20. February 2006 13:54
As my first respondant on this forum, Krauze said: quote:
See Stephen Jay Gould's essay, "Eight Little Piggies" in his book of the same name."
Hah, I bumped into a web page containing the critical information from Gould's "Eight little piggies." (http://www.sjgarchive.org/library/text/b16/p0409.htm)
This actually was helpful. Though Gould would say "why 5, well, just because." He also recognizes two realities. One is that some animals, such as the giant panda, have gone out of their way to make a sixth (not a true finger as Gould clearly describes.)
More importantly, however, Gould clearly recognizes that the tanacity of pentadactilism is unexplained, that it doesn't make logical sense when he says (emphasis mine):
quote:
I should say right up front that neither of these two positions--adaptation or contingency--really address the greatest puzzle of all: the recalcitrant stability of five once it evolves. I suspect that this is a question for embryologists and geneticists; phylogenetic history may offer little in the way of clues. Why should five, once attained by whatever route and for whatever reason, be so stubbornly intractable as an upper limit thereafter--so that any lineage again evolving six or more must do so by a different path? The inquiry could not be more important, for this issue of digits is a microcosm for the grandest question of all ...
I find this quote from Gould to show simply that he has no good explanation for why 5 is so universal. Rather than try to explain it, he passes the buck to the embryologists.
I still challenge: the only way, within the modern synthesis, that 5 hasn't happened is because for some genetic reason it cannot. If, for instance, a gene that makes the five digits also is involved in creating the heart valve, then mutating to 6 would be destructive elsewhere.
Seeing as there are multiple species (at least cats and humans) with a six digit mutation and excellent health, this type of contingency hardly seems likely.
Further, Gould said, "The inquiry could not be more important." He makes this statement from the perspective of a firm belief in the modern synthesis, however. I challenge, rather, that this inquiry needs to be made from the perspective of challenging the synthesis. As I pointed out earlier, statistical studies on polydactile cats, as well as the development of a cat breed that is stabally polidactyle would prove that stable polidactilism is not a genetic impossibility. If it can happen, the modern synthesis declares that it eventually will. If it can, and if it never does, then the synthesis is in error.
Ps, Krauze, I am aware and did mention that, "the first four-limbed vertebrates were actually polydactyl."
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Bruce Fast
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posted 01. March 2006 18:30
Hmmm, my thread is stuck.
It seems that my line of reasoning is not being recognized as 'important'.
This is a twist on the usual ID argument. ID usually says, "it's too complex for natural evolution", this argument says, "it doesn't have the requisite variety for natural evolution."
I was recently reading in Mike Gene's telicthoughts.com, and came across an article: http://www.idthink.net/back/evidID/index.html
In this article the suggestion is made that the most effective proof for ID is a situation that "cannot be explained by evolution by natural selection."
I challenge you guys, explain the tenacity of pentadactilism, limiting yourselves to natural selection. I don't think it can be done! Again I remind you that Gould has described, "the recalcitrant stability of five once it evolves" as "the greatest puzzle of all," stating that, "The inquiry could not be more important." If Gould sees this issue as a big deal, maybe it is because it is a big deal. If it's not, please show me why it is not.
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John A. Davison
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posted 02. March 2006 15:21
Maybe the pentadactyl condition was established very early in vertebrate evolution as a preadaptation so that virtuosos like Franz Liszt and Vladimir Horowitz could some day dazzle us with their talent. It is of some interest that before Bach it was considered bad form to use the thumb when performing on the keyboard. It seems to me that the human hand is ideally designed for that purpose. I hope you realize that I am not kidding, not at all.
"Everything is determined... by forces over which we have no control."
Albert Einstein
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John A. Davison
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Member # 1425
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posted 03. March 2006 05:33
Bruce
Natural selection never had anything to do with organic evolution except to prevent change and thereby stabilize species long enough for them to become extinct, thereby permitting the next "prescribed" evolutionary step to occur. Organic evolution is finished and has been for a very long time. To assume otherwise is pure fantasy, something at which the Darwinians are the world's experts. They live in a world apart led by armchair gurus like Richard Dawkins, Stephen Jay Gould and Ernst Mayr, not one of whom, in my opinion, was a practicing scientist.
Scientists test hypotheses. The Darwinian hypothesis by the admission of its proponents cannot be tested. It is pure mysticism.
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Krauze
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posted 03. March 2006 11:23
Hi Bruce,
"In this article the suggestion is made that the most effective proof for ID is a situation that "cannot be explained by evolution by natural selection.""
Actually, Mike's point is that this is the requirement most often made by ID critics. He doesn't subscribe to this belief himself.
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Bruce Fast
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posted 04. March 2006 12:07
quote:
Hi Bruce,
"In this article the suggestion is made that the most effective proof for ID is a situation that "cannot be explained by evolution by natural selection.""
Actually, Mike's point is that this is the requirement most often made by ID critics. He doesn't subscribe to this belief himself.
I hope that I did not confuse by selective quoting. Mike's article very clearly shows results of a survey he did, hence other people's opinion. The logican inferrance, however, seems to be that to convince the unconvinced, as Mike is clearly in the camp of the already convinced, is ...
BTW, I have read most of the posts on Mike's idthink.net website. I find him rather insiteful.
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