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Topic: Phillip L. Engle: New Evolutionary Theory: The End of Ideology
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nosivad
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posted 09. May 2004 16:06
Even common descent is far from proved. I have great difficulty imagining transformations between basic body plans. I realize that while a universal intermediary metabolism clearly supports common descent, it certainly cannot be taken as absolute proof. The origin of life was for all practical purposes a miraculous event and thousands of such events are no more miraculous than one. Leo Berg, without explaining himself, postulated that there were "thousands of primary forms". As I indicated in the introduction to "Is Evolution Finished?", no one has the vaguest idea of how or how many times life originated. Like nearly everything else about evolution, we remain in the dark. The only thing I feel certain about is that it DID occur. Based on the earliest metazoon fossils I would guess there were at least a dozen independent origins. That is of course pure speculation on my part. On the other hand, if the Prescribed Evolution Hypothesis is correct, a single origin would be adequate, as all the observed diversity was prepackaged in the beginning, an idea first proposed by William Bateson and embraced by Leo Berg.
[ 09. May 2004, 16:09: Message edited by: nosivad ]
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nosivad
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posted 13. May 2004 07:52
On rereading Berg, I discovered that he actually claimed "Organisms have developed from tens of thousands of primary forms, i.e. polyphyletically." Nomogenesis page 406
However, if the Prescribed Evolutionary Hypothesis proves to be correct, as I predict it will, it will not be necessary to make such an assumption.
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Pim van Meurs
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posted 14. May 2004 12:36
Nosivad: Even common descent is far from proved. I have great difficulty imagining transformations between basic body plans.
In that context Nosivad may be interested in for instance 29+ Evidences for Macroevolution The Scientific Case for Common Descent or the transitional series between reptile and mammal
While at first the transition between reptile and mammal seems to be complicated by the fact that various skull and jaw bones seemed to have become the middle ear bones, the series shows how such a transition may have taken place. What may appear irreducibly complex at first, at closer look seems to have a beautiful explanation after all.
See also Taxonomy, Transitional Forms, and the Fossil Record by Keith B. Miller
or
HISTOLOGY OF TOOTH ATTACHMENT TISSUES IN THE LATE CRETACEOUS MOSASAURID PLATECARPUS by CALDWELL, M. W., BUDNEY, L. A., LAMOUREUX, D. O.
quote:
We present new data on the tooth attachment histology of the Late Cretaceous marine lizard Platecarpus (Mosasauridae). Examination of thin sections of a right dentary reveals the presence of a woven-fiber bone matrix that forms the margins and floor of the tooth alveolus; this bony matrix is traditionally identified as bone of attachment. We identify it as alveolar bone based on its histologic and topologic similarities to archosaurian and mammalian alveolar bone. We also identify a cribiform plate, a structure usually associated with the periodontal ligament. Parallel fibers present in multiple, non-resorbed generations of alveolar bone are tentatively identified as remnants of mineralized portions of collagen fiber bundles, or Sharpey’s fibers. Along the sides of the dentine root we identify a thin layer of acellular cementum. The acellular cementum is surrounded by an enormous mass of cellular cementum tissue that fills the alveolus. This cementum mass is composed of two histologically distinct forms: (1) a loosely organized cellular cementum ground matrix; (2) a laminar form surrounding the vascularization (cementeons) that we term osteocementum. Mosasaurs possess the attachment tissues that are used to diagnose thecodont ankylosis. Mosasaur thecodonty is derived within the Mosasauroidea (aigialosaurs + mosasaurs).
or THE MAMMAL-LIKE TEETH OF THE LATE CRETACEOUS LIZARD PENETEIUS AQUILONIUS Estes 1969(SQUAMATA, TEIIDAE) by NYDAM, RANDALL L., GAUTHIER, JACQUES A., CHIMENT, JOHN J.
There are some good papers out there showing the details of this transition.
[ 14. May 2004, 12:43: Message edited by: Pim van Meurs ]
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Scott
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posted 14. May 2004 13:55
Mammals did not evolve from reptiles. The current hypothesis is that mammals and reptiles shared a common ancestor.
quote:
These pre-mammalian groups of synapsids have at times been called "mammal-like reptiles". This term is now discouraged because although many had characteristics in common with mammals, none of them were actually reptiles.
Introduction to the Synapsida
This topic was debated at ARN, although I have to admit that there were not many (if any) defenders there of the claim that mammals evolved from reptiles.
Mammal-Like Reptiles
[ 14. May 2004, 13:56: Message edited by: Scott ]
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nosivad
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posted 14. May 2004 16:53
I have never questioned reproductive continuity. What I have questioned, along with Schindewolf and Goldschmidt in particular, is that the transformations took place gradually. This history of the fossil record is one of morphological discontinuities. Even Gould characterized the absence of intermediates as the "best kept secret of paleontology". It was no secret to Otto Schindewolf who went so far as to suggest we might as well stop looking for the missing links as they never existed. The chromosomal restructuring and release of previously contained information was an all-or-none phenomenon for which, like pregnancy, an intermediate state is inconceivable.
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Pim van Meurs
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posted 15. May 2004 12:18
Nosivad mentions Gould:
Even Gould characterized the absence of intermediates as the "best kept secret of paleontology".
Nosivad and the other readers may be interested in exploring what Gould actually said since his comments in this area have often been misunderstood.
Don Lindsay addresses this quote and compares it with other statements Gould has made to help us understand what Gould really said.
Such as
quote:
"But paleontologists have discovered several superb examples of intermediary forms and sequences, more than enough to convince any fair-minded skeptic about the reality of life's physical genealogy."
Stephen Jay Gould, Natural History, May 1994
and
quote:
"Transitional forms are generally lacking at the species level, but they are abundant between larger groups."
Stephen Jay Gould, Hen's Teeth and Horse's Toes, p.261
In A Critique of Wallace: "There are no transitional fossils" the reader is introduced to Gould and Eldredge's Punctuated Equilibrium hypothesis to help understand why they argue against the rarity of transitional fossils.
We read:
Evolution's Erratic Pace. Stephen Jay Gould. Natural History 86:14, 1977.
Gould is not saying that evolution has not occurred or that there are no transitional fossils. He is arguing for his punctuated equilibrium model to explain why we lack transitional fossils between higher taxa. Gould says:
quote:
"Our model is fully consistent with Darwin's central postulate that natural selection controls evolutionary change. Natural selection requires continuity and intermediacy, for selection must create the fit by steadily increasing the frequency of favorable variants. It does not require exceedingly slow and gradual transformations of entire populations."
Some smooth series of transitions between species have been documented.
Nosivad: I have never questioned reproductive continuity.
What Nosivad did say and to which I responded was
quote:
Even common descent is far from proved. I have great difficulty imagining transformations between basic body plans. I realize that while a universal intermediary metabolism clearly supports common descent, it certainly cannot be taken as absolute proof.
I showed that not only is common descent quite well supported by the evidence, imagining transformation between body plans may be difficult for Nosivad but nature surely seems to not have been constrained by this. Beautiful transitional series exist as I showed. Although as others have pointed out the mammal like reptile example shows how reptiles and mammals shared a common ancestor with a beautiful transitional series between them.
So while intermediate stages often may seem to be inconceivable, that does not mean that such states cannot be found and in fact as I have shown, have been found.
"Missing links" seem to have falsified Schindewald's notion.
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nosivad
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posted 15. May 2004 13:42
I learned long ago to pay no more attention to Stehen Jay Gould than I do to Richard Dawkins, both for the same reasons, reasons which I am sure I don't need to further explain. Nothing falsifies notions except hard cold facts which in this case are missing.
[ 15. May 2004, 13:44: Message edited by: nosivad ]
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Scott
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posted 15. May 2004 14:12
quote:
"Transitional forms are generally lacking at the species level, but they are abundant between larger groups."
Stephen Jay Gould, Hen's Teeth and Horse's Toes, p.261
When Gould speaks of "larger groups" here, is this just another way of saying "higher taxa"?
And yet you go on to write:
quote:
He is arguing for his punctuated equilibrium model to explain why we lack transitional fossils between higher taxa.
It seems to me then that the punctuated equilibrium model attempt to explain a non-existent phenomena. Either that, or Gould's original quote is indeed being misinterpreted. It certainly seems more in keeping with the proposal of a model to explain the absence of intermediates.
Now, back to the "mammal-like reptiles":
quote:
Although as others have pointed out the mammal like reptile example shows how reptiles and mammals shared a common ancestor with a beautiful transitional series between them.
You apparently did not read the provided material.
There is no "mammal like reptile example." There are no mammal-like reptiles. The "mammal-like reptiles" were not reptiles. The "example" fails to show how reptiles and mammals shared a common ancestor, for the "example" has nothing to do with reptiles. There is no "beautiful transitional series" between reptiles and mammals, nor between the hypothetical common ancestor of reptiles and mammals.
The idea that the evolution of mammals from reptiles is clearly shown in fossil transitionals, is simply false.
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Rex Kerr
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posted 15. May 2004 14:26
If not a transition, what is it that is shown at this link that Pim posted before?
Or, rather what is this a transition between?
[ 15. May 2004, 14:27: Message edited by: Rex Kerr ]
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Jerry D. Bauer
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posted 15. May 2004 16:05
Rex, I’m afraid that series of pictures doesn’t suggest much of anything, scientifically, IMHO.
I could put together a series of pictures of cats ranging from a kitten to a lion and suggest that the lion evolved from the kitten. That’s not much different than Lamarkianism when Lamark noted similar morphological structure between trees, and then concluded, therefore the big trees evolved from the little ones.
Speciation cannot be determined by morphology. One must either do DNA analysis or breeding experiments to determine speciation and how is one to ever go back in time and do this in the case of Therapsid?
Can you see that these examples cannot be falsified under Popperian thought and therefore shouldn‘t be used as scientific example?
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Pim van Meurs
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posted 15. May 2004 16:16
Scott: There is no "beautiful transitional series" between reptiles and mammals, nor between the hypothetical common ancestor of reptiles and mammals.
You may have missed the beautiful example I quoted
Did you read the provided materials ?
Jerry: Can you see that these examples cannot be falsified under Popperian thought and therefore shouldn‘t be used as scientific example?
On the contrary, they can be falsified but in this case they are used as a falsfication of the argument that no transitional pathway between reptiles and mammals can be envisioned when looking at for instance the origin of the inner ear bones. The fossil series shows indeed a beautiful example of such a transition. For some ways to falsify see this link
Or as the website states
"As previously stated, a succession of transitional fossils exists that link reptiles (Class Reptilia) and mammals (Class Mammalia)"
While one may argue about the correct naming of these transitions "mammal like reptiles", they do show a beautiful transition between mammals and pre-mammalian groups.
this link explains the relationship.
Another good explanation of the transitional series can be found here and here
Now add a timeline to these fossils
quote:
Figure 1.4.3. A comparison of the jawbones and ear-bones of several transitional forms in the evolution of mammals. Approximate stratigraphic ranges of the various taxa are indicated at the far left (more recent on top). The left column of jawbones shows the view of the left jawbone from the inside of the mouth. The right column is the view of the right jawbone from the right side (outside of the skull). As in Figure 1.4.1, the quadrate (mammalian anvil or incus) is in turquoise, the articular (mammalian hammer or malleus) is in yellow, and the angular (mammalian tympanic annulus) is in pink. For clarity, the teeth are not shown, and the squamosal upper jawbone is omitted (it replaces the quadrate in the mammalian jaw joint, and forms part of the jaw joint in advanced cynodonts and Morganucodon). Q = quadrate, Ar = articular, An = angular, I = incus (anvil), Ma = malleus (hammer), Ty = tympanic annulus, D = dentary. (Reproduced from Kardong 2002, pp. 274, with permission from the publisher, Copyright © 2002 McGraw-Hill)
Other well documented examples include fossil hominids and whales
Scott: It seems to me then that the punctuated equilibrium model attempt to explain a non-existent phenomena. Either that, or Gould's original quote is indeed being misinterpreted. It certainly seems more in keeping with the proposal of a model to explain the absence of intermediates.
No, the punctuated equilibrium hypothesis does explain a phenomenon, it's just that things are not black and white in real life. Not everywhere do we find beautiful transitional series and one of the explanations for this is Punctuated Equilibria
Some interesting papers
LUO Z. (1997): Transformation of the mammalian middle ear through the cynodont-mammal transition. J.Morph. 232(3): 290 Website
[ 15. May 2004, 16:33: Message edited by: Pim van Meurs ]
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nosivad
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posted 15. May 2004 17:58
Not one of the forms presented by Pim can be documented as ancestral to another. If they are in any way transitional, then why do they exhibit so many other independent features? They are so obviously different that they have been properly relegated to distinct genera. These do not represent transitional forms, but rather independent and discrete expressions which imperfectly failed to realize the mammalian ideal represented by a common dentary and three auditory ossicles. Furthermore, it is perfectly reasonable that mammals evolved polyphyletically from several reptilian sources a possibility fully in accord with my Prescribed evolutionary Hypothesis, but hardly to be expected in the Darwinian model.
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Pim van Meurs
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posted 15. May 2004 18:14
Nosivad's comments seem to add little to the discussion. When I showed evidence of transitional fossils, he rejects them without any arguments: "They are so obviously different that they have been properly relegated to distinct genera."
The idea of a mammalian ideal also would require some additional argument and data. But let's not get side tracked and instead focus on what science has presented us with namely beautiful transitions. If anyone would like to explain why these fossils fail to provide for such evidence then I am definitely interested in such a conversation.
The data speak for themselves, the transitional sequence showing the evolution of the mammalian inner ear from jawbones is well described by these fossil sequences.
My contribution was to explain why one should be careful to quote Gould in support of absence of transitional sequences especially in light of the beautiful sequences presented here as well as the many more available to us for inspection.. In addition I provided further evidence that shows the fact of common descent.
As far as 'none of these forms can be documented as ancestral' misses the point.
Perhaps Nosivad can start a thread where he explores and expands his belief that "Furthermore, it is perfectly reasonable that mammals evolved polyphyletically from several reptilian sources a possibility fully in accord with my Prescribed evolutionary Hypothesis, but hardly to be expected in the Darwinian model."
I would certainly be interested in seeing Nosivad present us a comparisson between what the Darwinian model would expect and what the prescribed evolutionary hypothesis would expect.
A helpful paper on In quest for a phylogeny of Mesozoic mammals may help understand how science addresses phylogenetics.
as well as the following paper
Luo, Z.-X., A. W. Crompton and A-L. Sun. 2001. A new mammaliaform from the Early Jurassic of China and evolution of mammalian characteristics. Science 292: 1535-1540
quote:
A fossil from the Early Jurassic (Sinemurian,;195 million years ago) represents
a new lineage of mammaliaforms, the extinct groups more closely related to the living mammals than to nonmammaliaform cynodonts. It has an enlarged cranial cavity, but no postdentary trough on the mandible, indicating separation of the middle ear bones from the mandible. This extends the earliest record of hese crucial mammalian features by some 45 million years and suggests that separation of the middle ear bones from the mandible and the expanded brain vault could be correlated. It shows that several key mammalian evolutionary innovations in the ear region, the temporomandibular joint, and the brain vault evolved incrementally through mammaliaform evolution and long before the differentiation of the living mammal groups. With an estimated body weight of only 2 grams, its coexistence with other larger mammaliaforms with similar triconodont-like teeth for insectivory within the same fauna suggests a great trophic diversity within the mammaliaform insectivore feeding guild, as inferred from the range of body sizes.
Zhe-Xi Luo has researched these evolutionary relationships and concludes
quote:
Evolutionary Origins of the Mammalian Middle and Inner Ears
Homology of the mammalian middle-ear ossicles with accessory jaw bones on the mandible of other vertebrates is a classic example of comparative anatomy and vertebrate evolution. Previously it was not clear how the accessory mandibular (postdentary) bones of cynodonts (close relatives to mammals) could migrate from the mandible to the cranium in mammals. Luo and Crompton (1994) show that the phylogenetic transformations of several features of the quadrate (incus) made it possible for the postdentary bones to establish new sites of attachment to the cranium. Through the cynodont–mammal transition, the simple changes in the quadrate and its surrounding structures have allowed a fundamental reorganization of the basicranium while a presumably functional tympanum was maintained in the mandible. New data from Luo and Crompton (1994) support Allin and Hopson’s (1992) hypothesis on the postdentary origin of the mammalian tympanic membrane.
Recent data appears to be supporting early scenarios making this transition one of the better documented and tested transitions.
Check out for instance
A newsymmetrodontmammal from China and its implications for mammalian evolution
Yaoming Hu, Yuanqing Wang, Zhexi Luo & Chuankui Li NATURE VOL 390 13 NOVEMBER 1997
or
A new mammaliaform from the early Jurassic and evolution of mammalian characteristics. Luo ZX, Crompton AW, Sun AL. Science. 2001 May 25;292(5521):1535-40.
quote:
A fossil from the Early Jurassic (Sinemurian, approximately 195 million years ago) represents a new lineage of mammaliaforms, the extinct groups more closely related to the living mammals than to nonmammaliaform cynodonts. It has an enlarged cranial cavity, but no postdentary trough on the mandible, indicating separation of the middle ear bones from the mandible. This extends the earliest record of these crucial mammalian features by some 45 million years and suggests that separation of the middle ear bones from the mandible and the expanded brain vault could be correlated. It shows that several key mammalian evolutionary innovations in the ear region, the temporomandibular joint, and the brain vault evolved incrementally through mammaliaform evolution and long before the differentiation of the living mammal groups. With an estimated body weight of only 2 grams, its coexistence with other larger mammaliaforms with similar "triconodont-like" teeth for insectivory within the same fauna suggests a great trophic diversity within the mammaliaform insectivore feeding guild, as inferred from the range of body sizes.
[ 15. May 2004, 18:42: Message edited by: Pim van Meurs ]
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Scott
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posted 15. May 2004 19:38
quote:
You may have missed the beautiful example I quoted...
No, I didn't miss it. It is in fact what led me to research the subject for myself, rather than take it on faith.
Your "beautiful example" is titled:
Skulls and jaws of synapsid reptiles and mammals.
I don't know how much clearer I can make this, and I really hate repeating myself, but ...
SYNAPSIDS ARE NOT REPTILES!
There is no such entity as a "synapsid reptile." Even the nice cladogram that you posted makes this fact clear.
quote:
Or as the website states
"As previously stated, a succession of transitional fossils exists that link reptiles (Class Reptilia) and mammals (Class Mammalia)"
My point is that the website is wrong. Quoting the website as evidence that the website is correct is an interesting response, but unconvincing.
Precisely within which group within Class Reptilia is this "succession of transitional fossils" found? It most certainly is not the Synapsids, for the Synapsids are not within Class Reptilia.
Neither are the Synapsids the common ancestor of the reptiles and the mammals. The "transitionals" within the Synapsids fail to provide the "beautiful transitional series" between reptiles and mammals, and they also fail to provide the "beautiful transitional series" between the hypothetical common ancestor and either reptiles or mammals.
quote:
While one may argue about the correct naming of these transitions "mammal like reptiles" ...
Only if one wishes to be obtuse in the face of all evidence to the contrary. "Mammal-Like Reptiles" is a complete misnomer. Now you know better.
quote:
Figure 1.4.3. A comparison of the jawbones and ear-bones of several transitional forms in the evolution of mammals.
Precisely. The evolution of mammals. Not the evolution of reptiles. Not the evolution of reptiles to mammals. Not the evolution of mammal-like reptiles to mammals.
You wrote:
quote:
Nosivad may be interested in for instance 29+ Evidences for Macroevolution The Scientific Case for Common Descent or the transitional series between reptile and mammal...
While at first the transition between reptile and mammal...
There is no such "transitional series," or if there is, it's not to be found in the Synapsids. Perhaps you know of some other that you could present? If not, please admit you were wrong about this and retract the claim that novisad could find the evidence he was looking for in "the transitional series between reptile and mammal." It's not there.
p.s. novisad is talking about "basic body plans" and you are talking about inner ear bones. Seems to be a bit of a disconnect there as well.
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Rex Kerr
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posted 15. May 2004 20:26
I think the disagreement here arises from a difference between the common terminology "reptile" and the scientific taxonomic classification of "member of Class Reptilia".
There isn't a smooth transition between Class Reptilia and Class Mammalia because Class Mammalia is not a monophyletic subset of Class Reptilia.
What the transitional fossils do show is a transition between earlier synapsids, which morphologically were reptile-like, and mammals.
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