|
Author
|
Topic: Speciation
|
RBH
Member
Member # 380
|
posted 26. April 2004 12:57
Rex Kerr wrote quote:
RBH's estimates are useful, but they're off by a factor of 1000. 4 trillion species ever / 3.5 billion years = ~800 species/year, at the high end of the estimate.
He's right: I misplaced a decimal point in setting up the calculations and that infected all the estimates. That's embarrassing. I apologize.
RBH
[ 26. April 2004, 13:27: Message edited by: RBH ]
IP: Logged
|
|
Pim van Meurs
Member
Member # 541
|
posted 26. April 2004 13:15
Nosivad: "So Darwinian theory seems to be doing quite well it seems." This statement by Pim I find utterly unbelievable.
I understand your feelings about these matters and since they lack in much supporting evidence I find them neither surprising nor really relevant. Instead I am focusing on your unsubstantiated claims that speciation has stopped, although you seem to be shifting to speciation may still be happening but not through Darwinian pathways. It's progress but given the amount of evidence provided I find such a position hard to take seriously.
Darwinian theory, despite its many shortcomings remains as solid as it was when it was first presented. In fact many recent findings strengthen the theory. For instance the findings of scale free networks in RNA and proteins, the findings that neutrality is both essential for robustness and evolvability, the findings based on genome wide evidence.
Of course much of this was not known in the early 20th century.
IP: Logged
|
|
warren_bergerson
Member
Member # 262
|
posted 26. April 2004 14:15
Rex raises the interesting question of the human impact on speciation. His suggestion that rates of speciation for the standard model depend on the number of niches available suggests that the standard model is purposeful (speciation occurs in order to fill an available niche).
Maybe I wasn’t clear on this point, but speciation based on purposeful intelligence suggests or predicts that in most instances ‘adaptive change without speciation’ is generally a better choice than ‘adaptive change with speciation’. Speciation, I suggest, is only likely to occur when two different adaptive forms remain in close physical proximity where interbreeding is likely to result in non-adaptive intermediate forms. Adaptive change being separate from speciation, I suggest, explains why selective breeding which producing significant changes in form does not appear to produce speciation.
Note that if there are two features A and B both of which have some positive benefits, the ‘intelligent choice’ in most instances is ‘A and B’ rather than either ‘A’ or ‘B’. One of the reasons humans have had such a major impact is that we have been able to occupy and dominate so many different niches with essentially no physical or genetic changes. Humans have the ability to select “A and B and C and ….”.
It is reasonable to predict that in the very near future humans will discover how to design and implement artificial species boundaries. Once discover how to design new species, the net impact of humans will likely be to increase the number of species.
IP: Logged
|
|
Janitor@MIT
Member
Member # 125
|
posted 26. April 2004 14:44
Kondrashev writes (in a review of "Frogs, Flies, and Dandelions: The Making of Species" by Menno Schilthuizen. ) that “we are witnessing the Darwinian restoration (TRENDS in Ecology & Evolution Vol.16 No.7 July 2001).” (With a nice little glossary—longer than the review!) and Mallet concurs, “An extraordinary feature of the current revolution is the strength of rapprochement with Darwin's own views (J . EVOL. BIOL. 14 (2001 ) 887-888. 2001 BLACKWELL SCIENCE LTD).”
Kondrashev, “Better still, the book sets straight the record distorted by the so-called ‘Modern Synthesis’. As anybody who bothers to read ‘The Origin of Species’ (Chapter 4) can see, Darwin treated speciation in depth and believed that it is driven by natural selection caused by competition between sympatric organisms. However, in the middle of the last century it somehow became widely accepted (a) that Darwin did not understand the origin of species; (b) that sympatric speciation does not happen; and (c) that the driving force behind speciation is genetic drift, because the key stage of the process is counteradaptive. One might think that such abuse should be reserved for those Russians who commit all their thoughts to the pages of Siberian Ecological Journal (http://www-psb.adsbras.nsc.ru/ secjw.htm) – an interesting journal, if only you could read it,”
Mallet also agrees that this rehabilitation of Darwin is a repudiation of the Neo-Darwinists. Mallet is philosophical about this ~60 year long Neo-Darwinian distraction. You don’t know a dead end is a dead end until you explore it.
Nonetheless, the central problem for Darwin appears to remain outstanding—just what is the elementary unit of evolution? (If there is such a thing.) Seems to me that the individual is the only concrete entity that biologists treat. (I seem to be conventionally "Darwinian" about this. But many disagree with me, e.g., Mayr and Hull, who insist, upon some questionable hermenuetics and historiography, that Darwin was the first "population biologist.) But how can you have an evolutionary theory about individuals? (I think its all about individualsand populations are only secondary.)
I was recently attempting to unearth any information about George Price (not much luck, any help would be appreciated), but somehow got diverted down a path and was momentarily distracted by an argument between Roberta Millikan and Robert Brandon (each with their own choruses, Denis Walsh, Phillip Kitcher, Susan Oyama, Richard Lewontin, Alex Rosenberg, et al).
I found it difficult to relate to categories like “determinism” and “indeterminism” because they seem to have been antiquated in the very field (physics) from which the biologists borrowed them.
But I remember once having a lengthy argument over whether design was deterministic or indeterministic, w/o making much headway, and eventually withdrawing from the discussion when the “gamesmanship” began. And I don’t think there is any substantive formal distinctions that can maintained here (!).
The basic argument I made was that “novelty” or the possibility of “discovery” are excluded on conventional notions of “determinism.” So there appears to be a fundamental conceptual barrier here in evolutionary thought (due to… who?), as novelty and discovery (Whatever they are!) seem to be instantiated in the individual, whereas thinking about “individuals” rather than “populations” (of individuals?) was is (strangely?) resisted.
“Novelty” and “discovery” seem to require to treat individuality rather than dissolve it in vague notions of “population,” or “species,” or other categories that are inclusive only by excluding the obvious—the individual. But how can one have a “science” all of whose outcomes are unique! Only with some considerable difficulty, I’d say.
(Both the articles are posted to the Web, but I’m too lazy to look for them.)
IP: Logged
|
|
nosivad
Member
Member # 767
|
posted 26. April 2004 17:45
Every genetic change which was destined to be inherited must have taken place in a particular cell in the germinal line of an individual organism. Accordingly, population genetics has absolutely nothing to do with the origin of genetic change (evolution). Population genetics deals only with the subsequent fate of such heritable changes. Somehow the notion has become established that populations are what have evolved. That is simply not true. Also, since all genetic changes are instantaneous events, so all of evolution has, in my view, been instantaneous. Indeed that is the basis of my paper "The Case for Instant Evolution". There is no place for gradualism in either genetic or evolutionary change. As Schindewolf correctly observed, we might as well stop looking for the missing links as they never existed. This perspective will suddenly become acceptable if one will simply accept Goldschmidt's considered judgement that it is the chromosome, not the gene, that was the unit of evolutionary change. Furthermore, there is no convincing evidence that the accumulation of base pair substitutions had anything whatsoever to do with either speciation or the evolution of any of the higher taxonomic categories. Please note my deliberate use of the past tense.
IP: Logged
|
|
warren_bergerson
Member
Member # 262
|
posted 27. April 2004 07:46
The purpose of this thread was to introduce a type or class of scientific hypotheses based on the concept of ‘speciation controlled by purposeful intelligence’. This type or class of hypotheses is part of larger class of ‘… controlled by purposeful intelligence’ hypotheses which includes ‘evolution controlled by purposeful intelligence’, ‘adaptive behavior controlled by purposeful intelligence’, ‘animal behavior controlled by purposeful intelligence’, and ‘robots controlled by purposeful intelligence’ and ‘human behavior controlled by purposeful intelligence’. All the predictive scientific hypotheses in this class rely on what is called intelligent teleological determinisms.
As stated earlier, the introduction of hypotheses based on purposeful intelligence raises two basic questions: 1) Are these hypotheses scientifically sound and thus permissible for use in scientific analysis? And 2) Can these hypotheses produce useful, reliable, and testable hypotheses?
I hope from the discussion here I have been able to provide at least a taste of the types of predictions and interpretations of data that can be formulated using the controlled by purposeful intelligence. Clearly, and as would be reasonably expected, most supporters of conventional approaches to formulating scientific theories reject the proposed approach with the usual hand wave.
As a final thought on this subject, I suggest you consider the form or nature of the species boundary. Some traditional hypotheses might expect or predict that all species boundaries (the physical and chemical factors which prevent members of two species from successfully inter-breeding) would be build of the same material. Purposeful intelligence, by contrast, suggests that species boundaries are a concept or design intended to serve a purpose. These concepts or designs can be and are constructed from any material that is available, convenient and effective. Thus, purposeful intelligence hypotheses would predict that different species boundaries may involve very different physical or chemical structures. What is important is the ‘intelligent design’ and functionality of the boundary, not the specific physical composition.
IP: Logged
|
|
nosivad
Member
Member # 767
|
posted 27. April 2004 14:31
Pim
I am very intrigued by your comment -"Darwinian theory, despite its many shortcomings remains as solid as it was when it was first proposed".
I cannot imagine an hypothesis (I will not dignify it with the word theory) with many shortcomings being regarded as "solid". Here is a fundamental one which was exposed by St. George Jackson Mivart in Darwin's own day. There is no conceivable way that Natural Selection, that cornerstone of Darwinism, can possibly have been involved in the origin of new structures such as legs, wings, eyes, ears, or, in short, any other structure not present in an ancestral form lacking such features. Lamarck had already anticipated this difficulty and ascribed such new structures as resulting from an "inner need". I am sure we can agree that Lamarck's explanation is unacceptable even though it seems logically inescapable when compared with the Darwinian alternative. This dilemma has led me to the Prescribed Evolutionary Hypothesis which postulates that the necessary information for the evolution of novel structures was somehow encapsulated in latent form in our evolutionary ancestor or ancestors. There is nothing radically new in this suggestion as its independently conceived origins can be traced to William Bateson, Leo Berg and Pierre Grasse as I have indicated in earlier posts. I am convinced, with them, that evolution proceeded according to definite laws, a view which is obviously anathema to a doctrinaire Darwinian such as yourself.
I know of no one who would deny that Mathematics, Physics and Chemistry all are governed by prescribed laws which are totally independent of the human condition. Why must any evolutionist deny even the possibility that such laws have operated in determining evolutionary progress? I personally believe that the Prescribed Evolutionary Hypothesis represents the only possible explanation for what remains the great mystery of organic evolution. In any event, since you have admitted that Darwinian theory has many shortcomings, I now ask - what are some of the others?
[ 27. April 2004, 16:41: Message edited by: nosivad ]
IP: Logged
|
|
RBH
Member
Member # 380
|
posted 27. April 2004 16:52
nosivad wrote quote:
Here is a fundamental one which was exposed by St George Mivart in Darwin's own day. There is no conceivable way that Natural Selection, that cornerstone of Darwinism, can possibly have been involved in the origin of new structures such as legs, wings, eyes, ears, or, in short, any other structure not present in an ancestral form lacking such features.
Gosh. Is this fellow just wasting his time, then? quote:
The past decade has seen a revolution in our understanding of the origin of tetrapods (limbed vertebrates), with new fossil discoveries, the re-analysis of known taxa, and the application of cladistic methodology coming together to produce a much clearer picture of this major evolutionary event. At the same time, rapid advances in developmental genetics have begun to uncover the genetic patterning underlying tetrapod structures such as limbs. By bringing together these separate data sets in a phylogenetic context, it is possible to begin drawing tentative conclusions about the evolutionary changes in gene expression patterns that accompanied the origin of tetrapods.
Did St. George Mivart, not having access to the last 150 years of genetics, cladistics, paleontology, and molecular biology, have the final word in spite of that?
I notice in nosivad a marked tendency to cite long-dead authorities as though they were still authoritative, and to elide a good deal of actual research. I also note a marked tendency to elide specifics in his own work, as when he says "This dilemma has led me to the Prescribed Evolutionary Hypothesis which postulates that the necessary information for the evolution of novel structures was somehow encapsulated in latent form in our evolutionary ancestor or ancestors." I see in Davidson's assertion and "Manifesto" no indication of how the "somehow" is actually implemented, no description of what "latent" means of "encapsulation" are/were, nor an indication of how the "encapsulated" information avoided the ravages of thermodynamics through some billions of years until those novel structures finally appeared, in the absence of continuing selection for conservation of the unexpressed latent "information." I see no actual theory, in other words, just another label.
RBH
IP: Logged
|
|
Janitor@MIT
Member
Member # 125
|
posted 27. April 2004 19:14
I often cite extinct authorities, such as Charles Darwin. (I’ve even argued that Mivart is to be preferred to Darwin!) That they share the common fate, not just extinction but antiquation, must be what RBH is highlighting.
Dr. Davison can answer for himself, but I see no real problems in anything RBH has to say. If they are problems they are problems for evolutionary biology. How can I say that I am related to some ancestor existing billions of years ago if the ravages of time (thermodynamics) are expected to erase all traces of such a connection? Should I consider such information, the connection, as being latent or virtual, or whatever?—even assuming such information exists.
Evolution is a highly conservative process and we rely on that fact to make such inferences, which are no less problematic than “design inferences,” which also rely on that fact.
What is most interesting about this process is exactly what is conserved over large intervals. It’s not any specific sequence (a failure of Dr. Dembski). It is the “virtual” or “latent” information, which biologists are beginning to recognize. What is it?
Otherwise, I am not defending nosivad.
IP: Logged
|
|
Pim van Meurs
Member
Member # 541
|
posted 27. April 2004 19:49
Nosivad: I am very intrigued by your comment -"Darwinian theory, despite its many shortcomings remains as solid as it was when it was first proposed".
I cannot imagine an hypothesis (I will not dignify it with the word theory) with many shortcomings being regarded as "solid".
That depends on the shortcomings now wouldn't it? Some of the shortcomings of Darwinian theory include the absence of an understanding of DNA as the inheritable material for instance. However such shortcomings hardly undermine the validity of Darwinian theory which is relatively simple and elegant namely variation and selection.
Darwin's understanding of evolutionary theory and his access to data was quite limited as compared to present day.
I still see no attempt by Nosivad to provide any support for his claims.
Nosivad further muddles the issues by making the following strawman argument
quote:
I am convinced, with them, that evolution proceeded according to definite laws, a view which is obviously anathema to a doctrinaire Darwinian such as yourself.
I am neither a doctrinaire Darwinian nor do I reject the notion that natural laws do guide evolution to a certain extent. Michael Ruse has an excellent and recent book written on this topic. Nosivad may be interested in reading how modern science looks at evolutionary theory.
I am still waiting however for Nosivad to back up his claims. Appeal to ignorance such as
"There is no conceivable way that Natural Selection, that cornerstone of Darwinism, can possibly have been involved in the origin of new structures such as legs, wings, eyes, ears, or, in short, any other structure not present in an ancestral form lacking such features."
are not very helpful either, especially since plausible evolutionary pathways have been provided. Heck even the transitional sequence from Reptile to Mammal shows how the inner ear structures arose.
[ 27. April 2004, 19:55: Message edited by: Pim van Meurs ]
IP: Logged
|
|
nosivad
Member
Member # 767
|
posted 27. April 2004 20:09
Per Alberg's summary completely supports the Prescribed Evolutionary Hypothesis. As Alberg himself indicates, it is the changes in GENE EXPRESSION that have characterized evolutionary change. The genes themselves have apparently remained relatively constant, an assumption entirely in accord with what we know about the great antiquity of many gene families. In other words, it completely supports the Prescribed Evolutionary Hypothesis. Furthermore, Alberg's piece does not even suggest that Natural Selection was even involved, which is the heart of the Darwinian scheme and was the object of Mivart's cogent criticism. My reference to my predecessors is to establish their priority in long ago recognizing the transparent absurdity of the Darwinian model, in Mivart's case during Darwin's own lifetime. Actually the situation for Darwinism today is much worse than it was in the nineteenth century when so little was known of the enormous complexity of the living system, a complexity that could never have arisen by chance.
The simple truth is that Darwinism does not even qualify as an hypothesis since it, by definition, has absolutely no predictive value, a feature which every hypothesis must have.
Incidentally, in the year of his death (1900), Mivart, a Roman Catholic, was excommunicated because of his disagreements with Catholic dogma. More recently, Goldschmidt, Grasse, Bateson, Berg, Broom, Schindewolf and many others including myself have similarly been excommunicated from the monolithic evolutionary establishment because of their disagreements with Darwinian dogma.
Transitional sequences certainly do not show HOW structures arose at all. All that they show is THAT they arose. I am convinced that their final and irreversible states were preprogrammed and ultimately predestined. If anyone wants to continue to believe that everything we see has resulted from chance, please be considerate enough to allow me to believe otherwise.
[ 28. April 2004, 01:36: Message edited by: nosivad ]
IP: Logged
|
|
RBH
Member
Member # 380
|
posted 27. April 2004 21:53
J@MIT wrote quote:
... I see no real problems in anything RBH has to say. If they are problems they are problems for evolutionary biology. How can I say that I am related to some ancestor existing billions of years ago if the ravages of time (thermodynamics) are expected to erase all traces of such a connection? Should I consider such information, the connection, as being latent or virtual, or whatever??even assuming such information exists.
Evolution is a highly conservative process and we rely on that fact to make such inferences, which are no less problematic than "design inferences," which also rely on that fact.
The nature of the problem is different for evolutionary biology. There one must account for the indications (genetic, say) that you are related to some billion-years ago ancestor. Those indications are patterns embodied in a medium that are actively selected and maintained in the far-from-equilbrium systems that are biological organisms. There are immediate consequences for organisms that don't maintain, say, the conserved APTase domain: they die.
For any front-loading scheme that supposes that all the necessary "information" (always left vague and fuzzy) was somehow encapsulated and held latent until needed to grow limbs, say, the problem is the preservation of that latent information in the absence of active selection for its preservation over billions of years of thermodynamic insults.
J@MIT asked quote:
What is most interesting about this process is exactly what is conserved over large intervals. It?s not any specific sequence (a failure of Dr. Dembski). It is the "virtual" or "latent" information, which biologists are beginning to recognize. What is it?
I'm not sure what the difference between "latent" and "virtual" J@MIT is invoking actually is.
nosivad: You're quite free to believe whatever you wish. I have no stake at all in your beliefs.
RBH
Added in late edit: nosivad wrote quote:
Incidentally, in the year of his death (1900), Mivart, a Roman Catholic, was excommunicated because of his disagreements with Catholic dogma.
And was originally buried in unconsecrated ground. Later, though, he was rehabbed (the being plea that his late anti-Church writings were due to illness-induced insanity) and he was posthumously reinstated. Or recommunicated. Or whatever the term is.
[ 27. April 2004, 23:10: Message edited by: RBH ]
IP: Logged
|
|
nosivad
Member
Member # 767
|
posted 28. April 2004 02:08
Of course Mivart was insane. He had challenged and exposed both Darwinism and Church Dogma. I am guilty of the same heinous crime. I have already had my competence questioned by a member of this board. It comes with the territory. We antiDarwinians are all demented. As for my several predecessors on whom I have so heavily relied, I recommend the bibliography and text of Gould's opus magnus, "The Structure of Evolutionary Theory". There you will find them conspicuously missing or misrepresented. Incidentally, there is no evolutionary theory. There are only failed or untested hypotheses of which the semi-meiotic hypothesis is one of the latter. I no longer wonder why.
"Silence is the most perfect expression of scorn"
George Bernard Shaw
[ 28. April 2004, 02:13: Message edited by: nosivad ]
IP: Logged
|
|
Pim van Meurs
Member
Member # 541
|
posted 28. April 2004 15:14
Nosivad: Transitional sequences certainly do not show HOW structures arose at all. All that they show is THAT they arose. I am convinced that their final and irreversible states were preprogrammed and ultimately predestined. If anyone wants to continue to believe that everything we see has resulted from chance, please be considerate enough to allow me to believe otherwise.
But as I and others have already shown, it's not a claim that 'everything we see has resulted from chance'. Such a fallacious portrayal of Darwinian theory may help understand why you feel that you have to reject it.
Transitional fossils help understand what happened, that you believe that it was 'inevitable' surely could benefit from some supporting evidence. How would you go about this I wonder?
But it also shows that your claim that 'there is no conceivable way that Natural Selection, that cornerstone of Darwinism, can possibly have been involved in the origin of new structures such as legs, wings, eyes, ears, or, in short, any other structure not present in an ancestral form lacking such features." is wrong. There are conceivable ways after all.
Some wonderful examples exist of hox genes and fish transitions, eye transitions. The existence of such intermediaries surely seem to contradict the one swoop transition ideas.
That science has found these transitional fossils between mammals and reptiles merely is one of the many supporting evidences of evolutionary theory.
Our understanding of evolution of limbs, which you argue cannot be explained by (Darwinian) evolutionary theory, seems to also contradict your claims.
In addition, scientists have 'conceived' of a Darwinian pathway for the evolution of the eye. Nillson and Pelger in "A Pessimistic Estimate Of The Time Required For An Eye To Evolve" Proceedings of the Royal Society London B, 1994, 256, pp. 53-58 for instance.
quote:
Theoretical considerations of eye design allow us to find routes along which the optical structures of eyes may have evolved. If selection constantly favours an increase in the amount of detectable spatial information, a light-sensitive patch will gradually turn into a focused lens eye through continuous small improvements of design. An upper limit for the number of generations required for the complete transformation can be calculated with a minimum of assumptions. Even with a consistently pessimistic approach the time required becomes amazingly short: only a few hundred thousand years.
Same for wing evolution
Brain Behav Evol. 1997 Jul;50(1):13-24. The evolution of insect wings and their sensory apparatus. Dickinson MH, Hannaford S, Palka J.
quote:
The development of wings has undoubtedly played a major role in the enormous diversification of insects. New insights into the evolutionary history of insect wings are available from paleontological, physiological and biomechanical studies. A recent hypothesis, derived primarily from paleontological evidence, is that wings arose from leg exites, small flaps associated with proximal leg segments. We present data from studies on physical models that are consistent with this hypothesis. The exites would have been moveable, and measurements on scaled models show that they would have generated aerodynamic lift by unsteady mechanisms associated with vortex shedding. An examination of the sensory structures found on insect wings is also consistent with the interpretation of protowings as leg exites. In addition to mechanosensory bristles, such as are found all over the body, the wings of modern insects carry campaniform sensilla sensitive to cuticular deformation and contact chemoreceptors whose stimulation elicits a feeding response. Both classes of receptors are also found on the legs of modern insects but not on the thorax, favoring the leg exite theory.
See also Developmental Basis of Limb Evolution by J. RICHARD HINCHLIFFE in Int. J. Dev. Biol. 46: 835-845 (2002)
[ 28. April 2004, 15:20: Message edited by: Pim van Meurs ]
IP: Logged
|
|
|
|
|
Topic Closed
Printer-friendly view of this topic
