Stephen E. Jones wrote:
>>SJ>One of my own web pages makes the point that
>>>Darwinism, by its own admission, requires that the laws of physics must be
>>>"deployed in a very special way":
>
>CL>Dawkins is an idiot for saying that.
>
>Why? It is true! Here is something similar from a philosopher:
What is special about the physics involved in evolutionary biology,
or Darwinism, or whatever? I've never heard it claimed that physics
was different for biochemistry. I hope you're not talking about entropy.
It isn't time yet for the annual entropy revival.
>"Granted that Nature's laws are in fact life-permitting, Darwinian accounts
>give (although usually only in very compressed form) the causal story of
>Life's evolution.... Still, not just any universe would be one in which
>Darwinian evolution would work. If a tiny reduction in the early cosmic
>expansion speed would have made everything recollapse within a fraction
>of a second while a tiny increase would quickly have yielded a universe far
>too dilute for stars to form, then such changes would (presumably) have
>been disastrous to Evolution's prospects." (Leslie J., "Universes", 1996,
>p.108).
Ah yes, the wonderful 'just-rightness' of everything. No sir, ours is not just
any old universe, our universe is super-special.
>-----------------------------------------------------------------------
>CL>You're ignoring the astronomical number of mutations that were
>>unsuccessful, that happened in the wrong order, at the wrong time,
>>to the wrong organisms, that were indeed worse than useless.
>-----------------------------------------------------------------------
>But if Cliff's " macromutations" don't do the whole job in one jump, and
>rely on survival of the fittest out of an "astronomical number of mutations
>that were unsuccessful" then it *is* Darwinian.
I have no problem with RM&NS, I do have a problem with strict gradualism.
Thus I have an ambiguous view of Darwinism. I've described possible
evolutionary mechanisms, made proposals about what happened. But why
should I care whether the proposals fit within someone's definition of
Darwinism?
>If Cliff wants to avoid the "Darwinian" aspect, he should state that his
>macromutations do the whole job, without there being an "astronomical
>number of mutations that were unsuccessful".
Why can't there be an astronomical number of unsuccessful macromutations?
It would indeed be a marvel if just one macromutation has occurred, and this
one were highly complex and successful.
>The confusion is caused by Cliff mixing up: 1) symbiosis; 2)
>macromutations; and 3) an "astronomical number of mutations that were
>unsuccessful", not to mention 4) parabiosis or "Siamese twinning". Cliff
>needs to clarify exactly how these 3 or 4 mechanisms work together to
>produce the effects that he is claiming.
#1: Symbiosis leading to integration of symbionts is a macroevolutionary
mechanism introduced by Margulis and others to explain an aspect of
cellular evolution. This mechanism may be involved in the evolution of
other aspects of cellular complexity and even metazoan complexity.
#2: The integration of separate species into one organism looks like a
macroevolutionary event to me. If one's primary interest is in genes, not
phenotypes, perhaps this sort of occurrence is no big deal, as it could
occur with little or no alteration of actual DNA sequences.
#3: An astronomical number of failures is fairly axiomatic in my
evolutionary thinking. The alternative is divine direction.
#4: Parabiosis or Siamese-twinning is a possible mechanism for the
evolution of segmentation in metazoans. Again, a minimal mutation in
the DNA is involved, but a gross change in morphology occurs.
>I presume "hand-waving" means like a magician does.
I had only read it in Gould, but I see from your quote that his colleague
uses it in the sense you specify. Like a magician, like a magic designer.
I guess the point is that if one can't fill in the details, one shouldn't
assume that they ever could be filled in; one shouldn't assume that
one's ideas are correct.
>CL>The symbiotic theory is not *my* theory. But why are symbiosis and
>>macromutation mutually exclusive? For me, the merging of symbionts *is*
>>a macromutation. My theory about segmentation uses Siamese-twinning,
>>another macromutation.
>
>Cliff is not referring to any "symbiotic theory" literature, so to date it
>appears to be Cliff's *own* theory, that he is proposing.
I accept the undeserved honor.
>And I disagree that "the merging of symbionts *is* a macromutation". No
>one AFAIK claims that symbiosis is a single event. In a previous post I
>quoted Margulis as saying the mergers took "over hundreds of millions of
>years" (Margulis L. & Sagan D., "Microcosmos," 1986, p.127).
I don't see how the genetic material of a symbiont could be gradually
integrated into that of a co-symbiont. Development, whether as a free
organism or within a combined genome, requires the presence of the
complete genome; it just seems unlikely that an organelle could be
partly generated from DNA within the cell and partly from DNA of a
partial free symbiont that is somehow enduring without part of itself.
No problem with cellular evolution taking a long time, but the process is
a series of discrete integrative macroevolutionary events.
>I agree there may be problems with Developmental Biology's Hox gene
>explanations (they are just switches which don't turn themselves on or off),
>and I agree "in segmented animals" (e.g. arthropods) "the ... trend is
>reduction...among groups of segments". The theory that arthropods
>descended from a segmented worm-like common ancestor seems plausible.
>
>But I cannot see that Cliff's "Siamese-twinning" theory adds anything to it.
>I am not saying that "Siamese-twinning" may not have played a part, but
>AFAIK Cliff has yet to produce evidence from the scientific literature that
>it has.
The evidence demands a theory that explains the sudden appearance
of segmented organisms, a theory describing a kind of evolution different
from the gradual reduction and distortion the post-Cambrian evidence
reveals. The literature seems content to blandly note the trend toward
reduction without ever being bothered thinking about the generation of
the structural complex that is being reduced and distorted.
>The only reference I have seen about parabiosis is where it was artificially
>induced and caused sterility:
There is a terminology problem. 'Siamese-twinning' is awkward. 'Parabiosis'
is obscure and hasn't been applied in evolutionary theory AFAIK. Maybe
'sudden somatic multiplication' would be better. Whatever you like.
>CL>They just did, they just happened to, through some mixup. And it caught
>>on. That's evolution. The most solid thing in favor of the symbiotic theory
>>is that it's more plausible than gradualist scenarios as a mechanism for
>>generating irreducibly complex structures.
>
>This may be Cliff's idea of a scientific explanation, but it isn't mine.
>Margulis does explain it with more detail than Cliff, but it is still sketchy
>with a lot of loose ends.
It's a difficult business. It would sure be a lot easier if I could just
think it was all designed.
>Lang B.F., Gray M.W. & Burger G., "Mitochondrial Genome Evolution
>and the Origin of Eukaryotes", Annual Review of Genetics, 1999. Vol. 33,
>pp.351-397 claim that eukaryotes and mitochondria arose together in one
>unique `big bang' event. And Forterre & Phillipe (1999) claim that the
>molecular evidence is that prokaryotes descended from eukaryotes!
What is the big deal about this? Evolution through reduction is a
familiar concept, accepted even by progressivists.
>But if the endosymbiotic theory (or indeed the other two theories) is
>correct, to me the thing that *really* needs explaining is how several
>different *bacteria*, pursuing their immediate needs, eating and being
>eaten, managed to get it *so* right, that they laid down the basic building
>blocks of all eukaryotic life (algae, plants, fungi and animals) for 2 billion
>years into the future. Margulis claims that one of these symbionts was a
>spirochetes, which is the basis of all eukaryotic nerve and brain cells:
Now it's not merely the 'just-right' theory, it's the 'just-*so*-right' theory.
I don't know how to deal with this teleological mind-set. It's alien to
evolutionary biology.
>"Or perhaps we should say that history spirals back on itself . For within
>the eye that peers through the microscope, tiny rods and cones-nerve cells
>specialized for light perception- respond to the light and to each other by
>sending chemical and electric messages along axons and dendrites-the
>fibrous arms of neurons-to the brain. Cross sections of the rod and cone
>cells in the eye reveal the 9 + 2 pattern of microtubules. The axons and
>dendrites of the brain are a differently organized mass of microtubules,
>containing all the microtubular proteins but without the 9 + 2 formation.
>Something in the eyes triggers waves of transmissions across the synapses
>between the densely packed axons and dendrites of brain cells. Riding these
>waves is the thought: "Did the spirochete motility system of the microcosm
>evolve within the ordered environment of larger organisms to become the
>basis of their nervous systems?" Proof of spirochete identity in the cells of
>the brain, beyond the rich presence in them of microtubules (neurotubules),
>is slowly accruing. Alpha and beta tubulins are the most abundant soluble
>proteins in the brain. Two or three proteins in termite-dwelling spirochetes
>have immunological similarities to tubulins in the brain and in all
>undulipodia. After maturity, brain cells never divide, nor do they move
>about. Yet we know mammal brain cells-the richest source of tubulin
>protein anywhere-do not waste their rich microtubular heritage. Rather, the
>sole function of mature brain cells, once reproduced or deployed, is to send
>signals and receive them, as if the microtubules once used for cell-whip and
>chromosomal movement had been usurped for the function of thought."
>(Margulis L. & Sagan D., "Microcosmos," 1986, p.149).
>
>If this is the case, it is more good evidence of far-sighted Intelligent
>Design. Without a theory of Intelligent Design, all naturalists can do is
>shrug their shoulders and say "They just did...it caught on. That's
>evolution".
Opportunistic evolution, utilizing structures for new functions.
>>SJ>I agree with Richard that Cliff has got hold of the problem from the wrong
>>>end. He need to have a *genetic* theory to explain *inherited* parabiosis.
>>>Twinning at the morphological level does not create one merged genome.
>>>The genome is already fixed at conception.
>
>CL>Twinning at the morphological level is a morphological phenomenon. There
>>is no merging of genomes. When this phenomenon is caused by a gene that
>>the genome of the twins has inherited, the twins' offspring will also be
>twins.
>>I don't see the problem with inheriting genes that have morphological
effects.
>>Why is a special new genetic theory needed?
>
>While twinning may be "caused by a gene", has Cliff any evidence that
>*Siamese* twinning is? The embryonic cell in its first several replications is
>not even under the control of its DNA but its cytoplasm. My understanding
>is that Siamese twinning is a non-inheritable development disorder":
I have no reason to think that developmental disorders cannot be heritable.
Of course they can be externally induced.
>>SJ>Cliff might ponder the implications of that. If Susan's more traditional
>>>Darwinist arguments are not even convincing to Cliff, and Cliff's symbiosis
>>>arguments are not convincing to other evolutionists, then that is just what
>>>would be expected if naturalistic evolution is false!
>
>CL>Just what would be expected if the topic is difficult and obscure.
>
>If "the topic" is still "difficult and obscure" after *140 years* of
>"naturalistic evolution", then that is "just what would be expected if
>naturalistic evolution is *false*"!
140 years? Evolutionary theory goes back to the beginning of literature
with the Greek naturalists, if not much further.
--Cliff Lundberg ~ San Francisco ~ 415-648-0208 ~ cliff@cab.com
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