Thursday, January 17, 2013

Which subjects need to be added to current evolutionary theory to create a new extended synthesis?

Here's a list of subjects that have been proposed as extensions to the so-called "Modern Synthesis" of evolution. Some of them are radical changes and others are more subtle.

I'm not going to explain all of them because that would take many posts and a lot of time. Besides, most of them have been openly debated on numerous blogs over the past decade or so.

Choose the one(s) that you think are the most important.



36 comments :

  1. It's not clear to me what the benefit would be of designating topics for an 'extended synthesis'. There are real scientists working on most of them (save for theistic evolution - Lamarckian evolution may actually have a place, which is another post), but I am confused as to what it means that they be important. Are you asking your readers to evaluate how much they mean for evolution, or what?

    ReplyDelete
    Replies
    1. Have you read "Evolution: The Extended Synthesis"? It's a summary of the "Altenberg 16" meeting. This group thinks that current evolutionary theory is insufficient and needs serious updating. The words "paradigm shift" and "revolution" come up frequently in these debates.

      Delete
    2. Yes I have. And I spoke with Pigliucci about it when he visited MSU a while ago. However, it is still not clear to me what the question you are asking is. Are we to vote for topics that we think are definitely influencing evolution sometimes? Ot just perhaps of occasional minor relevance? Or major drivers all the time?

      The thing is, even if some of those topics are listed as part of an extended synthesis, the others are still going to be worked on, and will still be of relevance on occasion. What does it matter whether we designate topics for an extended synthesis? All that matters is that people work on them, and show them to be relevant or not.

      Delete
    3. It's a paradigm shift, see. That's what you say when you don't have a well-defined theory that makes testable predictions confirmed by observation. Paradigm shift.

      Vitalism. Vital force. Paradigm shift.

      Orthogenetic evolution. Paradigm shift.

      Spiritualism. Seances. Ouija board. Paradigm shift, see.

      Near-Death Experiences. Somebody gets brain damage, sees a spook. Michael Egnor will tell you that if you don't believe brain-damaged people when they say they talked to a spook when their brain was deprived of oxygen, well you're against the paradigm shift.

      If you're against the paradigm shift, why you're an old codger.

      James Shapiro, who's old enough to be my Dad, wrote a whole blog post attacking me as an old codger, I'm closed-minded see, because I pointed out that Shapiro's hypothesis of "natural genetic engineering" was about as testable as, oh, the "vital force" that makes amoeba move, or "orthogenetic evolution."

      I'm opposed to the new paradigm, or as Ronald Reagan pronounced it, paradiggum.

      Forward to the twelfth century!

      Delete
  2. Oops, did see "Natural Genetic Engineering" first time around. I voted for everything but that and theistic evolution, because there are serious researchers working on all the rest.

    ReplyDelete
  3. How about Hologenome Theory? That is in fact what I was referring to when I said Larmarckian evolution has a place.

    ReplyDelete
  4. The four I voted for seem to be everyone's favourites so far, so just to be more original... haven't you forgotten Intelligent Design?

    ...

    I'll get me coat.

    ReplyDelete
    Replies
    1. That might be covered under the EvoTheo option near the bottom...;)

      Delete
    2. "Intelligent Design?" If it were so, shouldn't I have three hands?

      Delete
  5. I'm finding this hard to understand. From what I can tell, the ones I would vote on (e.g. EvoDevo, convergence) are more or less part of current orthodoxy, though not of the Modern Synthesis c. 1950. The ones I wouldn't vote on are either way overblown (e.g. epigenetics), probably unimportant (e.g. group selection), or full-tilt wacko (e.g. symbiogenesis, theistic evolution).

    What is mutationism? Facilitated variation?

    ReplyDelete
    Replies
    1. I was using the term "Modern Synthesis" to refer to standard, orthodox, evolutionary theory based on population genetics. Some people prefer to reserve the term for the hardened version of the Modern Synthesis that took over after 1959. If that's what you mean then random genetic drift and Neutral Theory would have to be added.

      I agree with you that EvoDevo does not conflict with modern evolutionary theory and, thus, it is not going to be part of an extended synthesis.

      Mutationism is the view that mutations play an important role in directing the paths that evolving lineages take. The modern view was explained by Arlin Stoltzfus in a series of guest posts on Sandwalk: Mutationism. I agree with Arlin and that's why I voted for mutationism.

      Facilitated variation is the view described by Kirschner and Gerhart in their book The Plausibility of Life. It's mostly irrelevant.

      Delete
  6. Along with the things to be added, I vote to fix serious problems in the existing synthesis, especially regarding the factors controlling the evolution of genetic divergence between demes. These problems arise due to misinterpretation of "differentiation" measures in population genetics.

    ReplyDelete
    Replies
    1. Not sure why that got published as "Unknown". I wasn't trying to be anonymous.
      Lou Jost

      Delete
  7. At least two of those things, convergence and contingency, seem to me to be entirely compatible with the Modern Synthesis (indeed, convergence would seem to be inherent in it). I'll admit, I'm not an historical expert, so I don't know whether the authors of the Synthesis themselves would have seen it that way.

    full-tilt wacko (e.g. symbiogenesis

    The term 'symbiogenesis' as originally coined refers to something that has become standard orthodoxy: the origin of at least some eukaryotic organelles from symbiotic prokaryotes. The process's most famous proponent, Lynn Margulis, did (I think) go off the deep end in how extensively she tried to apply the principle. And Donald Williamson is something else entirely.

    What is mutationism? Facilitated variation?

    Basically, 'mutationism' is the principle that selection is overshadowed as a moulding force in evolution by the question of just which mutations happened when.

    ReplyDelete
    Replies
    1. Symbiogenesis: note the parenthetical explanation -- speciation by acquiring genomes. This is not about the origin of organelles. This is Margulis and Williamson at their most loony. We're talking insect larvae from Onychophora genomes loony.

      Mutationism: how is this different from the standard view of evolutionary constraint and canalization?

      Delete
    2. Re: Symbiogenesis (endosymbiotic ‘theory’)
      I agree with Taylor. Acquiring complexity through symbiosis is a perfectly respectable idea that dates from Schimper (a Darwinian adaptationist) in the 19th century. This is quite different from the equally old yet ‘full-tilt wacko’ proposal of generalized species formation, including hopeful monsters, through hybridization. These are two ideas with two levels of sanity. It is unfortunate that Moran conflates them. Symbiogenesis, a lá Schimper and promoted by Lynn Margulis, certainly deserves a place on evolutionary biology’s center stage; ‘hybridogenesis,’ also promoted by Margulis, is fit only for the trash bin.

      I maintain my vote for symbiogenesis, but in the original Schimperian sense of the term.

      W. Benson

      Delete
  8. Theistic evolution as part of a new synthesis? Seriously? These guys must be absolute ass-holes.

    ReplyDelete
    Replies
    1. Are you referring to Francis Collins and Ken Miller?

      Delete
  9. How is convergent evolution a part of evolutionary theory? It's an observation that goes in, or a prediction that comes out-- it's not a "theory." Sure, you can do some simple calculations via population genetics, but it's the same calculations as for anything else.

    The fact that somebody would list this as even theoretical indicates that they were not thinking.

    ReplyDelete
    Replies
    1. It refers to the ideas of Simon Conway Morris (and others) who argue that there's a direction to evolution and that the constraints on vertebrate evolution will have led inevitably to a conscious god-fearing species like humans.

      The constraints are built into the process and the process was initially created by god for the purpose of evolving us (or something like us).

      Delete
    2. Convergent adaptive evolution is an integral part of the 'old' synthesis. Mimetic convergence was one of R. A. Fisher's big topics in his Genetical Theory of Natural Selection.

      Delete
    3. Morris convieniently neglected a conclusion to his arguement. He just didn't realize that he was forming his own Evo-Devo scenario. We evolve until we believe and then it's down the slippery slope of devolution. Sorta like, "I believe, therefore I ain't."

      Delete
  10. Is anybody else than Shapiro really considering Natural Genetic Engineering?

    ReplyDelete
    Replies
    1. Not so far but there's 29 more days of voting. :-)

      (It needs TWO votes since I'm assuming Shapiro will vote for it.)

      Delete
  11. Hey Larry, you left POOF! off of the list. Shame on you. ;)

    ReplyDelete
  12. Would non-adaptive evolution of complexity mean Michael Lynch's stuff?
    If so, I can understand it as interesting; and it is certainly after 1950, if that's the criterion for Modern Synthesis.
    Phenotypic plasticity can be regarded as totally standard quantitative genetics, and something totally different from West-Eberhard's developmental plasticity. So what is meant?

    ReplyDelete
  13. I'm not sure scientific theories get improved by "adding topics" to them.

    ReplyDelete
    Replies
    1. I though that Darwin's original theory was vastly improved by adding population genetics. Do you agree?

      Delete
    2. I think it was not "Darwin theory plus population genetics", it was population genetics applied to Darwin theory, and Darwin theory being re-shaped and re-formulated by population genetics. Not a sum. The word Synthesis means something different than a mere sum of things or an "extension" of one thing with a bunch of other things.
      Take Epigenetics, for instance. You can *add* a chapter on Epigenetics to an Evolution book but... to the Evolutionary Theory?

      Delete
  14. Are jumping genes, punctuated equilibria and drift missing because you consider them ginven by now - or the contrary?

    The synthesis seems to extend all the time without anybody deciding on it in votes.

    ReplyDelete
  15. I find it strange that these "extended synthesis" discussions always manage to avoid mentioning one of the hugest things that has happened in the last 30 years in evolutionary biology, i.e. phylogenetics and "macroevolution" in the sense of lineage dynamics (the factors that influence rates of lineage splitting and lineage ending, ie extinction). "Species sorting" does that a little bit but its basically a term from the 1980s that no one uses...

    ReplyDelete
  16. Species sorting" does that a little bit but its basically a term from the 1980s that no one uses..

    A quick PubMed search for "species sorting" and "species selection" suggests otherwise. Besides, I seem to remember a little book by Stephen Jay Gould (2002) that may have mentioned the topic. :-)

    ReplyDelete
  17. I humbly submit "Abracadabra."
    If Theistic Evolution makes the cut...

    ReplyDelete
  18. Could we discuss the underlying premise that any of a list of concepts or causes or phenomena may be added to the "Modern Synthesis" (MS)?

    If the MS is a theory, then it has a logical structure, and whether or not a new proposition can be added to the theory depends on the relation of the new proposition to the old structure.

    I hope that there is some useful clarification of the concept of "theory" in a blog that I wrote a few years ago for Sandwalk (http://www.molevol.org/cdblog/theory_vs_theory), in which I argued that scientists constantly conflate "theoryC" (concrete, conjectural) in the sense of a grand conjecture, with "theoryA" (abstract, analytical) in the sense of a body of abstractions. For examples of the confusion, read the wikipedia article on "theory", or NCSE's apologetics.

    The premise of Larry's poll, it seems, is that the MS is NOT a theory, but a school of thought, i.e., MS ::= collective beliefs of the cohesive and mutually self-congratulatory group of people who identify with the MS tradition-- all the folks who look to Mayr, Dobzhansky, Fisher, Darwin etc as their intellectual forebears. A more succinct definition given to me by a famous evolutionist is that neo-Darwinism "means whatever we say it means". A theory has a logical structure, but a school of thought can hold any beliefs, including ones that it rejected previously. For instance, Allen Orr is obviously considered part of this school, yet his publications and his theoretical developments invoke a "lucky mutation" view rejected by Mayr, et al and understood to be anti-Darwinian. Orr and Coyne helped to bring down the "micromutationist" view that previous Darwinians saw as an integral part of Darwin's legacy, but now Coyne is famous as a reactionary defender of Darwinism.

    But I'm not very interested in the queer sociology of "Darwinism" as a school of thought. I think it would be more interesting, and scientifically productive, to (1) assume that the MS has a structure, (2) discern what is that structure from what Mayr, et al say about evolution, and how this differs from what opponents said about evolution, and (3) consider what about "evo-devo" (for instance) might call into question that structure.

    ReplyDelete
  19. The modern synthesis was missing the whole field of symbiology - not just symbiogenesis. There was a big revolution in the 1960s-1980s surrounding its incorporation into evolutionary theory.

    ReplyDelete