Evolution for Everyone

The evolutionary community is as active as an alarmed beehive over the critique of inclusive fitness theory recently published in the journal Nature by Martin Nowak, Corina E. Tarnita, and E.O. Wilson. I do not agree with them in every respect but I’m glad that they have aroused the evolutionary community from its stupor. The general public and majority of evolutionary biologists have a pre-1975 understanding that hasn’t even kept pace with modern inclusive fitness theory, not to speak of the debates that will be taking place among the cognoscenti. This is an opportunity for everyone to take stock of the core issues at stake.

It is important to realize that numerous issues are at stake that must be examined one by one. It doesn’t help that Richard Dawkins continues to issue boneheaded statements about group selection, as I recount in my previous post. Inclusive fitness theorists should be joining me in pointing out the errors of these statements, just as I intend to join them in pointing out some errors in the Nowak et al. critique.

In this post I want to focus on a statement that Nowak et al. make in the caption to figure 3 that “inclusive fitness theory…is an alternative accounting method, but one that works only in a very limited domain.”

What does it mean for a theory to function as an accounting method? Consider the standard definition of genetic evolution, which is a change in the gene frequency of a population for any reason, whether selection, drift, linkage disequilibrium, and so on. It is important for the definition to include any kind of genetic change, just as it is important for a financial accounting method to include all monetary inputs and outputs. It is equally important for the accounting method to provide meaningful categories of change such as selection, drift, and linkage disequilibrium, whose relative importance must be determined on a case-by-case basis. After a lot of hard empirical research, we can say that guppy spots and finch beaks evolve largely by natural selection, that peacock tails evolve largely by sexual selection, that some base pair substitutions are selectively neutral and evolve by drift, that haplotypes reflect linkage disequilibrium, and so on.

It is important for a theoretical framework to function as an accounting method, but we haven’t made much progress merely by pointing out the fact. If I boast to you that my bank account keeps track of all deposits and withdrawals, your appropriate response would be “of course it does–if not you should switch banks”. Similarly, if I boast that my theoretical framework for studying evolution keeps track of everything that evolves, your appropriate response would be “of course it does–if not you should change your theoretical framework.”

Evolutionary theory includes a number of different frameworks such as multilevel selection theory, inclusive fitness theory, and what Dawkins calls gene selection theory, that all claim to function as good accounting methods. This is a bit like different banks that all keep track of deposits and withdrawals but differ in how they are categorized. One might categorize them according to dates, another according to their tax-exempt status, and so on. There might not be a single best accounting method, providing a justification for several to coexist. If so, then it becomes necessary to translate between accounting methods. The statement “this deposit was made on July 16, therefore it is not tax-exempt” is obviously stupid, but equivalent statements are made all the time by evolutionary biologists who don’t know how to translate among their various different accounting methods.

Against this background, I can begin to articulate my agreements and disagreements with Nowak et al. One of their claims is that the accounting method known as inclusive fitness theory has led to no useful insights whatsoever. That claim is too harsh. I’m happy to credit inclusive fitness theory with useful insights.

Nowak et al. also seem to contrast inclusive fitness theory with what they call “standard natural selection theory”, as if the point of inclusive fitness theory is to add some additional factor. This is poor phrasing on their part. What they mean to say, if I understand them correctly, is that inclusive fitness theory attempts to function as an accounting method. To the extent that it succeeds, every statement made within the rubric of inclusive fitness theory can be translated into the rubric of explicit models of natural selection in multi-group populations.

The next question is how well inclusive fitness theory functions as an accounting method. Here, Nowak et al. score some valid points about the simplifying assumptions made by inclusive fitness theory that limits its generality, or “works only in a very limited domain”, as they put it. Simplifying assumptions are a two-edged sword; all theories require them but they can be terribly misleading when a theory is applied to situations where the assumptions don’t hold. Few people who use inclusive fitness theory are aware of the long list of simplifying assumptions that result in Hamilton’s deceptively simple rule. Nowak et al. are performing a service to the evolutionary community by challenging the assumptions and forcing them to be openly discussed.

All this talk about alternative accounting methods ultimately becomes boring, like arguing over whose bank is better. The purpose of all accounting methods is to make sense of the evolutionary process, leading to the evaluation of factual claims such as “genealogical relatedness is required for the evolution of altruism” or “altruism is locally disadvantageous and requires a positive selective differential at a larger scale to evolve in the total population.” It is important to remember that there is such a thing as an empirically validated fact that all accounting methods must agree upon to remain correct. In my next installment, I’ll consider some of the factual claims associated with inclusive fitness theory, some that have survived the test of time and others that have turned out to be just plain wrong.

Comments

  1. #1 Dan Slaby
    September 4, 2010

    The problem with applying accounting methods to biology is that accounting methods have to balance base on credits and debits, whereas biological changes involve natural selection where the the gain does not have to be offset by the loss. We should be careful when we apply money as the measure of all things.

  2. #2 bob koepp
    September 5, 2010

    I think the statement by Nowak et al. was meant to suggest that within the “limited domain” in question, the alternative theories are “notational variants.” But to be persuaded, I’d want to see a demonstration that the relevant terms of theories A and B are intertranslatable.

  3. #3 Mike Keesey
    September 5, 2010

    @Dan Slaby, I think you’re taking the metaphor too far.

  4. #4 Jim Calhoun
    September 5, 2010

    @Dan Slaby: All systems involve profit and loss. Biological systems contain so many factors however that not all of debits and credits will be readily apparent. This is further complicated by the fact that there are always changes from generation to generation even though parent and child seem identical. Every gain is offset by a loss. Example: Our ancestors climbed out of the trees and gained improved vision and a larger brain. We lost upper body strength and body hair.

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  6. #6 Ben Allen
    September 7, 2010

    David,

    You are one of the few thoughtful voices I have seen on this issue. Thank you for taking the time to understand this work.

    To clarify: Nowak et al. indeed argue that inclusive fitness theory is an accounting method, an alternative to standard natural selection (i.e. “direct fitness”).

    Since accounting methods make no predictions of their own, they cannot be empirically tested. They can, however be evaluated on two criteria:

    1. How general is the method? What variety of situations can it handle?

    2. Is the method elegant and/or intuitive? Does it lead to useful insights?

    Nowak et al. argue that inclusive fitness theory falls short on both counts. I’m interested to see where you disagree.

  7. #7 Sam C
    September 9, 2010

    What is this “fitness”, inclusive or otherwise? It’s not a property like electric charge, nose length, etc.

    Fitness is a magical catch-all for boiling down how organisms (or genes) survive and reproduce and how their playmates and relatives do the same. It’s very simplistc. It boils those phenomena dry to a sticky mess.

    Too many of the disputants in this field (DSW included in his invariably patronising articles!) simply do not recognise that they are arguing about something that does not exist. It is their aether.

    This is not mathematical biology or evolutionary biology. This is theological biology. It is valueless. Arguing about the “fitness” of an organism/population/trait/gene is about as useful as arguing about the goodness of its soul or the weight of its spirit.

  8. #8 erpiu
    November 8, 2010

    it looks like many here have missed what the terms of this controversy are. EO Wilson & coterie’s change of mind was forced by 1999 work by James Hunt who studied multiple origins of sociality in a wasp phylogeny in which all the species had about the same “kin selection potential” and yet he found that sociality evolved only when there were very strong “ecological” incentives (Hunt, J. H. 1999. Trait mapping and salience in the evolution of eusocial vespid wasps. Evolution 53: 225-237). But since ~2005 Wilson, Hoelldobler, etc, have hijacked the controversy.

    Some people have indeed started realizing that crucial for the existence/persistence –and thus for the evolution– of animal societies is not (or not so much) “kin selection” but rather the fact that there are very rewarding ecological niches out there in which biomachines that adopt group-approaches to foraging and interference competition are much more effective trophically than are biomachines which adopt “solitary-consumer/fighter/reproducer” strategies.

    This means that the evolutionary-genetical success of the genetic programs encoding such group behaviors is fully subordinate to the existence of such ecological opportunities!

    In other words: people have begun realizing that, e.g., “altruism” is also a wining ecological strategy, rather than just an example of the promotion, or not, of altruism genes and the rejection (or invasion) of cheater genes.

    The social-ant colony, e.g., is an ecological machine that out-competes at the foraging- and interference-competition level most other organisms in almost any terrestrial ecological setting, i.e., a social-ant colony in the field cannot be reduced natural-historically and evolutionary-historically to just an example of an ESS immune to “selfishness” mutations that may undermine the genetic encoding of its sociality.

    EO Wilson indeed has always made a big deal of the fact that ant species monopolize nearly 70% of the insect biomass on earth, but he did not realize the implications of this until the wasp guy rubbed it to him and his coterie while they were still happily repeating the empty syllogisms of kin-selection numerologists [who meanwhile have even almost managed to deny Darwin (sic!) the credit for explaining the existence of sterile ants, etc., when he mentioned in the Origin Species that an individual's sacrifice can benefit the reproduction of relatives, i.e., kin selection].

    This 70% means that evolution by “natural selection of individuals” delivers niche-occupancy strategies that suffice to claim only ~30 of the trophic energy monopolized by the insect Bauplan (assuming termites and other social insects are insignificant biomass-wise).

    The situation among many mammals is the same. Wild-dog packs and hyenas, e.g., beat the hell out of tigers and lions, and biomass wise they dominate.

    It is time for gratuitous faux-a-prioristic misused-math arguments to be confronted with ultimate natural-historical facts.

    And it is also time that the too-many cheapo-applied-math peddlers posturing as evolutionary biologists learn that “natural selection” is not the same as “evolution by natural selection”, that differential fitness is always caused by differential ecological performance (and never by “genes”), and that evolution by natural selection is just something that “may” happen to genes when there is differential ecological performance at some level of biological organization, which however does not “prove” that the differential ecological performance is at the level of molecular interactions of genes (or of proteins; genes may suffice but are not necessary for differential ecological performance, but additive genetic variation in ecological performance suffices for evolution driven by differential ecological performance).

    In other words, Sober’s 1984 [1984 sic!] book “The Nature of Selection” should be required reading for every evolutionary biologist. Sober showed first that the “kin selection” oxymoron is a muddled verbal construct to refer to that special case of group-level differential ecological performance in which “selected” groups happen to also be kin groups (most of the time but not always… see mutualism, e.g.).

    PS. I found this very recent paper below that studied this ecological group-performance vs. “kin-selection” issue within a clade of sponge-living shrimp.

    ===================

    Kin structure, ecology and the evolution of social organization in shrimp: a comparative analysis

    Author(s): Duffy JE (Duffy, J. Emmett)1, Macdonald KS (Macdonald, Kenneth S.)2

    Source: PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Volume: 277 Issue: 1681 Pages: 575-584 Published: FEB 22 2010

    Times Cited: 2 References: 62 Citation MapCitation Map

    Abstract: Eusocial societies present a Darwinian paradox, yet they have evolved independently in insects, mole-rats, and symbiotic shrimp. Historically, eusociality has been thought to arise as a response to ecological challenges, mediated by kin selection, but the role of kin selection has recently been questioned. Here we use phylogenetically independent contrasts to test the association of eusociality with ecological performance and genetic structure (via life history) among 20 species of sponge-dwelling shrimp (Synalpheus) in Belize. Consistent with hypotheses that cooperative groups enjoy an advantage in challenging habitats, we show that eusocial species are more abundant, occupy more sponges, and have broader host ranges than non-social sister species; and that these patterns are robust to correction for the generally smaller body sizes of eusocial species. In contrast, body size explains less or no variation after accounting for sociality. Despite strong ecological pressures on most sponge-dwellers, however, eusociality arose only in species with non-dispersing larvae, which form family groups subject to kin selection. Thus, superior ability to hold valuable resources may favour eusociality in shrimp but close genetic relatedness is nevertheless key to its origin, as in other eusocial animals.

  9. #9 John A. Davison
    December 22, 2010

    The real issue is the eternal battle between theism and atheism. Darwinism is basically an atheist proposal and it is there that it displays its greatest weakness.

    I just addressed this matter at Jason Rosenhouse’s
    blog -

    http://scienceblogs.com/evolutionblog/2010/12/evolution_and_original_sin.php#comments

    I would be interested in any response it might evoke here.

    jadavison.wordpress.com

  10. #10 John A.Davison
    December 23, 2010

    Natural selection is very real but its role has been entirely anti-evolutioary, serving to prevent rather than promote evolutionary change. Leo Berg recognized this in 1922 as did Reginald C. Punnett and William Bateson before him.

    “The struggle for existence and natural selection are not progressive agencies, but being, on the contrary, conservative, preserve the standard.”
    Nomogenesis, page 406

    The primmary role for natural selection has always been the same. It is to preserve the species for as long as possible, a process which, with very few exceptions, has resulted in extinction. That is all that we see in the contemporary biota, extinction without replacement. I agree with Pierre Grasse that creative evolution is a phenomenon of the distant past -

    “Aren’t our plants, our animals lacking some mechanisms which were present in the early flora and fauna?
    Pierre Grasse, Evolution of Living Organisms, page 71

    (note the contradiction between his statement and the title of his book.)

    “A past evolution is undeniable, a present evolution undemonstrable.”
    John A. Davison

    jadavison.wordpress.com

  11. #11 John A. Davison
    December 25, 2010

    Since my comments are being ignored, below is my parting message for this weblog. From my weblog and the page concerning my book “Unpublished Evolution Papers of John A. Davison.” -

    John A. Davison – December 25, 2010 [Edit]
    The most revealing feature of my book is the absence of any subsequent reviews of its contents, especially since it received 5 stars from Terry Trainor and Dublin Evans, neither of whom had even read it. However, they each were very familiar with my science and I am pleased with their confidence. I am especially grateful to Terry Trainor who can endorse views some with which he probably does not agree. That is a rare and admirable characteristic these days marked by armed camps and rampant intolerance of dissenting opinions.

    Incidentally, Terry Trainor long ago offered his explanation for the absence of reviews by members of the atheist Darwinian establishment.

    “Davison is the Darwinian’s worst nightmare.”

    Surely there must be those who find our thesis an unacceptable interpretation of the living world. Are they unable to counter the alternatives I have presented? Such will remain my conviction until negative reviews appear. I welcome them. Favorably or unfavorably received, we have challenged the whole atheist agenda which the neo-Darwinian paradigm represents. Silence is no longer an option, no longer an acceptable response from the proponents of the most persistent hoax in the history of science. Let us use this opportunity finally to present the issue squarely before the intellectual community, a goal which has never yet been realized.

    “A doctrine which is unable to maintain itself in clear light, but only in the dark, will of necessity lose its effect on mankind with uncalculable harm to human progress.”
    Albert Einstein

    With those words Einstein correctly characterized Darwinism as a doctrine, a mindset, an ideology. Such words apply only to the political realm which is exacty what Darwinism has always been, nothing more than a political party, just as intolerant as the National Socialist party of Nazi Germany or the Communist party of Castro’s Cuba and present day China.

    Merry Christmas

    jadavison.wordpress.com

  12. #12 John A. Davison
    December 26, 2010

    From my webpage -

    456. John A. Davison – December 25, 2010 [Edit]
    http://scienceblogs.com/evolution/2010/09/what_does_it_mean_for_a_theory.php

    I just left three very challenging and unanswered messages at the above blog. I expect others, friend or foe, to respond. I am tired, as were every one of my distinguished sources, of being ignored. That tactic won’t wash any more, at least not with this investigator. There is nothing more cowardly than refusing to respond to those who do not share your convictions. Yet that is exactly what has always been the posture of the “Darwinista,” a century and a half of continuous denial that Darwin’s flight of fancy could possibly be wrong.

    jadavison.wordpress.com

  13. #13 Burch19Angie
    April 19, 2012

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  14. #14 Rachel Scott
    May 1, 2012

    Well i know that nothing was possible without accounting so here i highlight the importance of accounting, this theory also belongs to Function as an Accounting Method.
    http://accountingdegreetalk.org/