Evolution for Everyone

Consider some standard examples of design in nature: the aerodynamic wing of the bird, the concealing coloration of the moth, the dense fur of the polar bear. Darwin’s insight was to explain these adaptations as products of natural selection: individuals vary, some survive and reproduce better than others, and their properties are inherited by their offspring.

All of these adaptations are locally advantageous. Individuals possessing them survive and reproduce better than their immediate neighbors. Now consider some standard examples of social adaptations: the good Samaritan, the soldier who heroically dies in battle, the honest person who cannot tell a lie. We admire these virtues and call them social adaptations because they are good for others and for society as a whole–but they are not locally advantageous. Charitable, heroic, and honest individuals do not necessarily survive and reproduce better than their immediate neighbors who are stingy, cowardly, and deceptive.

How important is this problem? For Darwin, who was formulating the entire theory of evolution, it was one important problem among many. If we restrict our attention to the study of social behavior, however–what E.O. Wilson would later call Sociobiology–it is paramount. Most behaviors that we call prosocial require time, energy, and risk on the part of the prosocial individual. Most behaviors that we call antisocial deliver an immediate benefit to the antisocial individual. If most antisocial behaviors are locally advantageous and most prosocial behaviors are locally disadvantageous, then we have an enormous problem explaining the nature of prosociality, including the nature of human morality, from an evolutionary perspective.

Darwin was aware of this problem and proposed two types of solution. First, he observed that farmers routinely sacrifice some individuals for eating and select their traits by breeding their relatives. Individuals who altruistically sacrifice themselves for their relatives, such as the suicidal sting of the honeybee, might therefore evolve by natural selection. This idea anticipated what later would be called kin selection.

Second, Darwin observed that groups of prosocial individuals will survive and reproduce better than groups of antisocial individuals, even if antisocial individuals have the advantage over prosocial individuals within groups. Here is one of his canonical statements, using human moral virtues as an example (from Chapter 4 of Descent of Man).

It must not be forgotten that although a high standard of morality gives but a slight or no advantage to each individual man and his children over other men of the same tribe, yet that an increase in the number of well-endowed men and advancement in the standard of morality will certainly give an immense advantage to one tribe over another. There can be no doubt that a tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection. At all times throughout the world tribes have supplanted other tribes; and as morality is one important element in their success, the standard of morality and the number of well-endowed men will thus everywhere tend to rise and increase.

In this passage, Darwin clearly demonstrates his awareness that a) moral behaviors are locally disadvantageous or at best deliver no advantage, compared to less moral individuals within the same group, and b) moral behaviors expressed within groups can be decisively advantageous in between-group competition. He didn’t comment on the irony that within-group morality might well lead to immoral conduct among groups.

I will return to this issue later, but for the moment let’s consolidate our gains. The original problem associated with group selection is foundational for the study of social behavior from an evolutionary perspective. Unlike individual-level adaptations such as the polar bear’s thick fur, prosocial behaviors are locally disadvantageous. Fortunately, they are advantageous at the larger scale of whole groups. Prosocial behaviors can evolve by a process of between-group selection, as long as this process is stronger than the opposing process of within-group selection.

Is anyone confused yet? I suspect not. You don’t need to be an Einstein to get the basics of group selection. All of us can appreciate that doing the right thing makes us vulnerable to exploitation. We can equally appreciate that united we stand, divided we fall. Why should such simple ideas become the basis of endless controversy?

Yet, as we proceed, I guarantee that you will become confused. One reason that a truth and reconciliation process is needed for group selection is to return to the simplicity of the original problem and Darwin’s solution. As Ed Wilson and I put it in our recent review article titled “Rethinking the Theoretical Foundation of Sociobiology“: Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.

To be continued.

Comments

  1. #1 David Sloan Wilson
    October 24, 2009

    Now that I have introduced the original problem, I can address the example of the brain worm raised by InfuriatedSciTeacher in comment #6 on T&R I. The brain worm is a trematode parasite that is first ingested by snails, where it reproduces asexually and exits in the form of capsules that are ingested by ants. Within the ant, one individual parasite burrows into the subesophageal ganglion (the ‘brain’) and changes the ant’s behavior, causing it to cling to the tops of grass blades rather than going about its normal duties. This facilitates being eaten by sheep, the next stage of the parasite’s life cycle. This is one of many fascinating examples of parasites that influence the behavior of their hosts, but this one is especially interesting because the individual that burrows into the brain dies in the process. It has sacrificed its life so that the other parasites in the same ant can reproduce.

    To create a mathematical model of this example, imagine two strains of the parasite (A and S). The A strain is altruistically ready to become a brain worm and the S strain selfishly isn’t. Imagine a single ant infected with both types. Let’s say that the ant has 5 individuals of the A strain and 5 individuals of the S strain. One individual of the A strain becomes the brain worm, leaving 4 survivors. The 5 S individuals get the same benefit without any sacrifice. It is clear that S has the advantage within the group, just as Darwin conjectured for human moral traits. To frame the same example in human terms, imagine a group of soldiers in a desperate situation who agree to draw straws for one to go on a suicidal mission to save the others. Some members of the group opt out of the lottery but get the same benefits. Would they be selfish compared to the altruists who entered the lottery? You bet!

    The same advantage of S over A will exist within each and every ant containing both types, which is why I called attention to the brain worm as an elegant example of the original problem in a 1977 paper. How about the solution? There are many ants infected by brain worms, so the total parasite population consists of multiple groups. All ants with at least one member of the A strain will have the same elevated chance of being eaten by a sheep, but ants consisting entirely of the S strain will have a smaller chance. Thus, the differential contribution of groups to the total gene pool will favor the A strain, even though it is selectively disadvantageous within each and every group.

    What is the final outcome, considering both within- and between-group selection? That depends upon how the two strains are distributed within and among groups, which in turn depends upon details of the biology (how many strains enter a single snail, how many capsules are ingested by a single ant, etc). Regardless of the details, however, we can see the brain worm as an elegant example of the original problem that Darwin identified, and between-group selection as a solution.

    One reason that this was not apparent from InfuriatedSciTeacher’s description is because of the frame of comparison. InfuriatedSciTeacher was noting that some individuals in the same ant are genetically identical by virtue of the asexual reproduction that took place in the snails. True, but this does nothing to prevent A from being locally disadvantageous within groups. Different frames of comparison plague the group selection controversy, as we will see. In order to think in terms of within- and between-group selection, it is necessary to compare relative fitnesses within and among groups.

  2. #2 Bob O'H
    October 24, 2009

    Prosocial behaviors can evolve by a process of between-group selection, as long as this process is stronger than the opposing process of within-group selection.

    Is this how Wynne-Edwards explained group selection? I haven’t seriously delved that far back into the history of the debates to see.

  3. #3 piker
    October 24, 2009

    As long as you persist with your belief that your mathematical models are sufficiently accurate to decide upon what works for you in your philosophy, you will also persist in making the same mistakes as to the degrees of any accuracy involved.
    Cases in point: Hundreds Of Natural-selection Studies Could Be Wrong, Study Demonstrates
    http://www.sciencedaily.com/releases/2009/03/090330200821.htm

  4. #4 Ann Klein
    October 24, 2009

    What constitutes moral behavior is determined by one’s tribe. It is disadvantageous to the individual and his or her family to go against the “moral behaviors” dictated by the tribe. Cooperation within the tribe is necessary for the tribe to survive. Moral behavior may mean, don’t kill any member of your tribe, but kill everyone who is not a member. Don’t kidnap another member’s woman, but do kidnap other tribe’s women. It is genetically advantageous for the individual human male to make as many women pregnant as possible; however the tribe may decide that is immoral, or not!

  5. #5 David
    October 24, 2009

    Expanding on Ann Klein’s comment (#4) – our sense of morality seems, in many instances, to be limited to our dealings with those who have some definite relationship to us. Group selection favors development of altruistic behavior but also favors limiting the scope of altruism to those in the same group.

    There are many examples, perhaps none more clear than Leviticus 25:39-44: “‘If one of your countrymen becomes poor among you and sells himself to you, do not make him work as a slave. … slaves are to come from the nations around you; from them you may buy slaves.” The bible itself is seen to be an example of evolution in action !!!

  6. #6 daedalus2u
    October 24, 2009

    I suspect that being able to recognize a member of your near-related group is the reason abilities such as those that cause the uncanny valley evolved.

    http://en.wikipedia.org/wiki/Uncanny_valley

    Triggering xenophobia in non-kin is a good thing.

  7. #7 randyextry
    October 25, 2009

    Why is it assumed that “prosocial behavior” is locally disadvantageous? If cheaters are punished and good samaritans rewarded, prosocial behavior can be locally advantageous. Being selfish runs a risk of being punished (banishment from the group could equal death – strong selection pressure). Individuals who had evolved a conscience could be selected for. The best way to avoid risky, selfish behavior, which could get you banished, would be to have a little voice in your head telling you that such behavior is wrong. I don’t see what is so hard to believe about morality evolving without needing to invoke group selection.

  8. #8 Bob O'H
    October 25, 2009

    What constitutes moral behavior is determined by one’s tribe. It is disadvantageous to the individual and his or her family to go against the “moral behaviors” dictated by the tribe.

    True. But how did these morals come about? why are they don’t groups with them die out?

    Why is it assumed that “prosocial behavior” is locally disadvantageous? If cheaters are punished and good samaritans rewarded, prosocial behavior can be locally advantageous. Being selfish runs a risk of being punished (banishment from the group could equal death – strong selection pressure). Individuals who had evolved a conscience could be selected for. The best way to avoid risky, selfish behavior, which could get you banished, would be to have a little voice in your head telling you that such behavior is wrong. I don’t see what is so hard to believe about morality evolving without needing to invoke group selection.

    Fine, but why should anyone waste their time punishing people for antisocial behaviour? You need punishment to evolve first, before morality, otherwise there is nothing to get morality started.

  9. #9 David Sloan Wilson
    October 25, 2009

    As I prepare to post T&R III, let me summarize and briefly reply to the comments on T&R II, referring to them by number. In answer to (2), Wynne-Edwards is about to make his appearance. With respect to (3), it seems that I can’t win! Part of the received wisdom is that group selection is theoretically implausible, but (3) seems to criticize reliance on theoretical models. Actually, I agree with (3) that excessive reliance on theoretical models can be a problem, because the results of such models are often an artifact of simplifying assumptions. Examples will be provided in future installments. The solution to this problem is not to ignore models but to build up a family of models that systematically relax the simplifying assumptions.

    Comments 4-8 raise issues about social control, which can make prosociality advantageous and selfishness disadvantageous within groups. True, but we still must explain how the elements of the social control system evolved, as (8) notes. If I punish you for harming the group or reward you for benefiting the group, then I have indirectly benefitted the group at my own private expense, qualifying me as an altruist compared to someone who obeys the rules but doesn’t punish. Economists call this the second-order public goods problem; causing others to provide a public good is itself a public good. In the recent evolutionary literature, it is called altruistic punishment and is a hot topic. Most people who study altruistic punishment, such as Herbert Gintis and Samuel Bowles, write about it clearly from a multilevel perspective.

    When social interactions become sufficiently complex, they can result in multiple local equilibria rather than a single outcome. A local equilibrium is internally stable by definition but different equilibria can differ greatly in their group-level properties. A local equilibrium can be highly stable but also highly dysfunctional at the group level, for example. In this case, group selection is required to select among local equilibria rather than continuously working against selfishness. Robert Boyd and Peter Richerson (among others) have developed the important concept of equilibrium selection, again from an explicitly multilevel perspective.

    My own recently minted PhD student, Omar Eldakar, has developed a concept of selfish punishment that goes like this: Selfish individuals have an interest in getting rid of other selfish individuals and being the only ones to exploit the altruists in a group. In this fashion, selfishness becomes a self-limiting strategy. Within-group selection results in a mix of altruists and selfish individuals, rather than just selfishness. Still, this mix is not optimal for the group, so group selection is required to make it more so.

    All of these factors are important but they need to be studied from a multilevel perspective, rather than eliminating the need to invoke group selection. Furthermore, group selection can be highly efficacious without social control, as we will see in future installments. Even when selfishness is in the process of winning within groups, group-level selection can be even stronger and the net effect is for altruism to evolve.

  10. #10 Sam c
    October 25, 2009

    The tyranny of a label: the concept of “fitness” seems to dominate everything. But it’s discussed as though fitness is a measurable quantity like redness, weight, pH or longevity. Fitness is fundamentally different: it’s an abstract and theoretical concoction, an attempt to partition the reproductive effect or potential of individuals among groups, traits, genes, etc.

    In short (as we’re into pithy summaries!): fitness does not exist.

    Your paper is interesting, and thank you for writing it, but it seems to me that it demonstrates that there has been few significant advances in the field in the last 30 years. These arguments sound just like what I was hearing in the late 1970s, and I think it’s a bad sign that this disagreement has not been settled yet. Although clearly that’s not a scientific criterion, applying a bit of Bayesian logic, it suggests that you’re on shakey ground – isn’t 30 years long enough to prove a point?

    I understand the attraction of theoretical models, but that’s not how scientific arguments are won. With biology, it’s got to be in the field.

  11. #11 Oran Kelley
    October 25, 2009

    Just giving some though to what you wrote about Eldakar’s thesis.

    Say we are largely an altruistic flock with some selfish folk mixed in. BUT our ability to distinguish one from the other is pretty faulty–complex social situations make seemingly selfish decisions actually altruistic; or altruistic motives resulting in what seem to be selfish results; or selfish deeds being effectively concealed by altruistic trappings, etc.

    This might easily turn into a situation where you have a class of selfish successfully pursue selfish ends clandestinely and even see to the long-term maintenance of the herd(shepherds), while severely punishing those who pursue selfishness too obviously or destructively (wolves). But from the perspective of the sheep, in the long run they end up as dinner either way.

  12. #12 daedalus2u
    October 25, 2009

    Oran #11, the problem is that you don’t end up with a population of sheep and shepherds, you end up with a population of only shepherds. To the extent that shepherds compete better within the group, they eventually dominate the group. Unless shepherds end up competing so viciously between themselves that sheep are allowed to persist, the sheep don’t persist and shepherds dominate. If a group dominated by shepherds can’t survive (because shepherds can’t digest grass), then groups with shepherds can’t dominate.

  13. #13 Oran Kelley
    October 25, 2009

    Unless shepherds end up competing so viciously between themselves that sheep are allowed to persist, the sheep don’t persist and shepherds dominate. If a group dominated by shepherds can’t survive (because shepherds can’t digest grass), then groups with shepherds can’t dominate.

    Yes, I think that would have to be the case, that shepherds would compete viciously among themselves, as they did in Western society until recently . . . and after that the size of the flock overall began to increase significantly.

    The group, obviously, can’t be dominated in the demographic sense by shepherds in my scheme because it depends on exploitation going on sub rosa. . .

    Another factor that might play a role is the discrimanace of altruism . . . suppose altruism has a tendency to be extended outside the group, shepherds would have a significan selfish interest in playing up the group distinction and limiting altruism to withing the group they dominate.

  14. #14 InfuriatedSciTeacher
    October 25, 2009

    David,
    Thank you for addressing my question at all, much less in such detail. The problem is indeed one of the framework used to analyse the chosen example. I was examining the problem from the level of the allele that favours the predisposition for one larva to become the “brain worm”, which favours itself if many of the larvae in the ant share that gene through asexual or sexual kinship. The benefit appears to be to the group, but is clearly also in action for the allele itself, which is also the replicator that faces selection pressure.
    If both hypotheses actually fit the data equally well, are we not advised to choose the simpler of the two? While I’m asking such questions, what are the relative allelic frequencies of your hypothetical A and S variants within the trematodes themselves? Is it reasonable to suppose that the S variant exists at all, or that it ever existed, without corroboration?

  15. #15 Mike
    October 25, 2009

    @InfuriatedSciTeacher

    […]clearly also in action for the allele itself, which is also the replicator that faces selection pressure.

    Here’s where I think Dawkins’s terminology fatally obscures the facts: genes or alleles are not replicators. They depend crucially on intracellular mechanisms and an appropriate intra-organismic environment for being replicated. So at best they’re “replicatees” 🙂

    But even their central role as objects of replication isn’t really unique. One can make a good case that it’s actually the whole life-cylce which is being replicated generation after generation. This is the idea of the so-called “Developmental Systems Theory”. The works in the field are highly fascinating reads – and the central papers are collect in the book “Cycles of Contingency – Developmental Systems and Evolution” by Susan Oyama, Paul E. Griffiths and Russel D. Gray.

    Of course it is argued that the genome is the bottleneck through which the entire information necessary for replicating the life-cycle (or organism) passes. But even that is IMO a simplification. The information in the cellular systems and organisms in which the genome resides are absolutely crucial. Without the information inherent in the replication systems, the genome is quite meaningless. Furthermore, a lot of the information necessary to replicate the life-cycle is not encoded in the genome itself. There’s the epigenetic information present as self-sustaining loops of gene-activity (where active genes produce proteins that regulate the activity of the gene), there’s the template-copying of cell-structures, there are chromatine markings (DNA-methylation) and there’s RNAi…

    Additionally, the offspring inherits information from the former generation through the parents behavior in rearing the offspring, through their modification of the environment within which the offspring develops (niche-construction) etc.

    There’s a lot of work being done in those fields, and I can strongly recommend the following works:

    “Cycles of Contingency” – Oyama, Griffiths, Gray
    “Evolution in Four Dimension” – Jablonka, Lamb
    “The Origin and Evolution of Cultures” – Boyd, Richerson
    “Culture and the Evolutionary Process” – Boyd, Richerson
    “Niche-Construction” – Laland, Odling-Smee, Feldman

    (You can find copies of at least the first three on the internet – just google for the title in quotes and the term ‘download’)

    In light of the above (but also independently), I don’t think we can speak of the allele or the gene as that which faces selection pressure. The challenges of the environment are faced by the individual and the group (since there are emergent group-level phenomena that benefit its members which depend not on the behavior of each individual for itself, but on the interrelated behavior of the individuals as members of the group).

    If you’re interested, you can also contact me for reading material under mbauer.mphil@googlemail.com

  16. #16 daedalus2u
    October 25, 2009

    Oran, to the extent that shepherdsA are protecting sheep from shepherdsS, shepherdsA are acting altruistically and against their own short term self-interest of exploiting those sheep themselves.

    IST, the behavior of migrating to a certain brain site and modifying it so as to induce a certain behavior is a very complex behavior which (I am virtually certain) requires multiple genes and complex non-gene coding sequences. The default behavior of not migrating to a certain brain site is much simpler and is what would happen were there any disruption to the complex pathway mediating the brain migration behavior. Not all worms so migrate, so there is some regulation of the behavior. Since not all worms end up in the brain, some exhibit the trait of not migrating. Even if the reason some worms don’t make it to the brain is because they are slower, to the extent that the slow migrating trait is heritable it would eventually dominate if there were no group selection.

    I presume sequencing would show this. I think it is unrealistic to assume the S allele does not or never did exist. The ancestral species that first parasitized ants (in all likelihood) could not have exhibited the complex altruistic behavior of manipulating the behavior of the parasitized ant (absent something like Intelligent Design).

  17. #17 Oran Kelley
    October 25, 2009

    deadalus:

    I begin to think that the categories of selfish and altruistic may be a bit too narrowly defined considering the complexities of these sorts of behavior in developed cultures where every behavior has not only an immediate consequence but also down-the-line consequences which the actors may be capable of anticipating. I mean, this long-term selfishness is not long-term as in intergenerational, it is long-term as in next week or next month. It doesn’t seem to me that the categories are sufficiently flexible to accommodate the real situation.

  18. #18 InfuriatedSciTeacher
    October 25, 2009

    Daedalus>

    I presume sequencing would show this. I think it is unrealistic to assume the S allele does not or never did exist. The ancestral species that first parasitized ants (in all likelihood) could not have exhibited the complex altruistic behavior of manipulating the behavior of the parasitized ant (absent something like Intelligent Design).

    The interaction of the worm and the “brain” of the ant would be determinate in just how complex the altruistic behaviour of the migrating worm is or isn’t. We aren’t talking vertebrate brains here, the portion of the ant under influence is a ganglion of far less complexity.
    You find it unrealistic to presume that the S allele does not exist, and I find it equally so to presume that it necessarily does, given that the A allele could also be an exaptation of some other migratory behaviour (benthic infauna, worms included, display diurnal and ontogenetic migratory patterns.) That would of course, also have to be documented or it’s just another “just-so-story”. My point was that the assumption does not make it necessarily so without evidence, in either case.

    Mike> Thanks for the reading suggestions, again.

    There’s the epigenetic information present as self-sustaining loops of gene-activity (where active genes produce proteins that regulate the activity of the gene)

    I find any description of epigenetics that discounts that fact that it is in fact an interaction between genes (and genes and their environment), and therefore something that has to be coded to take place, to be a dodge of genetic reductionism. I fully agree that without the system present to actually replicate the genome (or RNA, take your pick), all we have is a inordinately long polymer that serves no purpose. Are you then proposing that the replication and transcription processes are separately influenced, selected, and inherited? Perhaps I’m taking this for granted, but that process is reasonably constant between organisms of all types, accounting for the interactions of genes present in that organism.
    In reading the provided sources, it occurs to me that my chosen phrasing indicates a bias that I don’t happen to hold. I am quite aware that the phenotypic expression is that which has to interact with the environmental pressures that we term selection. Nonetheless, barring culturally inherited behaviours, it is the genes themselves that are inherited. Basically, I’m not discounting systems biology or stating that we can’t study the properties of emergent systems, but I am stating that in the particular case illustrated there are more parsimonious explanations that fit the observed data equally well. You might also reference my post in TRIII, as I freely admit I had a archaic or misrepresented view of what group selection theory purports to explain in its current inception. One might think you wouldn’t make it through a two degrees in biology (well, one half in bio) without having that presented in a reasonable light as opposed to the predominant view that group selection theory is useless, but obviously that isn’t true.

  19. #19 daedalus2u
    October 25, 2009

    Oran, yes not just in developed cultures (a term I don’t like), but in undeveloped cultures, and even in non-cultures and actually in every circumstance other than a cartoonishly simplistic mathematical model. Mostly we don’t know what the actors may or may not be anticipating or how their physiology has primed them to behave with or without conscious (or even unconscious) intervention.

    The categories of selfish and altruistic behaviors are human anthropomorphic projections of human values onto non-human actors. Such projections are problematic because the definition of the behavior itself imputes a conscious motivation to it; a motivation that we know is not there. The worm that immolates itself and causes an ant to climb a blade of grass does not have the cognitive capacity to have either “selfish” or “altruistic” behaviors (as humans understand the terms).

    I think the tendency of many humans to only see things in anthropomorphic terms is quite problematic in trying to understand reality. I think this is a major problem in science and in other fields. I think this is extremely difficult for most people to appreciate because they are forced to think with the cognitive structures that they have, and those cognitive structures evolved more for understanding the behaviors of other humans, rather than to understand the physical world.

    I try to explain this concept in my post on my hypothesis behind how I think autism spectrum disorders evolved, as a “feature” to optimize brain function in response to the limited size of the maternal pelvis. The best time for optimizing brain functions is during the first trimester when the anatomy of the brain is being generated. The maternal pelvis limits the size of the brain at birth.

    http://daedalus2u.blogspot.com/2008/10/theory-of-mind-vs-theory-of-reality.html

  20. #20 Mike
    October 25, 2009

    @InfuriatedSciTeacher

    Mike> Thanks for the reading suggestions, again.

    …glad you found them interesting.

    I find any description of epigenetics that discounts that fact that it is in fact an interaction between genes (and genes and their environment), and therefore something that has to be coded to take place, to be a dodge of genetic reductionism.

    As far as the example you quoted goes, I can see your point. I don’t think it’s a dodge though, as the state of activity isn’t itself encoded, but rather a product of the expression – but yes, it’s an interaction of the gene with itself mediated by the transcription mechanisms.

    But there’s still DNA-methylation, where the crucial information is not coded in the genome itself, as well as RNAi, where the central role is played by the interfering rna itself, not by the genetic code the methylation and transcription of which it controls. And as for the template-copying inheritance of cell-structures, that takes place basically without the genome contributing anything of interest.

    Are you then proposing that the replication and transcription processes are separately influenced, selected, and inherited?

    At least I didn’t mean to propose all of that 🙂
    But seeing as certain cell-structures necessary for the reduplication and transcription mechanisms to work are inherited from cell-generation to cell-generation via template copying rather than encoded in the genome, I’d say that at least that part is separately influenced, selected and inherited. Though I don’t think there’s much room for variation in template-copied structures. When it comes to DNA-metyhlation, though, there’s a lot of room for variation and selection, and at least partly the chromatine markings are inherited even in sexual reproduction without being encoded in the genome.

    In light of that, I would say that even barring behaviorally and culturally inherited information, it’s not exclusively the genes that get inherited. Furthermore, I rather like the perspective that takes the life-cycle as that which is replicated.

    […] I am stating that in the particular case illustrated there are more parsimonious explanations that fit the observed data equally well.

    Concerning the trematode parasite, that might be the case, though I’m not sure it fits equally well as a solution to the problem that the A allele is disadvantageous. But I’m certainly open to the possibility that group selection is superfluous here.

    One might think you wouldn’t make it through a two degrees in biology (well, one half in bio) without having that presented in a reasonable light as opposed to the predominant view that group selection theory is useless, but obviously that isn’t true.

    My girlfriend is currently writing her bachelor’s thesis in biology – and having witnessed the amount of material she had to study, there was barely any time to discuss group selection, or the more philosophical aspects of evolutionary biology in general. To be honest, I don’t see how that should have fit in there, as about 95% of what she had to learn was more basic and (it can be argued) more necessary for becoming a qualified biologist in the first place. That’s why I try to encourage biology students (and those interested in evolution) to read a few of the interesting more theoretical theories and discussions in their spare time, as I think they are absolutely fascinating (more fascinating IMO as stuff like ‘systematics of plant classification’ or 90% of what you learn in mycology etc).

    But one would hope that institutions would make a seminar in philosophy of biology mandatory for grad students at least(taking on topics like reductionism, group selection, ‘units and levels of selection’, ‘multiple inheritance systems’ and ‘definitions of fitness’).

    On a side note, I take it that that’s your blog on blogspot? If so, I hope you don’t mind that I sent you a mail concerning the relevant literature. Because I don’t think I can make as good a case for Developmental Systems theory or Multiple Inheritance Systems as the original authors can themselves. But if you do mind – just ignore or delete it.

    Best wishes,
    -Mike

  21. #21 Oran Kelley
    October 26, 2009

    Curious why the objection to the word “developed.” Surely the complexities of social and cultural interaction “developed” over evolutionary time, no? As the brain developed, as the capacity of actors to anticipate and modify behavior developed (not much seen in ants, say), and as the ability of cultures to preserve the benefits of past experience developed, imperfectly, in oral and written traditions and more recently, in science.

    It would seem clear to me that the complexity and layeredness of these situations is developing even now in human societies.

  22. #22 InfuriatedSciTeacher
    October 26, 2009

    Mike>
    Yes, that’s my blog on blogspot… as I’m presently a public HS teacher in the Bible belt, I thought posting my name next to the big scarlet A, and some of the things I write, might be frowned upon. Emails are welcome, yours more than the generic “you’re an idjit and goin’ to burn in hell because you don’t believe in my god” type I sometimes receive.

    At least I didn’t mean to propose all of that 🙂
    But seeing as certain cell-structures necessary for the reduplication and transcription mechanisms to work are inherited from cell-generation to cell-generation via template copying rather than encoded in the genome, I’d say that at least that part is separately influenced, selected and inherited. Though I don’t think there’s much room for variation in template-copied structures. When it comes to DNA-metyhlation, though, there’s a lot of room for variation and selection, and at least partly the chromatine markings are inherited even in sexual reproduction without being encoded in the genome.

    I didn’t think you did, thus the question instead of a direct retort. I don’t see enough variation in duplication and transcription mechanisms to claim that they’re currently selected for or against. Particularly because it’s not as if ours are any different from any other eucaryote. If you wanted to argue that the processes had to be fixed by a form of selection at some point in the history of life, I wouldn’t disagree with that. It’s also entirely possible that the chemical structures and reactions that preclude the process don’t work in any other manner (biochem was over 10 years ago, and at 8am). I’ll check out the sources on the other aspects… Most of my study has dealt with ecological systems, life histories of certain phyla, and evolutionary reasons behind those, so micro and molecular, while not lost on me, aren’t my strong suit either.
    As for the trematode parasite conversation, the A allele is disadvantageous to the particular worm that becomes the “brain worm”. If we were talking of a genetically diverse population, invoking group selection would seem apt. If, as I have pointed out, the ant ingests a number of identical twins/clones, group selection isn’t necessary bnecause the allele (or combination thereof, I don’t know the exact correlation) is benefitting itself, whereas the S allele gains no such benefit if not randomly in the same host as an A allele. This alone is enough to change allelic frequencies in the population.
    Those studenty things of mine are finishing their midterm and a bit restless, I’ll respond more later.

  23. #23 abb3w
    October 26, 2009

    The problem reduces to the Ship of Theseus: what does one mean by “individual” given change as a function of time?

    Ann Klein What constitutes moral behavior is determined by one’s tribe.

    No; moral behavior is strongly influenced by one’s tribe. However, one retains the moral option to choose a different tribe, which on seldom occasions can be advantageous to both the individual and the new tribe. (In the mathematically degenerate case, the “new tribe” may be the individual alone.)

    Ann Klein It is genetically advantageous for the individual human male to make as many women pregnant as possible; however the tribe may decide that is immoral, or not!

    I would distinguish this as “ethical” rather than “moral”. The general question of ordering choices on a good/evil scale is what I mean by “morality”; the particular rules used by individuals (including individual cultures) to compute decisions are “ethics”.

    Bob O’H Fine, but why should anyone waste their time punishing people for antisocial behaviour? Y You need punishment to evolve first, before morality, otherwise there is nothing to get morality started.

    I think a mere short term advantage to providing the punishment is sufficient. EG: forfeiture of the offender’s property to the punishing.

    David Sloan Wilson: Within-group selection results in a mix of altruists and selfish individuals, rather than just selfishness. Still, this mix is not optimal for the group, so group selection is required to make it more so.

    You appear in those statements to implicitly presume the optimal condition exists in reality.

    Also, having a varying degree of probability for altruism/selfishness provides more sophisticated nuance than the simple binary model; in light of which, consider Haidt’s INGROUP as moderator for FAIR and HARM. Competition between groups may evolutionarily select for the more effective nuance (or perhaps, probability distribution over a population for individual probable distribution of altruism-through-selfishness), provided the local cost is low.

  24. #24 Konohana Sakuya Hime
    October 9, 2010

    “Now consider some standard examples of social adaptations: the good Samaritan, the soldier who heroically dies in battle, the honest person who cannot tell a lie. We admire these virtues and call them social adaptations because they are good for others and for society as a whole–but they are not locally advantageous.”

    Well, they may not be locally advantageous in all settings for all individuals, but mightn’t they work to advantage in, for instance, a small society in which most individuals are related to one another – the kind of small societies in which early humans lived? If you are a good Samaritan to your third cousin, or you heroically die in battle for your clan, or you never lie/cheat your neighbors who just happen to be your fifth cousins, well then – don’t your genes benefit all the same?

    I don’t think group selection has to be invoked to explain why such behaviors might arise. (Perhaps you have addressed this in later postings. I’ve only read the first two so far!)