Home » The Design of Life » Human Origins: The Darwinian left discovers “group selection”

Human Origins: The Darwinian left discovers “group selection”

At the Huffington Post, Dan Agin has announced that  Dawkins’s famous selfish gene is laid off. Terminated. Pink slipped. Out of a job:

For nearly half a century, the evolution of human behavior has been presented to the public framed by the ideas of Edward O. Wilson, Richard Dawkins, and a cohort of sociobiologists, evolutionary psychologists, and media gene-mongers. The scientific basis for the frame is the idea that the focus of Darwinian natural selection is the selfish gene, selection always acting within groups and never between groups — individual selection rather than group selection, the unit of selection the gene. From this has followed the selfish-gene evolutionary analysis of various human behaviors, especially the analysis of altruism.

Well, it seems that the father of sociobiology, E.O. Wilson has changed his mind: in the current issue of New Scientist (November 3, 2007), evolutionary biologists David Sloan Wilson and Edward O. Wilson effectively end the hegemony of the selfish gene idea: they review the field and declare in a voice loud and clear that group selection was mistakenly cast aside during previous decades, that the evidence for group selection is too strong to be ignored, and that the current ideas about how evolution works need to be revised.

The scientific revision, well-known to professional biologists, has actually been in the works for more than a decade (see, Wilson, D.S. & Sober, E. (1994). Reintroducing group selection to the human behavioral sciences. Behavioral and Brain Sciences 17(4): 585-654) but with this new article in the popular media the public revision begins.

Groups with more altruists (people who care about you) do better than groups with fewer altruists?

Okay, if that’s a big surprise, we need to change our idea of what constitutes a “big surprise.” But what big revision is now foreseen? Didn’t everyone except the village atheist know this already?

Akin goes on to enthuse,

Humans are pack animals. We live and die in herds. The group provides the individual with the means of physical and psychological survival. We need the group as much as the group needs us. It’s a fair trade that’s been evolving for millions of years.

Herds. Pack animals. Hmmmm … not so good. Not like – for example – the Christian concept of the Body of Christ.  A laggard in the herd is definitely expendable. But even if you are only a toe in the Body of Christ, if you get stomped on  …  

More pressing: Just what rights does this alleged new insight on the part of the wizards of Darwinism give “the group”, one wonders. Especially in view of the fact that

There will be die-hards. There are people who don’t like the idea that society is as important as genes in determining behavior. They don’t like the idea that nature can select societies as well as individuals.

Now, I would like to know how “nature” “selects” “societies.”

If “nature” is Darwin’s natural selection, then the case is clear. Darwin’s natural selection can only select between randomly mutated genes in individuals (natural selection acting on random mutation). That means individuals, not groups.

Dawkins was right about that, even if he was wrong about almost everything else. So how exactly IS society important?

Well, it is, but … mainly by subverting any type of evolution that is driven by some  program other than the human society. Historically, people have worked to subvert nature. We segregate ourselves from nature. Entire industries fret about that fact and market “natural” products.

We also act against nature. Think of all the people who lavish attention on disabled friends and relatives instead of eating them or throwing them off a cliff.

It has been so from the beginning. And it never contributed anything to Darwinian fitness OR group selection. Many groups would be materially better off, no doubt, if they had got rid of their elderly dependents, and yet they did not.

There isn’t really any “group selection”. There are societies that people are willing to belong to and societies that they are not willing to belong to. That has been the story of human history from the beginning. The only selection force is the decisions made by human beings.

But – oops – we are not supposed to believe that, are we? It might imply that there is a  spiritual brain.

I can’t help wondering how much of the “group selection” fad is driven by the recent meltdown of the career of anti-theist James Watson (of double helix fame), for uttering politically incorrect thoughts.

For more on the Darwinian left, go here and here.

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22 Responses to Human Origins: The Darwinian left discovers “group selection”

  1. At some point we have to make a distinction between “refining” the theory of evolution, and admitting that much of the theory is absolute bullshit.

    Seriously, does anyone actually know anything?

  2. The theory of evolution is false. The true of origins is an Intelligent Design/Genetic Entropy .

    The basic rule for the can be stated something like this:

    The ID portion of the holds that a parent species is “designed” with front loaded (CSI) information for all sub-speciation events to occur away from it.

    The Genetic Entropy portion of the holds that:
    All favorable sub-speciation events to different environments will always come at a cost of information from parent species. (i.e. Less genetic diversity of sub-species than for parent species even though sub-species is better adapted for a particular environment)

    The Genetic Entropy portion of the also holds that meaningful information can never increase above the level that was present in the parent species.

    A friend challenged me on the Genetic Entropy portion of the ,for it is scientifically known that (non-living) HIV viruses have verifiably gained a trivial amount of complexity in 10^20 tries of RV/NS.

    Yet the Genetic Entropy portion of the turns out to be robust even to the level of (non-living) viruses because of this fact:

    Is the overall principle of entropy (The Second Law) wrong when rocks pile up at a bottom of a mountain?

    No, of course not, The entropy was payed for by the mountain when rocks disintegrated from the mountain side.

    Thus, in defense of Genetic Entropy, I maintain that the integrated complexity of life, when viewed as a whole symbiotic entity, gives Genetic Entropy its foundational validity.
    Thus I maintain that Genetic Entropy is obeyed for the “trivial” gain in complexity (information) of the “non-living” virus (which infected a living host) will always come at a cost of complexity (information) to the “higher living organism” it has infected”.

    That is to simply say, more complexity will always be lost from a living organism than is ever gained by the non-living virus.

    The is robust and will hold true through rigorous analysis!

  3. Redo:

    The theory of evolution is false. The true mo^del of origins is an Intelligent Design/Genetic Entropy mo^del.

    The basic rule for the mo^del can be stated something like this:

    The ID portion of the mo^del holds that a parent species is “designed” with front loaded (CSI) information for all sub-speciation events to occur away from it.

    The Genetic Entropy portion of the mo^del holds that:
    All favorable sub-speciation events to different environments will always come at a cost of information from parent species. (i.e. Less genetic diversity of sub-species than for parent species even though sub-species is better adapted for a particular environment)

    The Genetic Entropy portion of the mo^del also holds that meaningful information can never increase above the level that was present in the parent species that was designed.

    A friend challenged me on the Genetic Entropy portion of the mo^del ,for it is scientifically known that (non-living) HIV viruses have verifiably gained a trivial amount of complexity in 10^20 tries of RV/NS.

    Yet the Genetic Entropy portion of the turns out to be robust on further analysis, even to the level of (non-living) viruses because of this fact:

    Is the overall principle of entropy (The Second Law) proven wrong when rocks pile up at a bottom of a mountain?

    No, of course not, The entropy was payed for by the mountain when the rocks disintegrated from the mountain side.

    Thus, in defense of Genetic Entropy, I maintain that the integrated complexity of life, when viewed as a whole symbiotic entity, gives Genetic Entropy its foundational validity.
    Thus I maintain that Genetic Entropy is completely obeyed, for the “trivial” gain in complexity (information) of the “non-living” virus (which infected a living host) will always come at a cost of complexity (information) to the “higher living organism” the virus has infected”.

    That is to simply say, more complexity will always be lost from a living organism than is ever gained by the non-living viruses that infect the higher organism.

    The is robust and will hold true through rigorous analysis!

  4. Redo:

    The theory of evolution is false. The true mo^del of origins is an Intelligent Design/Genetic Entropy mo^del.

    The basic rule for the mo^del can be stated something like this:

    The ID portion of the mo^del holds that a parent species is “designed” with front loaded (CSI) information for all sub-speciation events to occur away from it.

    The Genetic Entropy portion of the mo^del holds that:
    All favorable sub-speciation events to different environments will always come at a cost of information from parent species. (i.e. Less genetic diversity of sub-species than for parent species even though sub-species is better adapted for a particular environment)

    The Genetic Entropy portion of the mo^del also holds that meaningful information can never increase above the level that was present in the parent species that was designed.

    A friend challenged me on the Genetic Entropy portion of the mo^del ,for it is scientifically known that (non-living) HIV viruses have verifiably gained a trivial amount of complexity in 10^20 tries of RV/NS.

    Yet the Genetic Entropy portion of the turns out to be robust on further analysis, even to the level of (non-living) viruses because of this fact:

    Is the overall principle of entropy (The Second Law) proven wrong when rocks pile up at a bottom of a mountain?

    No, of course not, The entropy was payed for by the mountain when the rocks disintegrated from the mountain side.

    Thus, in defense of Genetic Entropy, I maintain that the integrated complexity of life, when viewed as a whole symbiotic entity, gives Genetic Entropy its foundational validity.
    Thus I maintain that Genetic Entropy is completely obeyed, for the “trivial” gain in complexity (information) of the “non-living” virus (which infected a living host) will always come at a cost of complexity (information) to the “higher living organism” the virus has infected”.

    That is to simply say, more complexity will always be lost from a living organism than is ever gained by the non-living viruses that infect the higher organism.

    The mo^del is robust and will hold true through rigorous analysis!

  5. 5
    cdesignproponentsists

    I think that unfortunately the Intelligent Design movement has been so caught up with Darwinian evolution that it is forgetting other areas of science (hmph!) and culture that need revolutionizing to bring back purpose and traditional values. Neuroscientists are doing away with the spirit and the soul, claiming that all we are is a biological brain with no REAL intelligence. Anyway, if our brains are just the result of MINDLESS randomness, then how can we trust that what we know is true? (That’s a solid disproof of Darwinism if I ever saw one!) Even cosmologists are slowly beginning to realize that the universe MUST be designed (see the Anthropic principle), but scientific progress is being slowed down in this area by the secularism that pervades the science establishment. Darwinian medicine is ignoring alternative therapies that have been designed very intelligently by our ancestors, e.g. homeopathy, aromatherapy, accupuncture, etc. I think “scientists” at pharmaceutical companies just sit around in labs waiting for a cure for cancer to appear randomly in a test tube because of their Darwinian upbringing. If ID were the dominant paradigm, they would save a lot more money because they would know to use design principles for drug development. Even paranormal sciences need to be reworked. For example, UFO theory believes that there are aliens out there when there is no evidence for it. I don’t believe aliens exist. I think UFOs are angels, and you only have to look at holy scriptures to see evidence of that.

  6. bornagain77:

    The theory you presented suggests a method to prevent HIV from gaining any further complexity. Suppose we collect a tissue sample from every inhabitant of the planet, deep-freeze the samples and store them in a secure location. Assuming the practical difficulties can be overcome, no genetic information possessed by the whole mankind will be lost, not even a trivial amount. Thus HIV cannot gain any new information in the future.

    Is my understanding of Genetic Entropy correct?

  7. …and you only have to look at holy scriptures to see evidence of that.

    …which is a creationist argument, not an ID argument. It may be true, but it’s not ID.

  8. Happy Thanksgiving US residents!

    To the matter at hand: I don’t really get this post. I’m sorry Ms. O’Leary, but this post shows no understanding of the long history of the critique of Wilson’s ideas from the left. Google “Wilson you’re all wet” to see some of the history. There has also been a long history within the scientific literature of such critiques. From that perspective, the idea that Wilson or Dawkins represents “the Darwinian left” is nonsense.

  9. getawitness,

    I think you should make your comment on the Huffington Post and not to Denyse. A left wing blog puts this post up and acts like this is the second coming and it is nonsense. Go there to make your points.

    Group selection is nonsense. All selection is individual. What is missing is that a group is part of the environment that each individual finds himself in and this group environment will affect his differential reproduction as an individual.

    Both Wilson and Dawkins spin sophisticated dribble. Take your pick which one you want to attack. They are all fair game and easy marks. The amazing thing is that these people are taken seriously. It is an indictment of our society as a whole and this is the real worry about where we have come and where we are headed.

  10. Natural selection has long been an ideal vehicle for all kinds of materialistic ideologies, for one very simple reason: it is a tautology.

    In Phillip E. Johnsons’s words, “…the theory predicts that the fittest organisms will produce the most offspring, and … defines the fittest organisms as the ones which produce the most offspring.” (Darwin on Trial, p. 20)

    Wikipedia has a couple of great articles on tautology, one of which states:

    In propositional logic, a tautology … is a propositional formula that is true under any possible valuation (truth assignment) of its propositional variables.

    With natural selection as a given, the only remaining question is: what variables do you care to plug in? Eugenics? Social Darwinism? Communism? A selfish gene? Altruistic group selection? It makes absolutely no difference, because whatever variable you decide to plug in, by definition, has to be true.

  11. Jerry said: “Group selection is nonsense. All selection is individual.”

    True, but a group’s cooperation can lead to a different (positive or negative!) level of reproductive success by a given individual. Thus the individual’s breeding success (or lack thereof) is the result of the group’s selection of which individual’s breeding success is important to the group.

    Obviously, group selection is made up of it members’ (individuals’) collective selection. But “group selection” does exist, and is not nonsense.

  12. Here we go again. Natural selection is not a tautology and Johnson’s comments should be trashed for what they are, nonsense.

    Natural selection is a process that leads to differential increases of some alleles in a population. This happens every day and is not in dispute. If someone wants to describe the members of the population with those alleles as fitter, then fine. But the definition is after the fact and has nothing to do with natural selection or why their percentage increased. Johnson knows this and should be criticized for making the statement. By making the statement it is an indictment of Johnson’s understanding of the process.

    The problem with natural selection is not that this process cannot do something but that the process produces very little of consequence in terms of evolution because of the lack of novel alleles in the populations that favor differential reproduction.

    The problem with neo Darwinism is not natural selection but the appearance of novelty in populations.

  13. Jerry,

    Do you believe Carl Popper also did not understand the theory when he said:
    “Adaptation of fitness is defined by modern evolutionists as survival value and can be measured by actual success in survival: there is hardly any possibility of testing a theory as feeble as this.” Karl Popper, Unended Quest, an Intellectual Autobiography (London: Routledge, 1992 edition), 199

    or this:

    “The fact that the theory of natural selection is difficult to test has led some people, anti- Darwinists and even some great Darwinists, to claim that is a tautology. A tautology like “All tables are tables” is not, of course, testable; nor has it any explanatory power. It is therefore most surprising to hear that some of the greatest contemporary Darwinists themselves formulate the theory in such a way that it amounts to the tautology that those organisms that leave most offspring leave most offspring. And C. H. Waddington even says somewhere (and he defends this view in other places) that “Natural selection…turns out…to be a tautology”. However, he attributes at the same place to the theory an “enormous power…of explanation”. Since the explanatory power of a tautology is obviously zero, something must be wrong here.” Karl Popper “Natural Selection and the Emergence of Mind,” Dialectica, Vol. 32, Nos. 3-4, 1978, p339-355, 344.

    I know, Popper was not a biologist. How about Lewontin:

    “The concept of relative adaptation removes the apparent tautology in the theory of natural selection. Without it the theory of natural selection states that fitter individuals have more offspring and then defines the fitter as being those that leave more offspring; since some individuals will always have more offspring than others by sheer chance, nothing is explained. . . . Unfortunately the concept of relative adaptation also requires the ceteris paribus assumption, so that in practice it is not easy to predict which of two forms will leave more offspring.”

    Richard C. Lewontin, “Adaptation,” Scientific American 239 (September 1978): 166-67, 157-69.

    But, as Popper explained in the first quote, relative adaptation does not in fact remove the tautology problem.

    No one doubts that natural selection does in fact have some explanatory power at the microevolution level. Indeed, it has been observed. Nevertheless, as formulated by most Darwinists on a grand scale, the theory collapses into a tautology.

  14. BarryA,

    Natural Selection does not collapse into a tautology. It collapses because it has nothing of consequence to work on.

  15. Allen MacNeill actually tries to break natural selection into two different “neat” categories to fit the evidence that is consistently found in the fossil record (very sudden appearance, then rapid diversity, then slow decline in diversity over long periods of time.)

    His Quote :

    “However, once an evolving population reaches a state in which the mean phenotypic type has the highest relative fitness, then stabilizing selection replaces directional selection and the population stops changing significantly. This stasis then persists as long as the ecological niche of the stable population doesn’t change significantly.”

    Thus, his two different versions of natural selection become unfalsifiable. For they can explain both rapid diversification of a fossil type and then can explain lack of diversity of fossil type thereafter. He can explain anything he wants in the fossil record whenever he wants his theory to fit the evidence. i.e. his “new” theory has greater weight than the evidence has to falsify it.

    Whereas the ID/Genetic Entropy fits the evidence also and, unlike the evolutionary hypothesis of Macneil’s, is rigid enough to be falsifiable.

    To falsify ID/Genetic Entropy in the fossil record, just show a sudden sharp increase in diversity for an order or species after it has achieved maximum diversity in the fossil record. Once genetic entropy is in full swing for an order this sharp increase should never, ever occur since ID/Genetic Entropy holds that no new information can be created by natural processes since the “front loaded” information was introduced at the level of “parent” species or order.

  16. BarryA – yes, Popper was wrong. Here’s his mistake:

    Adaptation of fitness is defined by modern evolutionists as survival value and can be measured by actual success in survival:

    Fitness isn’t (or rather shouldn’t) be measured by actual success (or actually, lifetime reproductive success, LRS), it should be the mathematical expectation of LRS in the environment.

    For a fuller treatment of the argument, see Brandon (1978) Stud. Hist. Phil. Sci. 9: 181-206. (which I have as chapter 1 of this book).

    Bob

  17. H’mm:

    Bob, isn’t mathematical expectation in effect the sum of probabilities times specific outcomes across the set of possible outcomes?

    And, doesn’t that reduce to saying “on average,” the more fit population in a given time and space will survive and reproduce more often, thus, “fittest” is those who survive and reproduce more successfully?

    So far as I can see, that still ends up back at the point that on a population basis the more fit are the ones who are more successful at surviving and reproducing.

    In short, NS in the formulation RV + NS, from the view of dynamics involved, is a FILTER, not an innovator: at best it explains the survival [on average] — not the arrival — of the fittest. From the view of the logic, such an expectation formulation by and large [so far as it stands] IMHCO is in imminent danger of simply restating a tautology.

    This is very different from any notion of macro-evolutionary progress that implies spontaneous [chance + necessity only] information generation towards major body plan level innovation that is then rewarded by out-competing or opening up new zones of life habitation.

    In any case, it is worth noting that Johnson is far more nuanced and informed than you and others often suggest or infer, in his DOT.

    For instance, here is DOT, 1991, pp. 20 ff and p 160; on NS as tautology and the revisions to it that seek to avoid falling into it but too often revert unnoticed:

    [p. 20 ff ]Many of the most prominent neo-Darwinists have written at one time or another that natural selection is a tautology . . . In this formulation the theory predicts that the fittest organisms will produce the most offspring, and it defines the fittest organisms as the ones which produce the most offspring. It is important to document this point, because many Darwinists have convinced themselves that the tautology idea the tautology idea is a misunderstanding introduced . . . by creationists and other uncomprehending faultfinders . . . .

    JBS Haldane (1933): ” . . . the phrase , ‘survival of the fittest,’ is is something of a tautology. So are most mathematical theorems. There is no harm in saying the same truth in two different ways

    Ernst Mayr (1963)” . . . those individuals that have the most offspring are by definition . . . the fittest ones.”

    George Gaylord Simpson (1964): “Natural selection favors fitness only if you define fitness as leaving more descendants [. . .] To a geneticist fitness has nothing to do with helath, strength, good looks or anything but effect5iveness in breeding.”

    The explanation by Simpson . . . indicates why it is not easy to formulate the theory of natural selection other than by tautology . . . . we can presume a characteristic to be advantageous because a species which has it seems to be thriving, but in most cases it is impossible to identify the advantage independently of the outcome . . . All we can say is that the individuals which produced the most offspring must have had qualities required for producing the most offspring [he then discusses the case with Popper and his comments then the use of these by critics and the withdrawal of same under pressure] . . . .

    If the concept of natural selection were really only a tautology I could end the chapter at this point . . . But . . . [NS] can also be formulated in other ways that are not so easily dismissed. [He then looks at deductive formulations by Colin Patterson and Cairns-Smith, NS as scientific hypothesis (e.g. Futuyama), as philosophical necessity (National Academy of Science, US), and, for IMHCO good reason, finds them seriously wanting] . . . .

    [p. 160, research notes:]In raising the tautology issue I am not merely taking advantage of a few careless statements. When the critics are not watching, Darwinists continue to employ natural selection in its tautological form . . . The important point is that the Darwinists have been tempted continually by the thought that their theory could be given the status of an a priori truth, or a logical inevitability so that it could be known to be true without the need of empirical confirmation. Their susceptibility to this temptation is understandable. When the theory is stated as a hypothesis requiring empirical confirmation, the supporting evidence is not impressive. [Cf text for his reasons for that, and for onward references]

    I think that puts a very different colour on the matter at stake, and that we should now embark on a different tack in the discussion.

    GEM of TKI

  18. bornagain77:

    I’m confused. You wrote:

    To falsify ID/Genetic Entropy in the fossil record, just show a sudden sharp increase in diversity for an order or species after it has achieved maximum diversity in the fossil record.

    If you had an extensive fossil record of wolves and dogs but no DNA, wouldn’t that appear to falsify ID/GE by your criterion? How can you tell the difference?

  19. BarryA and kairosfocus:

    In light of Ms. O’Leary’s post about the Darwinistically-based rationizations from the political left (group selection) versus those from the political right (selfish gene):

    Something like a tautology must be in operation when — with equal facility and celerity — communists and fascists, racists and humanitarians, cold-hearted tax-the-poor free-market Republicans and gun-grabbin’ tax-and-spend big-government Democrats can all appeal to the same … what is it? … a theory? HA!

  20. Fitness isn’t (or rather shouldn’t) be measured by actual success (or actually, lifetime reproductive success, LRS), it should be the mathematical expectation of LRS in the environment.

    It almost sounds like you’re saying it shouldn’t be based upon reality but a mathematical model where Darwinism is made to work… ;)

    Joking aside, here is my earlier take on this subject along with the squirrels in another thread:

    Both the computer simulation AVIDA and biological evolution are instances of Darwinian processes. The only ingredients required for a Darwinian process are replication, heritable random variation, and fitness selection. In both, organisms are able to reproduce and pass their characteristics to their offspring. In both, random mutations arise which affect the organisms’ ability to survive and produce offspring. In both, selection pressures favor some varieties and penalize others.
    ….
    I think of fitness functions as a “funnel” that must be properly constrained in order to provide results. The design of this funnel must be balanced; it can either be too constrained or not constrained enough. The programmer’s goal is to find a balance by which the stated goal can be reached. In my opinion, there really isn’t such a thing as a “generic” GA program which can solve anything thrown at it–each program has to be designed to fit a purpose.
    ….
    Now all three models are Darwinian processes using replication, heritable random variation, and fitness selection. But only the third model is likely to produce any usable results since I’ve designed the environment and constraints with a goal.

    The implications of broad constraints in nature to the debate over ID should be clear. If a constraint is tightly controlled a desired result can be gained since only a certain portion of the search space, a target, is tried. Of course, in general the constraints set by nature are nothing like an optimal Chess GA program–nature’s constraints are typically very broad and the environment can change dramatically. At the same time an environment in nature can be so constrained that everything within it is eliminated. In nature there must be a balance for survival. An intelligently designed program would never set the constraints so narrowly that everything was eliminated. Nor would it set the constraints so broadly since the desired result would never be reached (that being close to a random search, the probability is not 0 but it’s at least highly implausible).

    I’ll give an example of why broad constraints are such an issue. Richard Dawkins explains the evolution of the bat wing in The Blind Watchmaker: A squirrel-like creature got a mutation that put a flap of skin in its armpit which aerodynamically helped break its fall when it tumbled out of a tree. Its friends without the mutated armpit flaps broke their necks and died when they fell out of trees. Bigger mutated flaps helped decelerate the creatures from higher altitudes, and so on until we have proper wings.

    Yes, he was dead serious. But the point is that he recognizes the further need for a narrower constraint since the general constraints defined by the environment wouldn’t help the development of wings. There needs to be a refinement of the fitness function, in this case elimination of squirrels which don’t have flaps of skin in their armpits. Of course, this story doesn’t take into account how often squirrels do indeed fall to their deaths…so this narrower constraint might be a very weak factor indeed.

    So the limitations we discover [about GA programs] should in principle extend to nature. And if it is the case that nature isn’t properly balanced in order to funnel the search as it appears to be then we have a very interesting bit of evidence.

    So…how many squirrels have to fall to their deaths for such a change to become fixated in the population? Do we have any data at all on deaths caused by falls or is it all speculation? The automatic tendon locking mechanisms of such creatures should keep most of the corpses of natural deaths up in the trees I would imagine. What environment would provide this selective pressure? In the other thread Hu claims that “Ordinary squirrels have been observed to fall from great heights with little or no injury.” So are we now forced to hypothesize a limited set of environments which may include trees that would regularly cause death by falling?

    The reason I ask all this is because evolutionary biology claims to have all this predictive power, so answering these questions should be easy. If this particular hypothesis (death by falling providing the environmental pressure) does not match reality what scenario is plausible? After all, there needs to some sort of plausible scenario since these traits are shared in divergent species and are supposed to be the result of convergent evolution.

    HOW TO MAKE A FLYING SQUIRREL: GLAUCOMYS
    ANATOMY IN PHYLOGENETIC PERSPECTIVE

    This recent article (2007) makes the suggestion that since leaping distance scales with size that a smaller species would benefit more from gliding. So perhaps the selective pressure would be a smaller species competing with a larger species? They also briefly mention that evolving from a ground-based ancestor would be unlikely, presumably because of the low positive selective pressure for gliding.

    Well, enough about NS. What mechanism for variation would provide squirrels gradually growing bushier tails and “pouchier” skin (as Dawkins quaintly simplified the differences)? Or would it be a mechanism that provides rapid variation? Unfortunately, this part of the problem apparently has not been considered that much yet according to that recent article, although “[a]s genetic analyses become less expensive and we approach the era of $1,000 genomes (Service 2006), it may become possible to document the molecular basis for the adaptations of flying squirrels and hence for the evolutionary novelty of gliding flight.” They do speculate:

    In a perspective titled ‘‘How to make a limb?’’ Duboule (1994) described the development of vertebrate limbs in terms of what was then known about Hox genes. The understanding of biochemical pathways of vertebrate development has increased greatly since then (Forlani et al. 2003) and should in the future enable us to determine what modifications in DNA have led to specific morphological changes during evolution. A selective review of the burgeoning literature leads us to suggest some biochemical pathways that may be responsible for the differences we have observed between flying squirrels and tree squirrels. These pathways are the links between the mutations of DNA and the adaptive morphological features of the phenotype that permit or facilitate the evolutionary novelty of gliding flight.
    ….
    During development, presomitic mesoderm gives rise to the somites, which then give rise to the vertebrae and skeletal musculature. The vertebral modifications we observe in the evolution of flying squirrels from tree squirrels are possibly driven by changes in the molecular pathways during these transitions, in particular Hoxa, Hoxc, and Hoxd, paralogs 10, 11, and perhaps 13 (Deschamps and van Nes 2005). Wellik and Capecchi (2003) demonstrated that Hoxa, Hoxc, and Hoxd 10 are active in the presomitic mesoderm of the lumbar region and determine that the lumbar vertebrae have no ribs, and that the paralogs Hoxa, Hoxc, and Hoxd 11 are active in the presomitic mesoderm of the sacral vertebrae and determine their morphology. Carapuco et al. (2005) suggest that Hoxa11 is active in the somites of the proximal caudal vertebrae as well.
    As the presomitic mesoderm gives rise to the somites, the boundaries between the somites appear to be controlled by the Notch pathway in a clocklike manner, under the coordination of the Wnt signaling pathway (Dequeant et al. 2006). The fibroblast growth factor (Fgf8 signaling pathway), coupled with the receptor for the fibroblast growth factor (Hajihosseini et al. 2004), is involved in determining the size of the somites (Aulehla and Herrmann 2004). A gradient of Fgf8 mRNA is established from the tail bud, which establishes a gradient of Fgf8, strongest toward the caudal end, weakest toward the rostral end (Dubrulle and Pourquie 2004), which determines the rate of inclusion of presomitic mesoderm in the somites as they are formed. This gradient, coupled with the timing of the somite boundaries by the Notch pathway, determines the size
    of the somites and could determine the size of the subsequently formed vertebrae. Another possibility is that the size differential between flying squirrel and tree squirrel vertebrae could be determined later in their embryology by different growth rates of the vertebrae, as described by Sears et al. (2006) for the phalanges in bat wings (discussed below). Because the embryology of tree and flying squirrels has not been studied, we cannot distinguish between these 2 possibilities.
    Boulet and Capecchi (2004) demonstrated that Hoxa11 and Hoxd11 are active in the forearm during the development of the radius and ulna, and that lack of function of these 2 leads to decreased mesenchymal condensation through reduced expression of Fgf8 and Fgf10 and delayed limb development. However, the major effect was the malformation of the growth plates of both bones. In the growth plates, the chondrocytes failed to mature and rarely formed hypertrophic cells. Thus, modifications of the biochemical pathways controlled by these 2 homeobox genes in the development of the forearm are likely the cause of differing adult forearm morphology in tree squirrels and flying squirrels.
    The Hox genes, Hoxa and Hoxd 11, 12, and 13 are similarly important in the development of the hands and feet, particularly through the expression of Fgf8 and Fgf10 (Boulet and Capecchi 2004; Zakany et al. 1997). Knosp et al. (2004) demonstrated that Hoxa13 is essential for the development of the digits of the hands and functions through the expression of the bone morphogenetic proteins Bmp2 and Bmp7. Delineation of the DNA changes in the evolution of flying squirrels, the molecular pathways affected, and how these have led to their morphology and made gliding flight possible, will ultimately tell us how nature has built flying squirrels. The evolutionary novelty of gliding has evolved 6 different times among Recent mammals, but squirrels probably present the only opportunity to study these details of the evolutionary process, because of the persistence of the ancestral morphology among the American tree squirrels.

    BTW, this type of variation “might” be front-loaded but in general I don’t see an issue with unguided Darwinian mechanisms being capable of making these particular changes considering their relative simplicity and apparent modularity. I just think it disconcerting that the focus of that recent article–which should represent the latest findings on this subject–seemed to be on making comparisons between samples. Darwinian mechanisms as the source of evolution were generally assumed to function, without any evidence of this being the case. The problems related to natural selection were never discussed in detail. This is ironic since the article is entitled “HOW To Make a Flying Squirrel”.

  21. Hu,

    I’m referring to deep time fossil records:

    http://www.sciencedaily.com/re.....142013.htm

    of special note:

    Extinct for 250 million years, trilobites once were the most common creatures in the world’s oceans.

    Webster has hunted trilobites from the northwest highlands of Scotland to the deserts of the American Southwest. He specializes in the olenellids, the oldest, most primitive trilobite group ever to evolve. The olenellids also show a great deal of variation within species.

    “That led me into thinking there’s something weird about these very primitive Cambrian trilobites that you don’t see in other ones,” he said.

    The only way to verify his hunch was to conduct an analysis that combined the data compiled in previously published reports. “It’s too much for one person to look at a thousand trilobite species,” Webster said.

    So for his Science study, Webster combed through 68 previously published studies of trilobites, searching for descriptions of evolving characteristics that could be incorporated into his analysis. After eliminating studies that were inappropriate for inclusion, 49 still remained.

    He focused on actively evolving characteristics. The trilobite head alone, for example, displays many such characteristics. These include differences in ornamentation, number and placement of spines, and the shape of head segments. His findings: Overall, approximately 35 percent of the 982 trilobite species exhibited some variation in some aspect of their appearance that was evolving. But more than 70 percent of early and middle Cambrian species exhibited variation, while only 13 percent of later trilobite species did so.

    “There’s hardly any variation in the post-Cambrian,” he said. “Even the presence or absence or the kind of ornamentation on the head shield varies within these Cambrian trilobites and doesn’t vary in the post-Cambrian trilobites.”

    I looked at Webster’s paper, and the evidence fits the ID/Genetic Entropy to a tee!

    Not good news for evolution Hu! Not good news at all for evolution!

  22. I think two different concepts have been conflated in the discussion about the ToE, by its proponents as well as its opponents, and that seems to explain at least some of the confusion. Both of them are characteristics of an individual.

    The first one, which I’d like to call potential fitness, is the expected value of the lifetime reproductive success (LRS) in the given environment, just as Bob said. It depends on the genotype of the individual, but not on any chance events during its lifetime. It’s a theoretical construct, impossible to measure directly, but one can study it statistically.

    The second one, actualized fitness, is just a synonym for LRS. That’s something directly observable, and it may be what the cited authors had in mind. It does lead to a tautology.

    The two concepts are NOT the same. For instance, consider peppered moths in an environment where trees are predominantly dark. Ignore, for simplicity, any other factors contributing to potential fitness than colour. Then every dark individual moth has a high potential fitness, but a non-negligible portion of them are unlucky and end up being eaten anyway. Conversely, every light-coloured moth has a low potential fitness, but many of them avoid predating birds by luck. So, the two concepts are different even on the population level.

    Regardless of the concept of fitness chosen, there is one necessary empirical condition for evolution: fitness is hereditary to some extent. (In the case of potential fitness, it’s almost tautological, but not quite.) However, sufficient conditions for long-term improvement to be likely are quite complicated.

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