Intelligent Design

Design principles in the feather

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Before biomimetics, there was little interest in studying biological materials to gain inspiration for human invention. This is because researchers assumed that living things originated via “blind watchmaker” mechanisms. Since most researchers had discarded any thoughts of intelligent agency, it seemed only natural to think that living things would not help the human quest for improved or innovative designs. However, this stance has been almost completely replaced by a much more positive perspective. Somehow the “blind watchmaker” has morphed into an immensely skilled craftsman. Now it is realized that life forms display structures with design elegance, the watchmaker is considered to behave as though he is not only sighted, but also astoundingly intelligent.

“Biological materials such as the feather are hierarchically organised and intimately constructed such that the final design makes it difficult to separate the parts or their functions from the whole.” [. . .]
“Many biological systems have mechanical properties that are far beyond those that can be achieved using the same synthetic materials with present technologies. As Ashby et al. (1995) show, it is not so much the material properties of the components as their arrangement within the natural composites which give rise to the exceptional multifunctional properties.” (p.324)

The avian feather, mentioned in the above quote, is a case in point. Scholars have started by assuming simplicity and this has led to the under-estimation of hierarchical organization. Four years ago, Lingham-Soliar and co-authors reported work based on the hypothesis that the “mechanical structural organization of the rachis was hierarchical” and that this structure would be revealed if the unstructured matrix material surrounding the beta-keratin fibres could be removed. They managed to achieve matrix removal by a process of degradation using fungi. The emerging model of the structure has three zones, fully supporting the hypothesis (plus the foam-filled centre of the rachis, which acts as an energy absorber),

“These findings of Lingham-Soliar et al. (2010) refuted a previous contradictory claim that the beta-keratogenic tissue of the rachis and barbs was fully characterized ultrastructurally by histodifferentiation, i.e. the bulk of the rachis, calamus, and barb rami were comprised of typical, tile-like, stratified squamous epithelial tissues.” (p.325)
[. . .] “We now know, with the discovery of a cross-fibre system in the epicortex of the barbs and rachis, that the feather microfibre structure is far more complex than previously thought and highly anisotropic.” (p.333)

In the paper reviewed here, Lingham-Soliar summarises previous work before showing how these new insights into feather structure increase our understanding of functionality and performance. He refers to the feather as “a classic example of bioengineering”. Taking the fracture mechanics of feathers as his starting point, the discussion covers: (1) crack-stopping, (2) stiffness, ductility and buckling, (3) torsion and flexion, and (4) ductile tearing. These findings feed into the conclusions. A relevant excerpt is below.

“In the feather, the cross-fibre architecture may provide a key mechanism for preventing damage to the rachis and barbs. However, a rigid system risks being loaded with dangerously high forces during flight. In this context, it is noteworthy that the longitudinal fibre system of the cortex not only provides stiffness but, in contrast to the cross-fibre system of the epicortex, importantly, allows torsion, which would help to lower the critical bending moment needed to cause local buckling failure. At the core of this understanding is the presence of two distinctive fibre systems, that of the epicortex and of the cortex, which in given circumstances will inevitably function in synergy to promote ideal feather aerodynamics. The potential for future biomechanical discussions are clear.” (p.333)

Having heard (earlier this year) Gareth Dyke speak on aspects of his research, I was particularly interested in Lingham-Soliar’s critique of his view (co-authored with Robert Nudds, published in Science) that Archaeopteryx was incapable of flapping flight because its feathers could not cope with the stresses and strains that flapping imposes. Lingham-Soliar draws on his own biomechanical analysis and concludes that Nudds and Dyke’s approach is flawed:

“Unfortunately, the rhetoric involved in the claims by Nudds and Dyke that their method over others is “quantitative” rather than “subjective”, and that they are supported by the laws of physics, is contradicted by faulty science, feather structural knowledge and mechanical analyses. Nudds and Dyke’s calculations ignore a major component of the feather rachis, the foam core, and also make use of a formula that is inappropriate – the calculations have little quantitative basis with respect to real feather structure and lack statistical significance, given they are based on a bird sample number of 1.” (p.334)

We should note that Lingham-Soliar’s critique has received a response from Palmer (2014), to which a reply has been prepared (Lingham-Soliar, 2014).

There is a tension in this paper between the appeal to “millions of years of biological evolution [that] have produced efficient materials and structures” and the avian fossil record that these structures appeared abruptly and in a mature form. (This is one reason why feather evolution has been relocated to the theropod dinosaurs). Lingham-Soliar finds himself using teleological language to describe what he sees:

“Biological structures, e.g. the feather, have developed even more ‘cunning’ methods for increasing the “work of fracture”.” (page 328)
[Fibre scientists have developed materials to absorb and dissipate large amounts of energy before failure], “Yet, this was achieved in a natural material, beta-keratin in the feather of birds, specifically in the structure of the rachis – in both conditions, i.e. increased fibre bundle thickness and an interfacial polymer matrix or “glue” – remarkably some 150 million years earlier.” (page 331)

We can respectfully point out that the evidence-base for such statements is profoundly weak. Many textbooks make similar statements but do not get beyond Darwinism when discussing mechanism. But Darwinism is a theory built primarily on the philosophy of naturalism. The evidences supporting it relate to ecology, not to the origins of complexity. We can predict that while naturalism reigns supreme, these tensions will stay with us. What we would like to see is a culture of academic freedom for dissenting views, particularly avenues of research relating to intelligent design.

Feather structure, biomechanics and biomimetics: the incredible lightness of being
Theagarten Lingham-Soliar
Journal of Ornithology, April 2014, Volume 155, Issue 2, 323-336 | DOI: 10.1007/s10336-013-1038-0

Millions of years of biological evolution have produced efficient materials and structures that are a source of inspiration to engineers. The paper reviews the overall design principles in the feather rachis and elaborates upon recent functional interpretations. It concentrates on recent findings that shed new light on feather microstructure and on how keratin fibres in a protein matrix are arranged in intricate ways to achieve specific combinations of stiffness and strength on the one hand and flexibility and elasticity on the other. This includes the syncitial barbule cells of the rachis and barb cortex, the crossed-fibre architecture of the epicortex (lateral walls of the cortex), and the foam-like structure of the medullary pith. Discussion of the biomechanics of feather microstructure uses engineering principles for a better understanding of the functional ramifications. Further research is proposed with respect to feather micro- and macrostructure in trying to expand our knowledge on bird flight, behaviour and ecology in different species. The discussion also considers the validity of a study purporting to use quantitative methods and engineering principles to show that the iconic fossil bird Archaeopteryx was incapable of flapping flight.

See also:

Palmer, C. Response to Lingham-Soliar: Feather structure, biomechanics and biomimetics: the incredible lightness of being. Journal of Ornithology, online July 2014 | doi:10.1007/s10336-014-1090-4

Lingham-Soliar, T. Response to comments by C. Palmer on my paper, Feather structure, biomechanics and biomimetics: the incredible lightness of being. Journal of Ornithology, online June 2014 | DOI: 10.1007/s10336-014-1093-1

Nudds, R.L. & Dyke, G.J. Narrow Primary Feather Rachises in Confuciusornis and Archaeopteryx Suggest Poor Flight Ability, Science, 14 May 2010: Vol. 328, 887-889 | DOI: 10.1126/science.1188895

29 Replies to “Design principles in the feather

  1. 1
    rhampton7 says:

    Please correct me if I’m wrong, but ID theory implies that the flight feather must be the original form and non-flight feathers only form some time afterward due to loss of primary function and/or genetic degradation. But the fossil record shows an emergence of complex forms over time, and flight not original function of the first feathers.

  2. 2
    Mung says:

    rhampton7, yes, you’re wrong.

  3. 3
    Joe says:

    I concur with Mung.

  4. 4
    rhampton7 says:

    Please explain.

  5. 5
    Mung says:

    Please educate yourself about ID.

    rhampton7 @ 1:

    …the flight feather must be the original form and non-flight feathers only form some time afterward due to loss of primary function and/or genetic degradation.

    How and why is this implied by ID theory?

  6. 6
    Joe says:

    ‘Cuz the designer only likes birds that can fly. Duh. Page 2157 of “An EvoTARD’s View of Intelligent Design”.

  7. 7
    Joe says:

    David Tyler:

    Before biomimetics, there was little interest in studying biological materials to gain inspiration for human invention.

    When did biomimetics originate? It had to be a long time ago because people have been trying to fly because they watched birds fly, ie they tried to copy birds. Or is that not a form of biomimetics?

  8. 8
    rhampton7 says:

    Mung,

    Complex specified information can not arise through a step-wise process – ergo it must originate de novo fully formed and fully functional. Do you disagree? The flight feather is such an example. And because nature can not gain new, functional information without an intelligent designer, the only natural variations we should expect to see are those that occur through the loss of information/function. Thus feathers used for decoration or insulation should appear only after flight feathers.

  9. 9
    Mung says:

    rhampton7:

    Complex specified information can not arise through a step-wise process – ergo it must originate de novo fully formed and fully functional. Do you disagree?

    As a sometimes programmer, every program I write arises by a step-wise process. Yes, I disagree.

    Shall we debate then whether software programs are complex specified information, or can we agree that thy are?

  10. 10
    rhampton7 says:

    Mung,

    I didn’t premise my initial comment on your opinion, but on what ID theory predicts.

    Besides, step-wise refers to the accumulation of complexity by adding to existing functional forms. So your analogy only holds if, while programming the equivalent of a flight feather, every step you complete during the sequence results in a functional program.

  11. 11
    Mung says:

    rhampton7:

    I didn’t premise my initial comment on your opinion, but on what ID theory predicts.

    You asked a question and I answered it.

    You haven’t established yet what it is that ID theory predicts, or as you said earlier, what it implies.

    I assumed the question you posed to me was intended to help establish that, not that it was a rhetorical question to which you already knew the answer.

    So no you’ve added another aspect to your original thesis:

    Please correct me if I’m wrong, but ID theory implies that the flight feather must be the original form and non-flight feathers only form some time afterward due to loss of primary function and/or genetic degradation. But the fossil record shows an emergence of complex forms over time, and flight not original function of the first feathers.

    ID theory implies this because complex specified information can not arise through a step-wise process – ergo it must originate de novo fully formed and fully functional.

    Step-wise refers to the accumulation of complexity by adding to existing functional forms. So your analogy only holds if, while programming the equivalent of a flight feather, every step you complete during the sequence results in a functional program.

    You’re still wrong.

    And you’re begging the question while also contradicting yourself.

    If ID allows for specified complexity to be built up gradually then it doesn’t follow that ID theory implies that the feather must first appear fully formed.

    Again, software development. Software programs don’t just magically appear fully formed. They are built up via a sequence of steps. Are you going to assert that they are not intelligently designed because they are built up in steps?

  12. 12
    rhampton7 says:

    Mung,

    ID theory, at least espoused by Dembski & Behe, does not allow for specified complexity to be built up gradually. That is nature climbing mount improbable. i.e. evolution building the bacterial flagellum in a step-wise process.

  13. 13
    Mung says:

    rhampton7 @ 12:

    Earlier (@ 10) you intimated that specified complexity could be built up step by step as long as each step was functional.

    Are you retracting that claim now, or asserting that it wasn’t in reference to specified complexity?

  14. 14
    rhampton7 says:

    What I said was that each step resulted in a functional program, but that’s not how programming works.

    To be more clear: When writing a function, the first line doesn’t result in making the entire program functional but in breaking it, because a function that isn’t closed will create an error – regardless of the state of the code in contains.

    That’s the argument Behe makes with the bacterial flagellum. Some types of designs – very complex ones – require too many parts to be fitted together simultaneously to be functional. It can’t be built up step by step by nature or design because it’s irreducible.

  15. 15
    Joe says:

    Irreducible complexity can be built up step-wise by design. Engines are IC and they are built step-wise by design. I would say all man-made IC systems, structures and events are built up step-wise.

    A properly written genetic algorithm could easily construct a flagellum in a step-wise fashion.

  16. 16
    rhampton7 says:

    Joe,

    After completing each step is the engine/bacterial flagellum functional as an engine/bacterial flagellum? No. That’s the point.

  17. 17
    Mung says:

    As we see, rhampton7, you’re just begging the question.

    Plus, you’re wrong, again. This time about IC systems.

    Take the icon of an IC system, the mousetrap. Does Behe evev claim the mousetrap has to be “poofed” together all at once to be IC? Where? Does it ever claim a mousetrap cannot be built gradually? Where?

    Your level of understanding about ID is pathetic. You should be embarrassed. Please take my advice @ 5.

  18. 18
    rhampton7 says:

    Mung

    Please read Irreducible Complexity: The Challenge to the Darwinian Evolutionary Explanations of many Biochemical Structures;

    As a simple example of irreducible complexity, Behe presents the humble mousetrap.

    Shown above is a modified sketch of Behe’s mousetrap as taken from http://www.arn.org/docs/mm/mousetrap.htm.

    It contains five interdependent parts which allow it to catch mice: the wooden platform, the spring, the hammer (the bar which crushes the mouse against the wooden base), the holding bar, and a catch. Each of these components is absolutely essential for the function of the mousetrap. For instance, if you remove the catch, you cannot set the trap and it will never catch mice, no matter how long they may dance over the contraption. Remove the spring, and the hammer will flop uselessly back and forth-certainly not much of a threat to the little rodents. Of course, removal of the holding bar will ensure that the trap never catches anything because there will again be no way to arm the system.

    Now, note what this implies: an irreducibly complex system cannot come about in a gradual manner. One cannot begin with a wooden platform and catch a few mice, then add a spring, catching a few more mice than before, etc. No, all the components must be in place before it functions at all. A step-by-step approach to constructing such a system will result in a useless system until all the components have been added. The system requires all the components to be added at the same time, in the right configuration, before it works at all…

    In fact, Michael Behe asserts that the complicated biological structures in a cell exhibit the exact same irreducible complexity that we saw in the mousetrap example. In other words, they are all-or-nothing: either everything is there and it works, or something is missing and it doesn’t work. As we saw before, such a system cannot be constructed in a gradual manner-it simply won’t work until all the components are present, and Darwinism has no mechanism for adding all the components at once. Remember, Darwin’s mechanism is one of gradual mutations leading to improved fitness and survival. A less-than-complete system of this nature simply will not function, and it certainly won’t help the organism to survive. Indeed, having a half-formed and hence non-functional system would actually hinder survival and would be selected against.

  19. 19
    Vishnu says:

    Obviously all IC structures are not poofed into existence. Each IC structure in your body was built by a sequential process during ontogeny. It’s the origin of that sequential process which is problem for the “dirt worshipers” to explain.

  20. 20
    rhampton7 says:

    Mung, Vishnu,

    First, “poof” is not a fair assessment, as ID theory does not make an effort to determine the process(es) involved in the origin of a design.

    Second, while the bacterial flagellum can be built, it can not originate from a series of lesser designs. There is no gradual precursor to the bacterial flagellum. From No, Avida Has Not Falsified Irreducible Complexity;

    In Climbing Mount Improbable, Richard Dawkins developed the metaphor of Mount Improbable. Evolution is only capable of climbing up gradual slopes. It cannot climb cliffs. What Avida demonstrates is that given a gradual slope, Darwinian processes are capable of climbing it. What irreducible complexity claims is that irreducible complex systems are surrounded on all sides by cliffs. Notice the distinction. Avida says that evolution can climb gradual slopes. Irreducible complexity claims that there are no gradual slopes. Avida is about what we can do with the gradual slopes, and irreducibly complexity is about whether or not the slopes exist. Avida provides no evidence that gradual slopes exist, it just assumes that they do. What Avida demonstrates is simply beside the point of the claim of irreducible complexity.

  21. 21
    Joe says:

    rhampton7- You miss the point. In a design scenario there isn’t any requirement for a fully functional structure at every step.

    And although ID is not about the specific process, nothing prevents people from trying to figure that out. But just how are we supposed to determine how something that we cannot design and construct was designed and constructed? We have a hard enough time trying to figure out how the ancients pulled off some of the stuff they built.

  22. 22
    rhampton7 says:

    Joe,

    The point is that there are “cliffs” such that you can’t reach certain designs by gradual building on top of previous designs. From Irreducible Complexity and the Evolutionary Literature:
    Response to Critics

    The second and more important point is that, while the paper is very interesting, it doesn’t address irreducible complexity. Either Miller hasn’t read what I said in my book about metabolic pathways, or he is deliberately ignoring it. I clearly stated in Darwin’s Black Box metabolic pathways are not irreducibly complex (Behe 1996) (pp. 141-142; 150-151), because components can be gradually added to a previous pathway. Thus metabolic pathways simply aren’t in the same category as the blood clotting cascade or the bacterial flagellum.

  23. 23
    Mung says:

    rhampton7:

    First, “poof” is not a fair assessment, as ID theory does not make an effort to determine the process(es) involved in the origin of a design.

    ID theory does not then imply that the flight feather had to appear before other types of feathers, nor that it had to be the “original form,” nor that non-flight feathers “only form some time afterward due to loss of primary function and/or genetic degradation.”

    See my post @ 2.

    And we’re back where we started.

  24. 24
    Mung says:

    rhampton7 @ 18,

    A poorly written article, imo.

    In intelligently designed complex systems, every step in building up the system does not have to produce a system that has the final function and may even include steps that provide no new function at all.

  25. 25
    rhampton7 says:

    Mung,

    The premise is that flight feathers are designed because the complexity they exhibit can not have arisen naturally, gradually. However previous forms do exist and do show an increase of complexity with time, adding new functions while preserving past functions. In other words, it’s a gradual slope and not a cliff. I suggest that flight feathers are like metabolic pathways and not like the bacterial flagellum. In this particular case, evolution remains a valid explanation.

  26. 26
    rhampton7 says:

    Viable intermediates” is the term Behe uses. Irreducible complexity systems, by (his) defintion have none.

    To illustrate irreducible complexity, Behe uses a mousetrap. Each component of the mousetrap, the hammer, the base, the spring, the catch, etc., are all required for it to function; without any one of those components, the mousetrap doesn’t work. Like the bacterial flagellum, Behe argues, it is extraordinarily unlikely that a gradual evolution of various mousetraps could occur, since natural selection requires viable intermediates.

  27. 27
    Upright BiPed says:

    The physical demands of translation (the very thing that drives the organization of all living systems) has pushed the ID concept of Irreducible Complexity beyond any rational challenge.

    Interested persons may choose to argue whether a particular system is IC, but challenges to the reality of IC itself is not sustainable.

  28. 28
    Mung says:

    Natural selection requires “viable” intermediates.

    Intelligent design doesn’t.

    Not that I have a clue what a “viable” intermediate flight feather might be look like, nor a “non-viable” intermediate feather for that matter.

  29. 29
    Joe says:

    Yes rhampton7- engines have cliffs too. That means they are not accessible for purely materialistic processes.

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