Science Literature

The Laetoli trackways from Tanzania were first reported in 1979 and immediately attracted attention because they provided evidence of bipedalism. The tracks were preserved in volcanic ash dated at 3.6 million years. Many at the time thought they looked exactly like human footprints, but few of the researchers were willing to adopt this interpretation. The debate has been extensive and inconclusive, but some positive leads have recently been published. Evidence is now available to answer the question: did the makers of the trackways walk like humans or like apes?

"In particular, debates over the origins and evolution of bipedalism revolve around whether early bipeds walked with energetically economical human-like extended limb biomechanics, or with more costly ape-like bent-knee, bent-hip (BKBH) kinematics. If early hominins used a BKBH gait, then we must account for the persistence of an energetically costly form of bipedal walking until the evolution of the genus Homo."

The Laetoli trackways (Credit: John Reader/Photo Researchers Inc., source here)

Research in the US involved human subjects walking with different gaits over damp sandy ground. The BKBH gait changes the way the body weight is carried by the feet and this, in turn, affects footprint morphology. Each footprint was recorded with a 3D scanner and quantitative comparisons were made.

"We compared footprints made by subjects walking with a normal, extended limb gait, and with a bent-knee, bent-hip (BKBH) ape-like gait at their preferred speeds with sand water content of 6-8%. These substrate conditions match those of Laetoli, which are described as similar to damp, fine to medium grained sand. We also examined the effects of increased speed and increased substrate moisture (10-12% water) on footprint morphology. We tested the hypothesis that a BKBH gait alters body weight transfer and produces significantly different footprint morphology than an extended limb gait."

The findings were unambiguous. There are significant differences between true bipedal tracks and BKBH tracks - and the Laetoli data is definitely bipedal.

"The relative toe depths of the Laetoli prints show that, by 3.6 Ma, fully extended limb bipedal gait had evolved. Thus, our results provide the earliest unequivocal evidence of human-like bipedalism in the fossil record."

Meanwhile, research in Belgium has been concerned with the more fundamental question as to whether any useful information can be gained from human-like trackways. The researchers were aware of many variables affecting trackway morphologies: the shape of the foot, the mechanical properties of the foot, its kinematics, its kinetics, and the mechanical properties of the substrate.

"[W]e experimentally generate footprints and quantify a selection of relevant subject-dependent and kinesiological variables that might influence the topology of a footprint, left behind in a granular substrate. Analysis will provide a better insight into the information that can (or cannot) be deduced from footprints."

This is a cautious and critical approach, and justifiably so. Their analyses confirmed the complex nature of footprint generation, and they found no unique variable that "determines" the morphology of a footprint. Mistakes have been made.

"For instance, the "obvious" transfer of weight along the lateral margin of the foot is taken as an argument for well-established bipedalism, but it is also observed in chimpanzees and bonobos, although a medial transfer of pressure along the metatarsal heads is not often evident in apes. When focusing on footprints alone (without detailed knowledge of foot anatomy, as is often the case in paleoanthropology) even the footprints of these apes may be falsely interpreted as made by bipeds with a well-developed longitudinal arch."

Having said this, the research did document cross-correlations between the different kinesiological factors investigated. This is where valid and useful information can be expected to be extracted from fossil trackways. This is the kind of information that was obtained in the US research.

"With these precautions in mind, we argue that different zones of a footprint do contain information on several kinesiological aspects of gait. Future research into footprint formation, soil mechanics and hominin foot morphology and locomotion should further increase insight in the causal relationship between these factors."

So how does this impact our understanding of the Laetoli footprints? It allows us to conclude, with greater confidence than before, that the trackways were generated by bipeds. At very least, the pendulum has swung so that the burden of proof now rests on those who would question the bipedal interpretation. This creates a problem for those who are trying to construct an evolutionary pathway for Homo sapiens - because bipedalism has to occur early in the story. Australopithecus afarensis is the primary candidate for making the tracks, but evidence is accumulating that bipedalism was not a characteristic of this ape (for more, go here). The US researchers acknowledge an uncertainty problem: "While our results show that Laetoli hominins walked with human-like kinematics, we still cannot be sure of which hominin taxon made the footprints." They concentrate their thoughts on adaptation: supposedly driven by the reduced energy requirements of a fully bipedal primate.

"Hypotheses for the origins of bipedalism often focus on selection for energy economy in early hominins. Energetic hypotheses are based on the reduced locomotor costs of humans compared to apes walking with BKBH gaits, and therefore, compared to ape-like pre-hominin ancestors."

This adaptationist approach falls foul of the integrated nature of the changes that are needed for an ape to walk upright. These changes affect the feet bones, the leg length, the pelvis, the way the spine attaches to the pelvis and particularly the skull, the vision system, the balance system, and more. This cannot be a single-factor transformation under selection pressure. The adaptive landscape has a steep-sided mountain separating apes and man - and there is no tunnel through the mountain! The implication is that humans walked at Laetoli, and that the textbook stories of human evolution will have to be re-written.

Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics
Raichlen DA, Gordon AD, Harcourt-Smith WEH, Foster AD, Haas WR Jr
PLoS ONE, March 2010, 5(3): e9769. doi:10.1371/journal.pone.0009769

Abstract: Debates over the evolution of hominin bipedalism, a defining human characteristic, revolve around whether early bipeds walked more like humans, with energetically efficient extended hind limbs, or more like apes with flexed hind limbs. The 3.6 million year old hominin footprints at Laetoli, Tanzania represent the earliest direct evidence of hominin bipedalism. Determining the kinematics of Laetoli hominins will allow us to understand whether selection acted to decrease energy costs of bipedalism by 3.6 Ma.
[. . .] These results provide us with the earliest direct evidence of kinematically human-like bipedalism currently known, and show that extended limb bipedalism evolved long before the appearance of the genus Homo. Since extended-limb bipedalism is more energetically economical than ape-like bipedalism, energy expenditure was likely an important selection pressure on hominin bipeds by 3.6 Ma.

Experimentally generated footprints in sand: Analysis and consequences for the interpretation of fossil and forensic footprints
K. D'Aout, L. Meert, B. Van Gheluwe, D. De Clercq, P. Aerts
American Journal of Physical Anthropology, 2010, 141(4), 515-525.

Fossilized footprints contain information about the dynamics of gait, but their interpretation is difficult, as they are the combined result of foot anatomy, gait dynamics, and substrate properties. We explore how footprints are generated in modern humans. Sixteen healthy subjects walked on a solid surface and in a layer of fine-grained sand. In each condition, 3D kinematics of the leg and foot were analyzed for three trials at preferred speed, using an infrared camera system. Additionally, calibrated plantar pressures were recorded. After each trial in sand, the depth of the imprint was measured under specific sites. When walking in sand, subjects showed greater toe clearance during swing and a 7 degrees higher knee yield during stance. Maximal pressure was the most influential factor for footprint depth under the heel. For other foot zones, a combination of factors correlates with imprint depth, with pressure impulse (the pressure-time integral) gaining importance distally, at the metatarsal heads and the hallux. We conclude that footprint topology cannot be related to a single variable, but that different zones of the footprint reflect different aspects of the kinesiology of walking. Therefore, an integrated approach, combining anatomical, kinesiological, and substrate-mechanical insights, is necessary for a correct interpretation.

Scientists with an interest in developing design concepts and principles found in the natural world are not instinctively attracted by exhortations to expel design from Biology. However, developing a coherent academic framework that does justice to the design principles being studied has not attracted the attention it deserves. Consequently, many scholars in this field have absorbed views developed by people with a rather different agenda for design. McIntosh recognises there is a problem here, and sets out to provide an alternative perspective.

"Many have taken the view that design is only an illusion in living systems, arguing that such 'apparent design' and accompanying complexity can be explained by the neo-Darwinian paradigm. [. . .] However, [. . .] the inference to original design and intelligence is a perfectly valid alternative from direct analogy to designs within the man-made world."

An essential aerodynamic surface: barbules in one direction have hooks whereas in the other direction the barbules are ridge-like. (Source here)

After providing an overview of different types of feather, McIntosh develops an argument based on "specified functional complexity". There is a multifunctioning and multi-optimisation in feather construction - characteristics that apply to both modern and to fossil feathers - which is said to be "consistent with the design thesis".

"There are the features which are immediately apparent such as aerodynamic loading and the material construction of rachis and barbs to sustain this. However, there are also more subtle features such as the arrangement of hooks and barbules primarily for keeping the feather together, such that they prevent air from going through them during the downstroke but allowing some air to pass through in the upstroke, thus maximising the efficiency of energy use in wing flap. The keratin itself has an extremely high specific strength, and the shape of the filament cross sections used in rachis construction moves from near circular near the root to a curved and ribbed rectangular shape away from the root for structural efficiency under bending and potentially buckling loads."

Although enough has been said already to associate pennaceous feathers with the concept of irreducible complexity, further aspects of a holistic system emerge with consideration of the uropygial (preening) gland at the base of its spine. Hypotheses about the evolution of these feathers involving unintelligent causation have totally failed to provide credible scenarios.

"The ability to reach this gland is a feat of twisting which a bird performs with ease. However, it raises serious issues concerning the supposed evolution of feathers, since it is necessary for the feather construction (barbule ridge and hook system) to arise concurrently with the preening gland and the ability to manoeuvre the neck a full 180 degrees. None of the fossil evidence shows any evidence of such transitions."

The author elaborates on the crucial importance of functional information and the failure of current evolutionary speculations. The hooks and ridges of barbules are clear examples. These barbules have opposite characteristics: "hooks on one side of the barb and ridges on the other so that adjacent barbs become attached by hooked barbules from one barb attaching themselves to ridged barbules from the next barb. [. . .] It is that vital network of barbules which is necessarily a function of the encoded information (software) in the genes. Functional information is vital to such systems." This leads to a discussion of research into pattern formation, primarily to show that the origin of functional information has not been solved (or even addressed).

"However, correct and enlightening as these models are, it is important to recognise that this is not the same as functional information, where coded instructions are involved, first, in the precise ordered arrangement of nucleotides in DNA, and, secondly, in the multifunctioning construction of items from these codes such as hooked and ridged feather barbules. This is a subject of a separate paper by the author where the argument is made that all living systems have coded machinery which sits on high free energy bonds, all of which have to be in place for the system to work."

The second part of the paper develops the same style of argument for the avian lung: the organ must be considered as an integrated system if it is to be understood as functioning machinery, and a "bottom-up" blind watchmaker approach totally fails to explain the evidence for functional information.

"Science can study the effect on the natural world of systems of pre-existing material, but it cannot preclude the possibility of intelligence extraneous to that very matter and energy being involved in its formation. To say otherwise is effectively wedding science to a narrow philosophical foundation. [. . .] Once one opens the possibility that intelligence is involved, the evidence leads very naturally to the conclusion of design, not by going against the known empirical laws (such as gravity [. . .]), but precisely the reverse. We must keep to the 'nullius in verba' motto of the Royal Society ('on the words of no one'), and not preclude from the outset where the evidence may lead."

This paper provides a helpful contribution to the development of multiple hypotheses in science. It deserves to be widely read and analysed by students of science.

Evidence of design in bird feathers and avian respiration
A. C. McIntosh
International Journal of Design & Nature and Ecodynamics, Vol 4, Issue 2, (2009) 154-169.

This paper explores the evidence for design in living systems. In particular, it considers two of the mechanisms used in bird flight. These include feathers and the remarkable counterflow mass exchanger breathing system used in the avian lung system. Both systems are examples of the principle of specified functional complexity, which occurs throughout nature. There is no known recorded example of this developing experimentally where the precursor information or machinery is not already present in embryonic form. Such design features indicate non-evolutionary features being involved.

Anyone attempting to swat a fly will become aware of its remarkable aerodynamic capabilities. Its speed of response and ability to change direction abruptly far exceed our own powers as pursuers. The flight of insects has received considerable attention from researchers and some recent work was stimulated by the recognition of a gap in knowledge. The scientists realized that the previously-studied flight control system involving vision cannot be the explanation for how flies maintain stability in the face of unpredictable short disturbances.

"Corrective behavior often takes advantage of vision. For fruit flies, however, reaction time to visual stimuli is at least 10 wingbeats, so these insects must employ faster sensory circuits to recover from short time-scale disturbances and instabilities."

To study how fruit flies recover from in-flight disturbances, researchers glued magnetic pins to the insects' backs and zapped them with a magnetic field. This fly has a 1.5 mm pin on its back and is held in place by the tip of a sewing needle. (Credit: Wang, Cohen and Guckenheimer labs, Source here)

The experimental work required the research team to abandon ideas of tethering insects or imposing other restrictions on flight behavior. They needed to observe insects in free-flight.

"To probe this fast control strategy, we devised an experimental method that imposes impulsive mechanical disturbances to flying insects while allowing us to measure relevant aspects of flight behavior. We first glue tiny ferromagnetic pins to fruit flies and image their free flight using three orthogonally oriented high-speed video cameras. When a fly enters the filming volume, an optical trigger detects the insect, initiates recording, and activates a pair of Helmholtz coils that produce a magnetic field. The field and pin are both oriented horizontally, so the resulting torque on the pin reorients the yaw, or heading angle, of the insect. We then use a new motion tracking technique to extract the three-dimensional body and wing motions."

What they observed is that prior to the perturbation (which lasted 5ms, or about one wingbeat period), the wings beat symmetrically. After the magnetic torque was applied, 3 wingbeats were needed for the control system to respond, and then "asymmetries in the wing motions appear for about five wingbeats, indicating the insect is actively generating corrective torque". For small perturbations, the insects correct "nearly perfectly", whereas larger perturbations - although corrected to some extent - lead to permanent changes in heading.

"The accuracy of the recovery indicates that a refined control strategy underlies the response of fruit flies to in-flight perturbations. To reveal this strategy, we construct a physics-based model of the observed behavioral response."

Body motions are detected by the halteres: "small vibrating organs [. . .] that act as gyroscopic sensors. Anatomical, mechanical, and behavioral evidence indicates that the halteres serve as detectors of body angular velocity that quickly trigger muscle action." With this model, the halteres have a nonlinear response consistent with vibratory gyroscopes, so sensor saturation explains "why fruit flies are unable to accurately recover from strong perturbations". The control system design principles are as follows:

"These findings suggest that these insects drive their corrective response using an autostabilizing feedback loop in which the sensed angular velocity serves as the input to the flight controller. [. . .] [T]he velocity is sensed by the halteres, processed by a neural controller, and transmitted by the flight motor into specific wing motions that generate aerodynamic torque."

Halteres are remarkable organs and unique to the Diptera. The research raises questions about other autostabilization techniques found in the natural world and how such systems can be incorporated into flying robots.

"Flight control principles uncovered in this model organism may also apply more broadly, and this work provides a template for future studies aimed at determining if other animals employ flight autostabilization. The control strategies across different animals are likely to share common features, because the physics of body rotation is similar across many animals during flapping-wing flight. Additionally, animals that lack halteres may use functionally equivalent mechanosensory structures such as antennae. Finally, the control architecture of the fruit fly offers a blueprint for stabilization of highly maneuverable flapping-wing flying machines."

These design principles were incorporated by intelligent agents into aeroplanes very early in their history (further information is here). It is now apparent that flying insects got there first! In evolutionary terms, we have here a good example of convergence. Since these control systems represent complex specified information (with the greater complexity found in the insect control system), intelligent agency should be invoked in both cases.

"For fixed-wing machines, the need to overcome instabilities spurred the invention of autostabilizing systems by 1912, only 9 years after the Wright brothers first manually controlled airplane flight. The development of such automatic steering systems also led to the first formal description of proportional-integral-derivative control schemes and advanced gyroscopic sensor technology. The fruit fly's autostabilization response is well-modeled by a simple PD scheme that receives input from gyroscopic halteres, and, like airplanes, uses fine adjustment of wing orientation to generate corrective torques. Roughly 350 million years after insects took flight, man converged to this solution for the problem of flight control and joined animals in the skies."

Discovering the flight autostabilizer of fruit flies by inducing aerial stumbles
Leif Ristroph, Attila J. Bergou, Gunnar Ristroph, Katherine Coumes, Gordon J. Berman, John Guckenheimer, Z. Jane Wang and Itai Cohen.
Proceedings of the National Academy of Sciences, 2010, 107:4820-4824 | doi:10.1073/pnas.1000615107

Abstract: Just as the Wright brothers implemented controls to achieve stable airplane flight, flying insects have evolved behavioral strategies that ensure recovery from flight disturbances. Pioneering studies performed on tethered and dissected insects demonstrate that the sensory, neurological, and musculoskeletal systems play important roles in flight control. Such studies, however, cannot produce an integrative model of insect flight stability because they do not incorporate the interaction of these systems with free-flight aerodynamics. We directly investigate control and stability through the application of torque impulses to freely flying fruit flies (Drosophila melanogaster) and measurement of their behavioral response. High-speed video and a new motion tracking method capture the aerial "stumble", and we discover that flies respond to gentle disturbances by accurately returning to their original orientation. These insects take advantage of a stabilizing aerodynamic influence and active torque generation to recover their heading to within 2 deg in less than 60 ms. To explain this recovery behavior, we form a feedback control model that includes the fly's ability to sense body rotations, process this information, and actuate the wing motions that generate corrective aerodynamic torque. Thus, like early man-made aircraft and modern fighter jets, the fruit fly employs an automatic stabilization scheme that reacts to short time-scale disturbances.

See also:

Tyler, D. Biorobotics casts light on the way insects fly, ARN Literature blog (22 February 2007)

The mollusc, known as the scaly-foot gastropod, has been known for about a decade. It was discovered living in the deep sea near the Kairei Indian hydrothermal vent field on the Central Indian Ridge. The natural environment for the animal is harsh. There are extremes of temperatures, high pressures and high acidity levels that can easily damage shells of calcium carbonate. Brachyuran crabs live in the vicinity and these "are known to compress gastropod mollusc shells between their chela" with loads of up to 60N.

"To understand how the valiant gastropod holds up to these trials, Christine Ortiz of MIT and her colleagues used nanoscale experiments and computer simulations to dig in to the shell's structure. Many other species' shells exhibit what Ortiz calls "mechanical property amplification," in which the whole material is hundreds of times stronger than the sum of its parts."

The scaly-foot gastropod uses a unique trilayered shell to protect itself from hazards. (Image credit: Anders Waren, Swedish Museum of Natural History. Source here)

Most exoskeletal structures are technically known as multilayered composites. The parameters are the layer thicknesses, the nano- and microstructure of each layer, the number of layers, the sequence of layers, etc. Each species appears to have its own resultant profile.

"Design, inspired by nature, of engineering materials with robust and multifunctional mechanical properties [i.e., those which sustain a variety of loading conditions] is a topic of major technological interest in a variety of civilian and defense applications. Here, we identify the design principles of the shell of a gastropod mollusc from a deep-sea hydrothermal vent [order Neomphalina, family Peltospiridae, species Crysomallon squamiferum]. This system has a trilayered structure unlike any other known mollusc or any other known natural armor, with a relatively thick compliant organic layer embedded between two stiffer mineralized layers, an outer iron sulfide-based layer and an inner calcified shell."

The outer layer is about 30 micrometres thick and is mineralised: it contains iron sulphide particles (greigite, Fe2S4). This gastropod is the only metazoan known to employ iron sulphide as a skeletal material. The middle layer is about 150 micrometres thick and is thought to be the periostracum (the template for shell mineralization, providing protection against corrosive and dissolutive marine environments, and also chemical protection from boring organisms). The inner layer is composed of aragonite that is itself layered:

"[It] possesses a gradient layer [. . .] with a typical crossed lamellar layer (CLL) microstructure (approximately 50 [micro]m thick), followed by a relatively thick layer also with a CLL microstructure (approximately 200 [micro]m thick, followed by a thin prismatic layer (PL) on the inner surface of the shell (approximately 1.5 [micro]m thick)."

This structure has been studied empirically and modelled. Simulations were performed to understand how the shell responds to impacts and applied loads. There are too many details to document here.

"It is interesting to see how C. squamiferum has created these additional different protection mechanism compared to other gastropod molluscs by using materials plentiful and specific to the deep-sea hydrothermal vent environment, i.e., vent fluids rich in dissolved sulfides and metals.
The design principles of the trilayered shell of C. squamiferum exhibit many aspects that are different from the highly calcified shells of typical gastropod molluscs or any other natural armor. Each material layer serves distinct and multifunctional roles leading to many advantages."

Design principles have emerged from this research. The authors have found new design features leading to enhanced functional performance. "Each material layer serves distinct and multifunctional roles leading to many advantages". They point out that design principles are extremely important because there are so many variables: "The design space for synthetic multilayered structural composites for protective applications is enormous". The great merit of biological systems is that they provide a chart to steer through this space. However, the authors attribute design in biological systems to an "evolutionary process".

"Biological systems, such as the one described here, greatly reduce the engineering design space since efficient threat-protection design concepts have emerged through the lengthy evolutionary process that fulfill the necessary functions and constraints."

The problem with this evolutionary framework is that it has no empirical validity. We have no warrant for explaining design principles via evolutionary processes. The authors explain that they do not know whether the observed design "represents an advanced functional adaptation as an antipredatory response or an exaptation (i.e., a trait that evolved to serve one function, but subsequently and simultaneously may serve other functions)". This comment is, unfortunately, entirely typical of the culture prevailing in science produced by philosophical materialism. Evolutionists have supreme confidence in their theoretical framework, but do not seem to see the need to constrain theory by reference to empirical data. Observed adaptations do not demonstrate the emergence of design concepts. The only sources of design concepts that we know of are intelligent agents. Replacing the culture of materialism by one that integrates information inputs with physics and chemistry is long overdue.

With this alternative culture, paragraphs like the following take on a new richness of meaning:

"In particular, the efficient natural armor structural system described here sustains both mechanical loading, as well as thermal fluctuations with inherent mechanisms to prevent catastrophic failure. The multimaterial, trilayer design and advantageous curved geometry enables structural stiffening, reduction of radial displacements, penetration resistance, and stability during thermal impulses even with the presence of large mismatches between constituent materials. Trilayered sandwich composite designs have had limited use in military applications, and the concepts reported here could lead to bioinspired improvements and broader applicability and improved performance for human, vehicle, and structural armor."

Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod
Haimin Yao, Ming Dao, Timothy Imholt, Jamie Huang, Kevin Wheeler, Alejandro Bonilla, Subra Suresh, and Christine Ortiz
Proceedings of the National Academy of Sciences, January 19, 2010, vol. 107, no. 3, 987-992 | doi:10.1073/pnas.0912988107

Abstract: Biological exoskeletons, in particular those with unusually robust and multifunctional properties, hold enormous potential for the development of improved load-bearing and protective engineering materials. Here, we report new materials and mechanical design principles of the iron-plated multilayered structure of the natural armor of Crysomallon squamiferum, a recently discovered gastropod mollusc from the Kairei Indian hydrothermal vent field, which is unlike any other known natural or synthetic engineered armor. We have determined through nanoscale experiments and computational simulations of a predatory attack that the specific combination of different materials, microstructures, interfacial geometries, gradation, and layering are advantageous for penetration resistance, energy dissipation, mitigation of fracture and crack arrest, reduction of back deflections, and resistance to bending and tensile loads. The structure-property-performance relationships described are expected to be of technological interest for a variety of civilian and defense applications.

See also:

Grossman, L. Snail In Shining Armor, Science News, February 13th, 2010; Vol.177 #4 (p. 13)

Spider silk has been an active area for biomimetics research for several years. Spinoff companies have been launched in anticipation of commercial gains. However, despite the enthusiasm and commitment of research staff, the prizes are still elusive. Whilst the main goal is to produce fibres that are as strong and as flexible as spider silk, there are other aspects of the natural material that have attracted the interest of researchers. One of these concerns the ability of webs to be a site for dew collection.

"When Lei Jiang first observed the phenomenon, he was intrigued. "How does that happen?" he wondered. After all, he says, "if you took a human hair, water would not stick to it like that". His initial curiosity led to an almost five-year-long study. The findings could have implications for the design of materials for water collection and for the efficiency of chemical reactions."

Spider silk manipulates water with skill (source here)

Not only do webs attract dew, the droplets are able to hang stably on the silk fibres. This suggests the presence of a microstructural mechanism. All polymeric fibres have a microstructure and spider silk is no exception. SEM images reveal a series of amorphous regions (called puffs) and crystalline regions (called joints). The nanofibrils are highly hydrophilic: enhancing wettability and favourable for condensing dew. The puffs have a very open structure and are semi-transparent in images. However, when water starts to condense, the puffs shrink - first to "opaque bumps" and then to "spindle-knots". As they shrink, tiny water droplets coalesce to form larger drops with movement from joints to spindle-knots.

"Further work revealed that movement of the droplets towards the knots is directed by two forces acting together: the force generated by a gradient of surface energy on the fibrils and the one produced by the spindle shape of the knots. "This is quite different from other reported surfaces, on which drops are driven just by individual forces," says Jiang."

These findings are stimulating human invention. The research paper reports success with nylon filaments that are coated with a hydrophilic material that dries in tiny knots similar to those found in spider silk. The goal now is to produce something of commercial value.

"These observations clearly show that our artificial spider silk not only mimics the structure of wet-rebuilt spider silk but also its directional water collection capability. We therefore anticipate that the design principles uncovered and implemented in this study will aid the development of functional fibres for use in water collection and in liquid aerosols filtering in manufacturing processes."

Why does the spider produce a web with dew-gathering potential? "The researchers are unsure of why the spider has evolved to possess this ability. "It could be for its drinking activities, or it could be to refresh the web structure to make it stronger and stickier for prey," Jiang told physicsworld.com." Magdalena Helmer wrote a short News & Views piece on "Dew catchers", saying: "spiders don't need to look for water because the silk fibres that they spin are highly efficient at collecting it from moist air". However, direct evidence of functionality is lacking. There is considerable scepticism that spiders make any use of dew-gathering.

"But Fritz Vollrath, who studies spider silk at Oxford University in the UK, disagrees with Jiang's theory. He thinks spider silk has to be dry to function. 'If I am correct, then the authors are studying an artefact, which is still interesting, although it has no biological function,' says Vollrath. [. . .] Brent Opell, a spider expert at Virginia Tech in Virginia, US, is equally cautious about the results, although he says the experimental work is sound. 'The implication that [capture] threads have evolved to harvest moisture is not the view of most arachnologists,' he says."

Is there an ID perspective on this? Wherever researchers recognise "design principles" in the natural world, the answer is, of course, 'yes'. The presumption with ID is that design features imply functionality, whether or not we know the details. Dew gathering is a unique and remarkable feature of spider silk simply because other fibres do not display such behaviour. The authors comment:

"We observed such directional water collection behaviour only with wetted silk fibres (that is, wet-rebuilt silk) from the cribellate spider Uloborus walckenaerius; in contrast, silkworm silk and nylon fibres with a uniform structure did not exhibit the directional water collection phenomenon."

Whether evolutionists can explain 'how the spider came to gather dew' is more uncertain. Even with functionality identified, perfecting this highly engineered system makes it most reasonable to infer intelligent, rather than natural, causation.

Directional water collection on wetted spider silk
Yongmei Zheng, Hao Bai, Zhongbing Huang, Xuelin Tian, Fu-Qiang Nie, Yong Zhao, Jin Zhai & Lei Jiang
Nature, 463, 640-643 (4 February 2010) | doi:10.1038/nature08729

First paragraph: Many biological surfaces in both the plant and animal kingdom possess unusual structural features at the micro- and nanometre-scale that control their interaction with water and hence wettability. An intriguing example is provided by desert beetles, which use micrometre-sized patterns of hydrophobic and hydrophilic regions on their backs to capture water from humid air. As anyone who has admired spider webs adorned with dew drops will appreciate, spider silk is also capable of efficiently collecting water from air. Here we show that the water-collecting ability of the capture silk of the cribellate spider Uloborus walckenaerius is the result of a unique fibre structure that forms after wetting, with the 'wet-rebuilt' fibres characterized by periodic spindle-knots made of random nanofibrils and separated by joints made of aligned nanofibrils. These structural features result in a surface energy gradient between the spindle-knots and the joints and also in a difference in Laplace pressure, with both factors acting together to achieve continuous condensation and directional collection of water drops around spindle-knots. Submillimetre-sized liquid drops have been driven by surface energy gradients or a difference in Laplace pressure, but until now neither force on its own has been used to overcome the larger hysteresis effects that make the movement of micrometre-sized drops more difficult. By tapping into both driving forces, spider silk achieves this task. Inspired by this finding, we designed artificial fibres that mimic the structural features of silk and exhibit its directional water-collecting ability.

Making the paper: Lei Jiang
Nature, 463, 586 (4 February 2010) | doi:10.1038/7281586a

Abstract: Spider silk structure holds secret to catching water as well as flies.

See also:

Birch, H. How spider silk soaks up water, Chemistry World (3 February 2010)

Dacey, J. Spider web inspires fibres for industry, physicsworld.com (3 February 2010)

Helmer, M. Dew catchers, Nature, 463, 618 (4 February 2010) | doi:10.1038/463618a

Two research psychologists have contributed an Opinion paper based on the empirical finding "that individuals presented with unfamiliar moral dilemmas show no difference in their responses if they have a religious background or not". The data used was obtained from an online web questionnaire which is open to any volunteer participants (including myself). Findings are reported elsewhere and in their Opinion paper the authors provide only a summary:

"These studies, carried out using the web-based Moral Sense Test (http://moral.wjh.harvard.edu/), recruit thousands of male and female subjects, with educational levels that range from elementary school to graduate degrees, with political affiliations that range from liberal to conservative, and religious backgrounds that range from devout to atheist. In each of these studies, subjects read and judged the moral permissibility of an action on a 7pt-Likert scale [. . .]. Each scenario presented a contrast between a harmful action and a significant benefit in terms of lives saved."

Moral dilemmas come in all shapes and sizes (source here)

The hypothetical scenarios in the test present dilemmas where actions that are evidently harmful to human life considered in isolation result in significant benefits to other humans (whose lives are saved). The generalized results are as follows:

"More specifically, in dozens of dilemmas, and with thousands of subjects, the pattern of moral judgments delivered by subjects with a religious background do not differ from those who are atheists, and even in cases where we find statistically significant differences, the effect sizes are trivial."

This conclusion is the anchor-point for the author's wide-ranging discussion of the origin of morality and, as indicated in their title, the origin of religion. In evaluating their paper, we need to consider whether their empirical starting point is robust enough to carry such far-reaching conclusions.

Some caution is needed in the way "religious background" is understood. There is no systematic probing of the concept in the web-based questionnaire. Participants have to select a label that best fits their current religion, the religion of their upbringing, and locate themselves on the spectrum of "not-at-all" religious to "very" religious. This is all pretty superficial and subjective, given the diversity of religious experience around the world. There is no attempt to use Likert scales to assess the degree to which respondents understood God to be a creator, transcendent, immanent, able to answer prayer or, even more relevant, the reference point for our sense of right and wrong. Consequently, the term "religious" is 1-dimensional and almost devoid of content. Yet, the authors place considerable weight on their analysis of responses gathered.

More caution is needed when we read in the above quote about "trivial" effect sizes. In another study the authors mention, radical altruism was the focus of interest: does religious background affect thinking about whether to sacrifice ones own life "in order to save the lives of a greater number of anonymous others". Significant differences were found. But these could be predicted, say the authors, "given the fact that many religions praise martyrdom". They go on to offer this analysis:

"[A]lthough there are significant evolutionary pressures against such acts of radical altruism, religious pressures might lead people to offer this judgment because they believe it is the morally appropriate answer. What religion can do, and what political and legal institutions can do as well, is alter local and highly specific cases. And yet, they appear to have no influence at all on the intuitive system that operates more generally, and for unfamiliar cases."

These comments about the need for caution are intended to show that the authors have a very inadequate view of the concept of "religion". To them, the various religions can all be lumped together and there are no distinctions worth making. They do not see the need to explain why they think that radical altruism can somehow be linked to the praise of martyrdom. Even when differences are discernable between the moral judgments of the religious and those of atheists, they are considered trivial apparently because there are (untested) evolutionary explanations of why the religious are so minded. All this raises questions about the adopted methodology and the analysis of the authors.

Before making further comments on the arguments built on the empirical findings, it is useful to note some comments by Philip Ball, writing a column for Nature. He draws attention to the conceptual framework underpinning the research: "By taking it as a given that religion is an evolved social behaviour rather than a matter of divine revelation, [the authors' paper] tacitly adopts an atheistic framework." Ball is absolutely right, and we can add the thought that tacit atheism is a pervasive problem in many areas of scholarly activity. Given their presuppositions, no one should expect the authors to reach a conclusion that challenges atheism. However, this does not mean such conclusions cannot be drawn by others who approach the same data with a different conceptual framework.

The first thesis developed in the paper is that "moral intuitions operate independently of religious background" and are therefore not explained by religion. The authors develop an analogy with linguistics, where the concept of innate ability for language acquisition is widely held, and this innate ability is independent of the cultural background. Ball describes this thesis in this way:

"The paper [ . . ] challenges the assertion commonly made in defence of religion: that it inculcates a moral awareness. If we follow the authors' line of thinking, religious people are no more likely to be moral than atheists."

Whenever there is only one hypothesis on the table, there should be concern! Scholars should be cultivating multiple working hypotheses and looking for ways of testing them. To show the significance of an alternative conceptual framework, consider a perspective that understands mankind as made in the image of its Designer. Innate abilities are imparted by this Designer: we speak because the Designer speaks; we have a moral awareness because the Designer is the reference point for what is right and what is wrong. These innate abilities affect all people - whether they are atheists or religious, whether they are pantheists or theists, whether they are male or female, young or old. This is a hypothesis that explains the data and scholars who "tacitly adopt[] an atheistic framework" are excluding this alternative purely on ideological grounds.

The second thesis is concerned with the origin of religion. The authors think their work on moral intuitions leads naturally to the hypothesis that religion is a by-product of pre-existing capabilities.

"Specifically, recent work in moral psychology supports the view that religion evolved as a cognitive by-product of pre-existing capacities that evolved for non-religious functions."
[. . .]
"Religion is a set of ideas that survives in cultural transmission because it effectively parasitizes other evolved cognitive structures."
[. . .]
"Here again, religion stands on the shoulders of cognitive giants, psychological mechanisms that evolved for solving more general problems of social interactions in large, genetically unrelated groups."

For the purposes of this blog, we shall defer comment and let Philip Ball speak: "Whether it [i.e. the research] 'explains' religion is another matter."

"It's debatable, however, whether these moral tests are probing religion or culture as a moral-forming agency, because non-believers in a predominantly religious culture are likely to acquire the moral predispositions of the majority. Western culture, say, has long been shaped by Christian morality. [. . .] But to uncover religion's roots, is morality necessarily the best place to look? It seems hard to credit the idea that the immense cultural investment in religion was made merely to strengthen and fine-tune existing neural circuits related to morality. [. . .] Yet attempting to explain the origins of such a rich cultural phenomenon as religion is doomed to some extent to be a thankless task. For to 'explain' Chartres Cathedral or Bach's Mass in B Minor in terms of non-kin cooperation is obviously to have explained nothing."

The origins of religion: evolved adaptation or by-product?
Ilkka Pyysiainen and Marc Hauser
Trends in Cognitive Sciences, 14(3), 104-109, March 2010 | doi:10.1016/j.tics.2009.12.007

Abstract: Considerable debate has surrounded the question of the origins and evolution of religion. One proposal views religion as an adaptation for cooperation, whereas an alternative proposal views religion as a by-product of evolved, non-religious, cognitive functions. We critically evaluate each approach, explore the link between religion and morality in particular, and argue that recent empirical work in moral psychology provides stronger support for the by-product approach. Specifically, despite differences in religious background, individuals show no difference in the pattern of their moral judgments for unfamiliar moral scenarios. These findings suggest that religion evolved from pre-existing cognitive functions, but that it may then have been subject to selection, creating an adaptively designed system for solving the problem of cooperation.

Morals don't come from God
Philip Ball
Nature, 8 February 2010 | doi:10.1038/news.2010.55

Abstract: The finding that religion scarcely influences moral intuition undermines the idea that a godless society will be immoral, says Philip Ball. Whether it 'explains' religion is another matter.

See also:

Morality Research Sheds Light on the Origins of Religion, ScienceDaily (9 February 2010)

Hunter, C. Important New Paper on Evolutionary Explanation, Darwin's God (8 February 2010)