Scott Turner

• Doctor of Philosophy
• Director at National Association of Scholars

Termites in the genus Macrotermes construct large-scale soil mounds above their nests. The classic explanation for how termites coordinate their labour to build the mound, based on a putative cement pheromone, has recently been called into question. Here, we present evidence for an alternate interpretation based on sensing humidity. The high humidi...

Nature has inspired generations of urban designers and planners in pursuit of harmonious and functional built environments. Research regarding self-organisation has encouraged urbanists to consider the role of bottom-up approaches in generating urban order. However, the extent to which self-organisation-inspired approaches draw directly from nature...

Large termite mounds, constructed by colonies of various species of macrotermitine termites (Isoptera, Termitidae, Macrotermitinae), are dominant features of the arid and semiarid savannas of southern Africa. These mounds can populate a savanna in very high densities, generally one to four colonies per hectare, containing biomass of termites and sy...

American landscape architect Ian L. McHarg developed an ecological planning theory and method for analyzing biophysical and sociocultural landscape characteristics and for evaluating these to determine suitable land uses. McHarg’s classic 1969 text, Design with Nature brought ecological planning to a mass audience, and his suitability analysis meth...

Macrotermes michaelseni and M. natalensis are two morphologically similar species occupying the same habitat across southern Africa. Both build large mounds and tend mutualistic fungal symbionts for nutrients, but despite these behavioural and physiological similarities, the mound superstructures they create differ markedly. The behavioural differe...

‘Brains’ may be considered to be computation engines, with neurons and synapses analogized to electronic components wired into networks that process information, learn and evolve. Alternatively, ‘brains’ are cognitive systems, which contain elements of intentionality, purposefulness and creativity that do not fit comfortably into a brain-as-compute...

Termite colonies construct towering, complex mounds, in a classic example of distributed agents coordinating their activity via interaction with a shared environment. The traditional explanation for how this coordination occurs focuses on the idea of a ‘cement pheromone’, a chemical signal left with deposited soil that triggers further deposition....

Termite colonies construct towering, complex mounds, in a classic example of distributed agents coordinating their activity via interaction with a shared environment. The traditional explanation for how this coordination occurs focuses on the idea of a "cement pheromone", a chemical signal left with deposited soil that triggers further deposition....

Studies of termite mound building have considered the mud they prepare, its properties and its composition. Here we consider the behaviors of the mound building termites Macrotermes michaelseni, (Sjostedt), in the presence of the viscous boundary layer (VBL), which spontaneously forms over any surface that air passes over. We looked how soil moistu...

The search for general common principles that unify disciplines is a longstanding challenge for interdisciplinary research. Architecture has always been an interdisciplinary pursuit, combining engineering, art and culture. The rise of biomimetic architecture adds to the interdisciplinary span. We discuss the similarities and differences among human...

Claude Bernard was the first to propose the concept of homeostasis. J. Scott Turner discusses the ongoing negotiation and mutual accommodation between parts of an organism—its many little lives.

How termite mounds function to facilitate climate control is still only partially understood. Recent experimental evidence in the mounds of a single species, the south Asian termite Odontotermes obesus, suggests that the daily oscillations of radiant heating associated with diurnal insolation patterns drive convective flow within them. How general...

We propose a novel computational method to extract information about interactions among individuals with different behavioral states in a biological collective from ordinary video recordings. Assuming that individuals are acting as finite state machines, our method first detects discrete behavioral states of those individuals and then constructs a...

Termites construct complex mounds that are orders of magnitude larger than any individual and fulfil a variety of functional roles. Yet the processes through which these mounds are built, and by which the insects organize their efforts, remain poorly understood. The traditional understanding focuses on stigmergy, a form of indirect communication in...

Many animals reside in burrows that may serve as refuges from predators and adverse environmental conditions. Burrow design varies widely among and within taxa, and these structures are adaptive, fulfilling physiological (and other) functions. We examined the burrow architecture of three scorpion species of the family Scorpionidae: Scorpio palmatus...

Termites of the genus Macrotermes are renowned for the large mounds they construct. This structure, which is built above the colony’s subterranean nest, is one of the most remarkable animal-built structures on the planet—remarkable both for its size (up to 11 m tall), and for its complex function. At one level, the mound is a superorganismal organ...

Darwinian evolution, as it was first conceived, has two dimensions: adaptation, that is, selection based upon “apt function”, defined as the “good fit” between an organism’s metabolic and biological demands and the environment in which it is embedded; and heredity, the transmissible memory of past apt function. Modern Darwinism has come to focus al...

Niche construction theory (NCT) has been represented as a new and comprehensive theory of evolution, one that breaks the constraints imposed by the dominant and largely gene-selectionist standard evolutionary model that is presently mischaracterized as “Darwinian.” I will argue that NCT is not so much a new theory, as it is a fruitful readmission o...

I consider the questions: what is an intelligent building, and what could make a building ‘intelligent’. The answer to this question turns on the more fundamental question: what is intelligence? I propose that two metaphors for intelligence are informative. On the one hand is intelligence through top-down engineered computation and code, what might...

The construction of termite nests has been suggested to be organized by a stigmergic process that makes use of putative cement pheromone found in saliva and recently manipulated soil ("nest material"), hypothesized to specifically induce material deposition by workers. Herein we tracked 100 individuals placed in arenas filled with a substrate of ha...

Burrows are common animal habitations, yet living in a burrow presents physiological challenges for its inhabitants because the burrow isolates them from sources and sinks for oxygen, carbon dioxide, water vapor and ammonia. Conventionally, the isolation is thought to be overcome by either diffusion gas exchange within the burrow or some means of c...

Rodent burrows are often assumed to be environments wherein the air has a high concentration of CO2. Although high burrow [CO2] has been recorded, many studies report burrow [CO2] that differs only slightly from atmospheric concentrations. Here, we advocate that one of the reasons for these differences is the penetration into burrows of air gusts (...

The architects of the Modern Synthesis viewed development as an unfolding of a form already latent in the genes. However, developing organisms play a far more active, constructive role in both their own development and their evolution than the MS proclaims. Here we outline what is meant by constructive processes in development and evolution, emphas...

The intermittent incubation of an egg imposes costs on the parent in both time and energy. Heretofore, time and energy costs in intermittent incubation have tended to be considered separately, in part because no suitable theoretical framework has existed to describe how time and energy interact in the intermittent warming of an egg by a brood patch...

Through most of the twentieth century, biology’s image as a valid science has been gauged by how closely it adheres to the norms of “objective” sciences like physics, chemistry and mathematics. Strains of biological thought that depart from this norm are deemed non-scientific. This presumes that life is fundamentally a physical, chemical and thermo...

The biological and philosophical implications of the emergence of new collective individuals from associations of living beings. Our intuitive assumption that only organisms are the real individuals in the natural world is at odds with developments in cell biology, ecology, genetics, evolutionary biology, and other fields. Although organisms have s...

In modern evolutionary theory, selection acts on particular genes and assemblages of genes that operate through phenotypes expressed in environments. This view, however, overlooks the fact that organisms often alter their environments in pursuit of fitness needs and thus modify some environmental selection pressures. Niche construction theory intro...

Architects' view of nature tends to rest on the assumption that it is inherently efficient in its use of materials and energy, and essentially ingenious and elegant in its solutions. This perception in science is one that has been propounded through Darwinism: the notion that refinement of ‘design’ is achieved through repetitive selection, variatio...

Eusociality has evolved independently at least twice among the insects: among the Hymenoptera (ants and bees), and earlier among the Isoptera (termites). Studies of swarm intelligence, and by inference, swarm cognition, have focused largely on the bees and ants, while the termites have been relatively neglected. Yet, termites are among the world’s...

Termites and the structures they build have been used as exemplars of biomimetic designs for climate control in buildings, like Zimbabwe's Eastgate Centre, and various other "termite-inspired" buildings. Remarkably, these designs are based upon an erroneous conception of how termite mounds actually work. In this article, we review recent progress i...

The harmonious melding of structure and function - biological design - is a striking feature of complex living systems such as tissues, organs, organisms, even superorganismal assemblages like social insect colonies or ecosystems. How designed systems come into being remains a central problem in evolutionary biology. The prevailing explanation for...

Large termite mounds, constructed by colonies of various species of macrotermitine termites (Isoptera, Termitidae, Macrotermitinae), are dominant features of the arid and semi-arid savannas of southern Africa. These mounds can populate a savanna in very high densities, generally one to four colonies per hectare, containing biomass of termites and s...

he savannas of southern Africa are dotted with the spectacular mounds of the fungus- growing termites of the genus Macrotermes (Termitidae: Macrotermitinae). These mounds can reach several meters high and represent a colos- sal engineering project for the termites that build them (Fig. 1). The mound is a respiratory device, built to cap- ture wind...

Gaia's most remarkable prediction is a biosphere- level physiology and all the organismal traits that implies, including global homeostasis. Gaia's most formidable challenge is to explain how such properties can emerge from the welter of competing genetic interests which the biosphere comprises. This article explores the problem of "emergent homeos...

Phenotype, whether conventional or extended, is defined as a reflectionof an underlying genotype. Adaptation and the natural selection thatfollows from it depends upon a progressively harmonious fit betweenphenotype and environment. There is in Richard Dawkins' notion ofthe extended phenotype a paradox that seems to undercut conventionalviews of ad...

Organism-built structures have long been useful artifacts for students of evolution and systematics, because they represent a permanent record of a set of behaviors. These structures also represent an investment of energy by an organism, and to persist in the fossil record, the energetic investment in the structure must pay off for the organisms th...

Patterns and rates of air movements in the mounds and nests of Macrotermes michaelseni were studied using tracer methods. Wind is a significant source of energy for powering nest ventilation, despite the mound being a completely enclosed structure. Nests are ventilated by a tidal movement of air driven by temporal variation in wind speed and wind d...

The mounds of Macrotermes michaelseni (Sjöstedt) in northern Namibia have a characteristic architecture, being divided into three structurally distinct components: a central cone-shaped mound, topped by a tall, thin spire which tilts northward at an angle similar to the sun's average zenith angle, and a broad outwash pediment that results from eros...

Eggs of intermittently incubating birds are periodically rewarmed by a transient pulse of heat from the parent's brood patch. Estimating the energy cost of rewarming such an egg requires knowledge of the egg's thermal capacity, typically assumed to be the product of the egg's mass and its specific heat, designated here as the gravimetric thermal ca...

Odontotermes transvaalensis is a subterranean macrotermitine common in the arid grasslands of north-western South Afria. These termites build a conspicuous above-ground chimney that meets the structural requirements of an induced-flow system for ventilating the colony. Pulses of tracer gas flow from ground-level entry holes into the colony and out...

Chicken eggs subjected to a sinusoidally varying input of heat from a brood patch experience sinusoidally varying egg temperatures. As the embryo matures, steady and transient egg temperatures become more uniform, declining about 0.8° C at the brood patch and increasing from 0. 4° to 0. 8° C in the more peripheral regions of the egg. The increasing...

1.1. Intermittently incubated eggs are alternately warmed by the brood patch during nest visits and allowed to cool during absences from the nest.2.2. The thermal energetics of such eggs are not governed by conventional measures of thermal energetics, like thermal conductance or thermal resistance, which only measure the steady-state component of h...

1.1. Evaporative water loss rates from the isolated spittle of the pine spittlebug, Aphrophora Saratoga, were measured and compared to evaporation rates from free water surfaces.2.2. Water evaporated from isolated spittle at an average rate of 2.77 μg/sec, compared to an average rate of 8.08 μg sec− cm −2from a free water surface, a reduction of ab...

Seothyra henscheli (Eresidae) is a burrowing spider that lives in the dune sea of the southern Namib Desert, Namibia. Prey capture by these spiders involves a foray from a cool subterranean retreat to the undersurface of a capture web that can be lethally hot. Striking, disentangling and retrieving prey from the capture web typically involves sever...

Onymacris unguicularis (Coleoptera: Tenebrionidae) is black, while Onymacris bicolor is mostly white. Body color affects only one avenue of heat exchange - absorption of direct shortwave and visible radiation. Of all the factors that affect beetle temperature, the most important is convection heat loss. Of lesser importance, but still significant a...

I incubated chicken eggs using an artificial brood patch, which enabled me to measure the energy required to keep chicken eggs, 16–19 days old, warmer than the ambient air. To keep brood patch temperature (i.e. at the egg surface-brood patch interface) 9.4°C warmer than the ambient air, living chicken eggs require on average 541 mW, of which 403 mW...

1. Late prenatal chicken embryos in eggs injected with saline showed a feeble homeothermic metabolic response to gradual cooling. This response was absent in thiourea-treated eggs. This suggests that the incipient homeothermic metabolic response before paranatal life may be attributed to thyroid development. 2. The compensatory metabolic response d...

1.1. Prior to around day 18 of incubation, chicken embryos are apparently poikilothermic. No compensatory increase of metabolic rate is evident when the embryo is gradually cooled.2.2. At about day 18 of incubation, a weak metabolic response to egg cooling appears.3.3. After external pipping, the metabolic response to gradual cooling is stronger. T...

1.1.It is widely supposed that thermal conductance scales to body size by a power equation of the form C = aMb.2.2.It is theoretically unrealistic to expect the scaling of thermal conductance to follow a power relation, because animals exchange heat in multiple ways, each of which varies with body size in a different way.3.3.I have developed models...

1. In a helium atmosphere, heat is dissipated from a surface 3.5 times faster than it is in air. Eggs in a helium-oxygen atmosphere cool only 1.4 times faster than they cool in air. This signifies that internal resistance to heat flow is a significant factor in the cooling rates of eggs. 2. Heat flow occurs inside an egg in two ways: by conduction...

Studies of the heating and cooling rates of ectotherms usually report only a time contant for temperature change. This implies that the transient temperatures of ectotherms behave like a first-order physical system. However, the transient temperatures of ectotherms may behave more like an overdamped second-order system. Reporting only a single time...

At the start of incubation, heat flows through the egg by conduction only. During incubation, the embryo's developing circulation should augment conduction in the egg, distributing heat from the brood patch more uniformly through the egg. The augmentation of heat flow through the egg should be very small in small eggs, but should be larger in large...

For blood flow to be an effective agent for the control of heat exchange, it must occur in a region of the body where conduction resistance in the tissues is relatively high, and in an environment where external resistance to heat exchange is relatively low. If either of these conditions is not met, control of heat exchange by blood flow is not pos...

1.1. For cylinders or spheres smaller than a critical size, a layer of insulation may increase, rather than decrease, the rate of heat exchange.2.2. It has been suggested that the critical size for animals insulated with fur or feathers is about 4–7 g body mass, and therefore may explain why many small mammals and birds are born naked. We suggest t...

The swimming speed of alligators, like the locomotory speeds of many ectotherms, is significantly affected by temperature. However, temperature also affects alligators' swimming behavior. The effect of temperature on swimming speed appears to be partly the result of direct effects of temperature on muscle performance and effects of temperature on s...

The resistance to heat transfer of birds' eggs scales not to the power of egg mas, as would be expected for an isomorphic object, but to the −0.60 power. This unexpected exponent apparently is the result of the composite resistance to heat exchange by both radiation and convection.

1.1.|The ratio of rates of heating and cooling in American alligators in maximum at a body mass of about 5 kg.2.2.|There may be an optimum body size for the control of heat exchange by blood flow in American alligators.

Through his imaginative work on the thermal biology of reptiles, Raymond B. Cowles fomented a revolution in thought on the biology of temperature. In this article, I review the development of Raymond Cowles' work on temperature, and show how much of its originality can be attributed to a remarkable theory on the extinction of the dinosaurs.

Small American alligators (200-400 g) were heated and cooled from 20 to 35 to 20 C in a temperature-controlled wind tunnel. Blood flow to the limbs and tail was periodically occluded, using remotely controlled occlusion cuffs. When blood flow in all appendages was occluded, the rate of heating was significantly reduced from that when blood flow was...

The pineal complex may be a part of the sensory and central neural system controlling thermoregulatory behavior. The pineal and parapineal organs of some ectotherms appear to function as radiation dosimeters, regulating exposure to sunlight. Physiological thermoregulation may be influenced by the pineal complex through cardiovascular adjustments or...