B

Figure 8.9 Use of the limbs of Potamodytes as hydrofoils to accelerate water above and to the center of the bubble. a As viewed from the side, the tibiae of the beetle are in position to impart an upward acceleration to water flowing past the beetle. b As viewed from the top, the tibiae are held at acute angles to the body. In this position they impart a centripetal acceleration to water flowing past the beetle. Figure 8.9 Use of the limbs of Potamodytes as hydrofoils to accelerate water above...

Cd Oo

Figure 5A.1 Schoute's model for arborescent growth of corals. a A Schoute tree results when branching occurs at the tips of a growing branch. b A representative Schoute tree growth of the coral Lobophyllia corymbosa. After Dauget (1991) of trees, each named after the botanist who formulated it, and these seem to explain a considerable part of the variation of growth among corals. The simplest is known as Corner's model and is characterized by simple linear growth at the tip. In a coral, the...

O

Figure 8.4 Conversion of a bubble to a gill. a Fluxes of oxygen and nitrogen in a bubble attached to an insect that is consuming oxygen. b For oxygen in a bubble attached to an insect, the characteristic curve of pO2(b) is not as described in Figure 8.3. At first pO2(b) pO2(s) and oxygen diffuses into the water. But for a short while pO2(b) < pO2(s), as indicated by the shaded area (where oxygen diffuses from the water into the bubble). Eventually, pO2(b) rises again, oxygen diffuses out into...

Physiological Attributes of Freshwater Marine and Terrestrial Animals

When we apply a physiological criterion to the problem of water balance, we find, surprisingly, that the physical world is divided not into just two environments, aquatic and terrestrial, but three freshwater aquatic, marine or saltwater aquatic, and terrestrial. Each has associated with it a particular suite of physical challenges and physiological adaptations, which can mark an animal as belonging in one of those habitat types (Box 7A). To illustrate, let us take a by now familiar example...

Info

T T w,p ' T w,o T s,m Ly *A A J T T w,p ' T w,o T s,m Ly *A A J Equation 7.11 lets us do some simple calculations about the consequences of living in soils with various water contents, and I have tabulated some of these in Table 7.2. It is a very complicated table, but its contents are important, so please bear with me as I go through it with you. At the heart of the table is an imposed variation of soil matric potential, listed in the leftmost column, each entry being double the one above it....

Atp

Figure 2.5 The overall scheme of calcite deposition in a calciloblast cell of a hermatypic coral. Ca + CO32- + H+ H+ + HCO3- H2CO3 H2O + CO2 used to power the separation of more hydrogen ions across the calciloblast membrane, which keeps calcite deposition going, which keeps photosynthesis going, and so on and so on. Physiology, the Organism, and the not-Organism Let us now step back a bit and reflect. I asserted earlier that physiology is essentially how animals use energy to do...

C

Chemical kinetics describes chemical reactions and the energetic forces that drive them. Central to this field of science is the idea of equilibrium between the reactants and products of a chemical reaction. Consider a hypothetical reaction in which reactants A and B react to form C and D. By convention, we write a chemical equation to represent the reaction where the coefficients j, k, l, m refer to the molar quantities of reactants A and B and products C and D, respectively. In any chemical...

The Organisms Fuzzy Boundary

The building of structures by animals is widespread, ubiquitous even. Sometimes these structures are humble simple tunnels in the ground or small piles of rubble. Sometimes they are grand the nests built by some species of termites to house their colonies are, in their own way, magnificent, even sublime. Sometimes they are built unintentionally the tracks left by an animal passing over or through sand or mud, for example. Sometimes they are built with seeming intention, like the fog catchment...

Burrow Linings as Metabolic Rectifiers

Thus, the burrow is a bit like the transistor-based structure described in Fig. 3.5. By directing a little met abolic energy into building and operating the burrow namely, the cost of digging it and ventilating it the worm activates a much larger flow of energy down an external potential energy gradient. This is not all the burrow does, though it can also act as a rectifier (Fig. 3.5), a device that selectively impedes or allows a flux of matter one way but not the other. Lugworms, when they...

Osk

Acoustics has a language all its own. Following is a short primer describing some of the terms that will be useful in this chapter. Sound is a periodic oscillation of pressure about a mean that propagates through a medium in the form of a traveling wave. The medium can be fluid, like air or water, or it can be solid. The simplest type of sound manifests itself as a sinusoidal oscillation of pressure (Fig 10A.1), p (Pa), with respect to time, t (s), described by the equation This equation is a...

Dgf

PN2(s) ApO2 pO2(PI-1) pO2(s) ApN pN PI-1) Figure 8.3 Variation of oxygen partial pressure and radius in a bubble held at a depth. a Partial pressures inside the bubble are equal to partial pressures in solution that has been elevated by a pressure increment, PI, determined by both hydrostatic pressure and surface tension at the bubble. b Oxygen partial pressures, pO2, in the bubble (subscript b) and in solution (subscript s) with respect to time, under a hypothetical regime of hydrostatic...

Htv

Challenges and Opportunities of the Terrestrial Environment Life originated in water, and for the most part it has stayed there. Beginning about 700 million years ago, however, living things began to move out of the water and onto land. The migration started with algae and other primitive plants, like mosses, but more complicated organisms, including animals, began moving onto land not long after, about 500 million years ago. Like birth, the move onto land puts organisms into a radically...

Steep concentration gradient

Figure 5.10 The distinction between concentration difference and concentration gradient. a The standard model of diffusion involves a flux, J, of a substance across a barrier of thickness xand cross-sectional area A between two compartments, I and II. b Concentration gradient, (C - Cjj) x, can be altered independently of the concentration difference simply by changing the boundary's thickness.

V

Figure 4.4 Schematic side view of three bioconvection plumes. The dark zones contain concentrated streams of microorganisms flowing downward in the culture medium. Figure 4.4 Schematic side view of three bioconvection plumes. The dark zones contain concentrated streams of microorganisms flowing downward in the culture medium. plicated form, drives the pattern of winds in thunderclouds. We ought to pause, now, and consider the facts carefully. Convection cells in rooms and storm clouds are...

Jhx

Why Must Insects and Spiders Breathe Air Among most animals, gas exchange systems are constructed to bring together two convective flows air and blood in the case of the lung at a diffusion exchange surface that is very thin. In the human lung, for example, about a micrometer separates the alveolar air from the blood, and the surface area of the entire exchange surface in the lungs is about 80 m2. This design is known as a coupled convection-diffusion exchanger. The coupling of convection and...

Bees Fanning Outward Pushme-pullyu

Termite Nest Section

Figure 11.7 Properties of air at the hive entrance during pushmi-pullyu ventilation of a honeybee hive. Periods of high oxygen concentration, low carbon dioxide concentration, and low temperature coincide with periods of no fanning and the movement of fresh air into the hive. Periods of low oxygen concentration, high carbon dioxide concentration, and high temperature coincide with fanning periods and the movement of spent air out of the hive. After Southwick and Moritz (1987) ning. A bee at the...

Architecture and Physiology in Sponges and Corals

The time has now come to see whether I have successfully bridged the gap between bioconvection and the solid structures of corals and sponges. To reprise the problem, I asserted in Chapter 4 that bioconvection cells represent a primitive type of structure, one that arises spontaneously from the interaction of a metabolic energy stream with a large-scale environmental gradient in potential energy. I suggested this model might be an organizing principle that would carry over to other, more...

Nephridiopore

Filtration occurs in one step, when the filtrate is formed from blood at high pressure in the glomerulus Fig. 2.2 . Filtration in earthworms, in contrast, is a two-step process. First, coelomic fluid is produced by filtration directly from the blood, analogously to the deposition of filtrate in the glomerulus. Then coelomic fluid is filtered across the nephridiostome into the tubule. Both filtration steps are pressure driven.2 The first step is driven by the worm's blood pressure. The annelid...

Adp

Figure 2.3 The transformations of energy in the production of filtrate. Energy in ATP is converted by the heart to blood pressure. The difference in pressure between blood vessels and the tubules of the nephron does the work of filtering the fluids of the body. tion takes is the deposition of minerals to build structures, coral reefs being the most spectacular. I will have much more to say about corals in Chapter 5. A coral reef consists of two parts, one living and the other not. The living...

Basal Metabolic Rate Fourier

Thermal Energy Balance in Vertebrate Thermoregulation The metabolic response to cold described in the text is a limited subset of the manipulations of heat flow that mammals and birds actually engage in. The complete suite of responses involves a complicated mix of variations of heat production by metabolism, adjustments of the body's thermal conductance, and heat dissipation by evaporation. The foundation of these responses is the relationship between thermodynamic heat flux and environmental...

Choanocytes

Figure 5.3 The components of sponges. a Connective elements. Spicules are mineralized connective elements made either of calcite or silica. Certain sponges lack spicules but are held together by networks of a fibrous protein, spongin. From Storeretal. 1979 b Cell types. c The choanocyte filters microorganisms and other food items from the stream of water driven through its collar by the flagellum. Solid arrows on collar of choanocyte indicate direction of movement of captured items of food b...

N nitrogen

Figure 6.9 The nitrogen rectifier in the burrow lining of a lugworm. lining acts as a nitrogen rectifier it allows nitrogen to escape easily in its positively charged form, ammonium, but it impedes backflow in its negatively charged form, nitrite. The retention of nitrogen outside the burrow has other beneficial consequences. The accumulating nitrite is a feedstock for nitrite-oxidizing bacteria, which produce nitrate as an end product. This nitrate can then serve as an electron acceptor for...

Chlamydomonas Nivalis Pattern

Transillumination Storm Clouds

Figure 3.5 a Structures can be made to do adaptive work by rectifying the flow of energy across the structure, symbolized by the diode. b More sophisticated adaptive work can result if the structure can adaptively control energy flow as if through a transistor. c Structures can store environmental energy in a capacitor, Cstr. Figure 3.5 a Structures can be made to do adaptive work by rectifying the flow of energy across the structure, symbolized by the diode. b More sophisticated adaptive work...

The Rare Earthworm

Earthworms are annelid, or segmented, worms that have ventured onto land. Earthworms are so familiar to us that it is surprising to learn what a rare thing a terrestrial annelid is. Of the 15,000 or so species in the phylum Annelida, about 10,000 are polychaete worms inhabiting marine environments, like the lugworms discussed in Chapter 5. Another 4,000 or so are polychaete and oligochaete worms and leeches inhabiting fresh water. Less than a thousand species of oligo-chaetes the earthworms and...

What Is Plastron In Insect Eggs

Insect Plastron Hydrofuge

Figure 8.6 Plastron gills in insects. a A sheet of air is held in place by a mat of hydrofuge hairs shown in cross-section as filled circles , which span a space between the insect's body dark shading and the water light shading . b Detail of a plastron gill of a blowfly egg. From Hinton 1963 Figure 8.6 Plastron gills in insects. a A sheet of air is held in place by a mat of hydrofuge hairs shown in cross-section as filled circles , which span a space between the insect's body dark shading and...

Redox Potential Gradients in Marine Sediments

Polychaeta Burrow

When the first burrowing animals broke through the metabolic Great Wall into the anaerobic world that had long been hidden beneath it, they inadvertently tapped into one of the Earth's most potent sources of energy. Spanning the oxygen-depleted zone is a redox potential difference of about a volt. Any burrowing animal that could exploit this redox potential would be on easy street. In a sediment, the redox potential has a different connotation than it does in a half-reaction. Sediments...

Readings

Biology's Phoenix Historical perspectives on the importance of the organism. American Zoologist 29 1067-1074. Bowler, P. J. 1992 . The Norton History of the Environmental Sciences. New York Norton amp Company. Collias, N. E., andE. C. Collias, eds. 1976 . External Construction by Animals. Benchmark Papers in Animal Behavior. Stroudsburg, PA Dowden, Hutchinson amp Ross. Donovan, S. K., ed. 1994 . The Paleobiology of Trace Fossils. Baltimore, MD Johns Hopkins University...

Where Physiology Comes From

I have just described the apparently spontaneous production of large-scale patterns of fluid flow in a culture of swimming microorganisms. The process is not spontaneous, however work is still being done on the system, just as it is in a room with baseboard heaters. It is a b C Figure 4.8 The progressive development of an anti-bubble of dense microorganisms in a cul-0 ture medium. a A local grouping of cells, delimit g ited by the dotted circle, may develop through -------------- random...

Baffling Cricket Harp

Tunel Gryllus Campestris

Frequency falls below a critical value known as the cutoff frequency, f . The cutoff frequency depends upon the flare of the horn, which is described by the equation Ax and A0 are the cross-sectional areas of the horn at distance x from the throat and at the throat, respectively, and fi is a constant known as the flaring constant. The cutoff frequency, f , is estimated reasonably well by the equation To transmit low frequencies well, therefore, the horn should have a small flaring constant. A...

The Earthworms Kidney

What about the earthworm's kidneys do they reflect the workings of an aquatic or a terrestrial animal centratedurine having about the same concentration as blood . The mammals and birds have taken kidney design a step further and are able to combine both high filtration rates and high degrees of water conservation they produce urine that is more concentrated than the blood. When we apply physiological criteria to deciding what the proper habitat of an earthworm might be, it is hard to escape...

Breathing Air Underwater

For insects and spiders, reliance on diffusion for gas distribution has imposed a stringent limitation it commits them irrevocably to breathing air. Should the tracheoles become flooded with water, for example, the insect could no longer enjoy the very high rates of diffusion that prevail in air. Consequently, insects and spiders that have returned to water have had to cobble together devices and structures that enable them to continue breathing air. Despite being committed to breathing air,...

The Lugworm Feedlot

A lugworm and its burrow therefore mobilize the energy that exists in the redox potential gradient in un disturbed mud. This is accomplished partly by the straightforward introduction of oxidants into sediments below the RPD layer, where they are not normally present. The worm also biases the movements of material across the burrow lining, thereby altering the mix of oxidants and nutrients in the sediment around the burrow. The overall result is a stimulation of growth in the sediments that has...

Express 4714 In Scientific Notation

Scientific Notation and Units of Measure The numbers in this book in scientific writing of all sorts, really may look odd to readers unfamiliar with mathematics, but in fact the notation is straightforward and the abbreviations fairly easy to learn. Scientific notation is simply a convenient way of writing very large or very small numbers. It expresses numbers as a multiple of a conveniently written number and a power of ten. For example, we could write 230 as the product of 2.3 x 100. However,...

Deborah Goemans

Epigraph to Chapter3 From Jack Handey, Deep Thoughts London Warner Books, 1996 . Figure4.1 From R. R. Kudo, Protozoology, 5th ed. 1966 courtesy of Charles C. Thomas, Publisher, Ltd., Springfield, Illinois. Figure 5.1 From Sidney Harris, What's So Funny about Science Los Altos, CA William Kaufmann, 1977 reprinted courtesy of Sidney Harris. Figures 5.3a and 5.4 From T. I. Storer, R. L. Usinger, R. C. Stebbins, and J. W. Nybakken, General Zoology, 6th ed. New York McGraw-Hill, 1979 courtesy of...

Modular Growth and Fractal Geometry

Fractal Geometry White Coral

Sponges and corals experience a type of growth, modular growth, that is more similar to the growth pattern of trees than that of animals. Modular growth, as the name implies, is the successive addition of identical or similar modular units to an existing organism. The structure these organisms take on as they grow is determined mainly by how fast and where new modules can be added. The process is easiest to illustrate with corals Fig. 5.5 . Each polyp secretes beneath it a layer of calcite,...