nephridiopore 1
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...
Info Smv
Figure 12.3 Hypothetical patterns of ocean circulation and heat transport during a an interglacial period and a an ice age. This schematic view represents a cross-section from the South Pole S to the North N , cutting through a temperate southern region TS , the Equator E , and a temperate northern region TN . Figure 12.3 Hypothetical patterns of ocean circulation and heat transport during a an interglacial period and a an ice age. This schematic view represents a cross-section from the South...
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...
Info Vld
Figure 5A.3 Wood-Jones model for laminar growth of corals. The coral Acropora hyacinthus forms a flat, circular plate in the mature form. It grows by lateral addition of material to the plate, which eventually closes in on itself and forms a circular platform. After Dauget 1991 nation of growth and reproduction between polyps is not necessary. The last model is known to botanists as Aubreville's model, but coral biologists prefer to call it the Wood-Jones model. The three models discussed so...
Info Xua
Figure 12.6 Negative feedback, stability and instability. a Gain and phase of the transfer functions are matched properly deviations from the desired value are small. b Gain of the transfer function is too high driver over-corrects for deviations the system goes into an unstable oscillation. c Phase response of the transfer function is too slow driver's reaction time is delayed the system also is unstable. Figure 12.7 A simple symbiosis consisting of a heterotroph H , photoautotroph P , and a...
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
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...
t 1
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
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
Benson, K. R. 1989 . 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...
Info Rti
Figure 10.4 Vibration and sound emission at a vibrating reed standing alone. a Air blowing past the edge of a reed generates turbulent eddies that set the reed into vibration. b The chaotic variation of sound pressure resulting from secondary components of the reed's vibration. c The power spectrum of an undamped vibrating reed. quency, but the buzziness shows up as a smearing of the energy at frequencies on either side of the resonant frequency. The sound energy coming out of the reed is...
Info Kug
- 1971 . Plastron respiration in the mite Platyseius italicus. Journal of Insect Physiology 17 1185-1199. Hoffman, G. D., and P. B. McEvoy 1985 . Mechanical limitations on feeding by meadow spittlebugs Philaenus spumarius Homoptera Cercopidae on wild and cultivated host plants. Ecological Entomology 10 415-426. Horsfield, D. 1977 . Relationships between feeding of Philaenus spumarius L. and the amino acid concentration in the xylem sap. Ecological Entomology 2 259-266. - 1978 . Evidence for...
Baffling Cricket Harp
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...
Info Gbe
interglacial climate we now enjoy. Obviously, the record is rather noisy, but look in particular at the period between 20,000 and 35,000 years before the present b.p. . During this time, the climate seems to switch periodically between a warm phase and a cool phase roughly seven or eight degrees cooler. This switching also occurs during the climb out of the ice age, beginning around 17,000 years b.p. The warming trend is clear, but twice, during the Older and Younger Dryas periods, the Earth...
Modular Growth and Fractal Geometry
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,...