Functional and Evolutionary Ecology of Fleas: A Model for

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Some species brood their embryos on the body surface. At the end of a recovery stroke, the podium extends in the direction of movement and attaches to the substratum. An array of "whiskers" and fin spines make catfish immediately recognizable, from the huge Flathead and prevalent Bullheads, to the tiny Madtoms. Nemertean Phylogeny The fossil record is of no use in establishing the origin of nemerteans in geological time. Insect Biology: A Textbook of Entomology. Ocelli: A celestial compass in the desert ant Cataglyphis.

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Respiration in the Invertebrates (Macmillan studies in

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University of California Press, Berkeley, pp. 181–188. Senior Division Only: includes projects described within the category Microbiology (Medical). There may also be active uptake of water and salts from food across the gut wall. A mucous bag, produced by se- cretions from segment 12, is held as shown in Figure 13.16C, so that water flows into the open end of the bag and through its mucous wall. Beneath the dermis are well developed lay- ers of circular and longitudinal muscles.

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Protocols in Protozoology

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THE PROTISTS 127UNCORRECTED PAGE PROOFS Figure 5.3 (A–D) Activity in a generalized protist food vacuole. (A) Intact food mass within food vacuole. (B) The vacuolar membrane and edge of the food mass (magnified view). (C) Formation of microvilli and vesicles of vac- uolar membrane. (D) Uptake of vesicles containing products of digestion into the cytoplasm. (E) Cross section through the cytostome of the ciliate Helicoprorodon, showing the area of food vacuole formation at center.

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Crustaceans: Physiological Characteristics, Evolution and

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This best-selling introduction to the biology of invertebrates through a survey by groups emphasizes adaptive morphology and physiology while covering anatomical ground plans and basic developmental patterns. Hemoglobin has been detected in one species of Neodasys, and at least some gastrotrichs are capable of anaerobic respiration. This is the principle be- hind the fact that the largest protists (other than certain colonies) assume shapes that are elongate, thin, or flat- tened—shapes that maintain small diffusion distances.

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Insects and Ecosystem Function (Ecological Studies)

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Gametes are released into the 26 CHAPTER TWENTY-ONE Figure 21.21 (A) An articulate brachiopod (ventral side up; cutaway view). A good example of a grade is the large group of gastropod taxa that have achieved shellessness. The coelomic spaces in leeches are red- uced and continuous, so these animals cannot move like a truly segmented worm. Fossil evidence of sponges dates to the Precambrian, 580 million years ago (Li et al. 1998).

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Siphonophores and Velellids (No. 29)

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However, as in cnidarians, no true ganglia occur, a condition that contrasts markedly with the presence of a centralized nervous system in bilateral Metazoa. Others attach the co- coons to their own bodies and brood them externally. Div: “Arrow” Dynamics; Measuring the Effect of Aerodynamic Design on Vehicular Drag. We do not yet have enough details to fill in the evolu- tionary history of this new tree or generate a well- corroborated cladogram, but Figure 15.36 provides a simple (hypothetical) model of the current thinking.

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Prospects of Organic Waste Management and the Significance

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Gut ultrastructure and digestive physiology of two marine nematodes, Chromadorina germanica (Butschli, 1874) and Diplolaimella sp. The tegumental channels near the body surface may facilitate pinocytosis of nutri- ents from the host. Effect of Age on Aerobic Abilities; Peripheral Vision; Correlation of Strength with Gender; Effect of Vaccination on Antibody Development in Neonatal Bovines; Lung Capacity, Age, and Exercise; Crossed Hand-Eye Dominance.

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Titan The Life of John D. Rockefeller Sr.

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Amebocytes in the coenenchyme secrete a flexible or stiff internal axial rod as a supportive base embedded in the coenenchymal mass. The embryos develop di- 350 CHAPTER TWELVE UNCORRECTED PAGE PROOFS Figure 12.13 The trunk muscles of a kinorhynch (lateral view). rectly to juveniles, which emerge from the egg cases with 11 of the 13 body segments already formed (Koz- loff 1972). Of experiments Baptist missionaries by this living faith a crude and.

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Reproductive Biology of Invertebrates

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The theory of nat- ural selection implies that, given a complete under- standing of the environment and genetics, evolutionary outcomes should be largely predictable. The order includes several living species (from Namibia, South Africa, and Tanzania) and one fossil species (from Baltic amber). And, of course, their innards are cellular, not syncytial. A. suum like P. equorum contains a large irregular nucleus lying in a central cytoplasmic mass which branches into many amoeboid extensions [ 10, 20, 47 – 49 ].

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The American Horseshoe Crab

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Other suggestions have included auditory, gas exchange, excretory, and tactile activities. With (often multicellular) protonephridia associat- ed with the gonads as a urogenital system 7. Systematists use a great variety of tools to study the relationships among taxa. How do these characteristics classify animals? Animal evolution: the end of intermediate taxa? In the group Priapulida, the mesenteries that suspend organs are reported to be formed from extracellular material produced by coelomocytes or amoebocytes that move freely in the body cavity.

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