Category Archives: Invertebrates

Atlas of European Millipedes: Class Diplopoda: Orders

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If properly orchestrated, the male’s “tune” eventually at- tracts the female, and contact is made. Moore (ed.), Treatise on Invertebrate Paleontology, Pt. Tell the children that Linnaeus was a Christian and once proclaimed, "God created, Linnaeus ordered." The stomach leads to an elongate intestine or midgut, which is more or less straight but usually bears numerous lateral diverticula. Thus, the flatness of their bodies facilitates gas exchange across the body wall, between the tissues and the environment; nutrients are distributed internally by the digestive system and by diffusion, which is aided by general body movements.

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Almost periodic operators and related nonlinear integrable

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Many, if not most, species inject a poison into their prey when they attack. Crustacean fossils from Cambrian Lagerstätten deposits have eyes that strongly resemble modern crustacean eyes, at least superficially. Nevertheless, Maggenti [ 67 ] suggested an excretory function in Plectus spp. These ceca produce the en- zymes for final digestion and are the site of absorption of the digestive products. In species where little yolk is present, cleavage is holoblastic, and cell fates and germ layer formation have been traced accurately.

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Invertibrate Zoology

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As discussed in Chapter 3, dif- 414 CHAPTER THIRTEENUNCORRECTED PAGE PROOFS ferent pigments—even different forms of the same pig- ment—have different oxygen loading and unloading characteristics. Ventrally, in the trunk, the nerve ring connects with a sin- gle ventral nerve cord extending the length of the body. The ctenophores are radially (biradially) symmetrical, diploblastic (or perhaps triploblastic) animals, resembling cnidarians in several respects. There are many thousands of described species, yet the fauna of much of the tropical soils is still unknown.

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Invertebrates - Second Edition [Hardcover]

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Evidence from 18S ribosomal DNA that the lophophorates are protostome animals. Not responsible for typographical or illustrative errors. Many xeric insects also undergo periods of dormancy (i.e., diapause or aestivation) during some stage of the life cycle, characterized by a lowering of the basal meta- bolic rate and cessation of movement, which allow them to withstand prolonged periods of temperature and moisture extremes. The two pairs of heart atria, nephridia, and ctenidia in Nautilus (and two pairs of retractor mus- cles in some fossil forms) have also been regarded by some workers as primitive “metameric” features.

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Fauna Entomologica Scandinavica, the Hydrophiloidea

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In addition, leeches have from two to ten dorsal eyes of varying complexity, and special sensory papillae that bear bristles extending from the body sur- face. ORDER ANTIPATHARIA: Black or thorny corals. Histomonas melea- gridis is a cosmopolitan parasite of gallinaceous fowl. Jet propulsion and the evolution of cephalopods. Several polychaete larvae are shown in Figure 13.34. Product Science (Biological) (Junior Division Only): Comparison and testing of commercial off-the-shelf products for quality and/or effectiveness for intended use in real-world consumer-oriented applications.

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Agricultural Insect Pests of the Tropics and their Control

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In those species that are largely confined to moist habitats and nocturnal ac- tivity patterns, a significant portion of the excretory wastes may be ammonia rather than uric acid. During intranuclear mitosis, the spindle forms inside of the nucleus; during extranuclear mitosis, the spindle forms outside of the nucleus (see Raikov 1994 for more detailed descriptions of protist mitosis). 128 CHAPTER FIVEUNCORRECTED PAGE PROOFS Figure 5.4 Protist mito- chondria, showing variation in the inner membrane (i.e., cristae). (A) Lamellar cristae from the mitochondrion of the choanoflagellate Stephanocea (× 80,000). (B) Discoidal cristae from the mitochondrion of the euglenid Euglena spirogyra (× 40,000). (C) Tubular cristae from the mitochondri- on of the chlorophyte Pteromonas lacertae (× 27,000). (D) Dilated tubular cristae from the mitochondrion of Apuso- monas proboscidea, an enigmatic flagellate of uncertain affini- ty (× 97,000). (A) (B) (C) (D) Protist nuclei also show remarkable diversity.

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Nematodes as Biological Control Agents (Cabi)

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The swimming performance of the sea-anemone Boloceroides. Conocyema polymorpha lives in the nephridia of octopuses, and Microcyema gracile in cuttlefishes of the genus Sepia. The afferent vessel extends unbranched from the re- gion of the end bulb to the base of the lophophore. Mating has been studied in some gordioids. Each can act like a suction disk that is controlled by hydraulic and muscular action.

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Pine Wilt Disease: A Worldwide Threat to Forest Ecosystems

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Their mantles are not formed into elongate siphons; thus they cannot burrow deeply (see Figure 20.21A). Many of the fundamentally unicellular protist phyla also contain species that form colonies. In some species a new or “spare” house may be found be- neath the functional house; after escaping the clogged house, the “spare” is rapidly inflated. Members of the order Cestida are also compressed in the tentacular plane and extremely elongated in the sto- modeal plane, giving these ctenophores a striking snake- or ribbon-like appearance.

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C. elegans: A Practical Approach

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The suborder Hyperiidea includes exclusively pelag- ic amphipods that have apparently escaped the confines of benthic life by becoming associated with other plank- ters, particularly gelatinous zooplankton such as medusae, ctenophores, and salps. They release ammonia both through nephridia and by way of the gills. Those are the major characteristics of vertebrates. Microvillar eyespots are present on the pharyngeal nerve ring in at least some species.

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A General Zoology of the Invertebrates

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Settlement requirements of molluscan larvae: New data on chemical and genetic roles. Within this clade are two major groups: the oligochaetes and the hirudinoideans. Seashore Animals of the Southeast: A Guide to Common Shallow-water Invertebrates of the Southeastern Atlantic Coast. The genus Panthera can be broken down to include Panthera leo (lion) and Panthera tigris (tiger). Sam has had the opportunity to study and perform independent research in Ecuador and at Bamfield Marine Science Center in British Columbia.

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