Rotifera VIII: A Comparative Approach: Proceedings of the

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Only by designating additional ancestral features can we eliminate the trichotomy. It doesn’t have to be perfect.) At the top of each section write one of these words: producer, consumer, decomposer. Placozoa, Porifera, Cnidaria, and Ctenophora. The female housefly deposits her eggs in the crevices and corners of the same kinds of decaying organic matter adults feed on. PDF File: Reasoning With Geometry Answer Key .... Many fresh water and marine sponges disintegrate in adverse environmental conditions particularly in winter, leaving small rounded balls called reduction bodies.

Sea-Spiders (Pycnogonida) of the North-East Atlantic: Keys

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Gemmules are asexual reproductive bodies of most of the freshwater and a few marine sponges. Arrows indicate the animal’s direction of travel; dots are points of leg-tip contact with the substratum. (E) Locomotion in a scolopendrid centipede at various speeds. 1–4 show the body waves and leg actions at increasing speeds. In primitive bi- valves, the gonoducts join the nephridia and gametes are released through urogenital pores.

The Oxford Book of Invertebrates: Protozoa, Sponges,

Derek Whiteley

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There is evidence that some protists (e.g., rhizopodans, euglenids, ciliates) are independent lineages and are not related to any multicellular organ- isms. Earthworms have touch, light, vibration and chemical receptors all along the entire body surface. This phenomenon, PHYLUM CTENOPHORA: THE COMB JELLIES 277 Figure 9.6 Colloblasts. (A) The functional parts of a col- loblast. (B) Longitudinal section. (C) Colloblasts on the lat- eral tentacle filaments (tentillae) of Pleurobrachia (scanning electron micrograph). (D) Fired colloblasts of Pleuro- brachia, showing adhesive spherules attached to fragments of a copepod (small crustacean). (E) Fired colloblasts are still attached to the tentacle filament.

Spineless Wonders: Strange Tales from the Invertebrate World

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Carapace well developed, covering most of thorax, but never fused with more than four anterior thoracic segments; maxillipeds (1–2 pairs) not associated with cephalic appendages; thoracom- ere 1 separated from head by internal skeletal bar; abdomen with well developed tail fan; pereopods biramous, except last pair, which are sometimes re- duced; pleopods reduced or, in males, modified; com- pound eyes stalked, sometimes reduced; gills absent; usually with a statocyst in each uropodal endopod; adults with antennal glands (Figures 16.12A–B, 16.30B, 16.33C).

Insect Masquerades

Hilda Simon

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These amoebocytes produce fibers that suspend the digestive system and other organs in pseudocoelom. Saxipendium coronatum, new genus, new species (Hemichordata: Enteropneusta): The un- usual spaghetti worms of the Galapagos rift hydrothermal vents. Males of most species are winged, but some are wingless; females are always wingless. Asexual reproduction by transverse binary fission (homothetogenic) 7. Their skins will darken and harden as they enter the pupa stage.

Invertebrate Tissue Culture: Applications in Medicine,

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Those that are thought to have separate sexes may also be protandric, but with a long temporal separation of the male and female phases. To post to CRUST-L, send messages to CRUST-L@VIMS. Molluscs range in size from microscopic bivalves to giant clams (Tridacnidae) that reach 1 m in length, to giant squids (Architeuthis) reach- PHYLUM MOLLUSCA 15 (D) Figure 20.11 The anatomy of a squid (Loligo). (A) External morphology (anterior view). (B) External morphology (posterior view). (C) Internal anatomy of a male.

Biosynthesis in Insects: Advanced Edition

E David Morgan

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Protist cells responsible for the produc- tion of gametes are usually called gamonts. Although the preceding discussion may seem clear- cut, it is an oversimplification. However, the absence of a large body coelom in arthropods is a secondary condition resulting from a loss of the ancestral coelomic body cavity during the evolution of the arthropod bauplan, not a primary condition like that seen in the true blastocoelomates (see Chapter 12), at least some of which may never have had a true coelom in their ancestry.

Medical Entomology for Students

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Body Wall, Support, and Locomotion The nematode body is covered by a well developed and complexly layered cuticle secreted by the epidermis (Figure 12.16D). Bees appear to utilize a hierarchical series of flight orientation mechanisms; when the primary mechanism is blocked, a bee can switch to a secondary system. Except for their basic rhabdomeric nature, however, the structure of median eye units is un- like that of the ommatidia of true compound eyes.

Evolutionary Developmental Biology of Crustacea (Crustacean

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Die Abstammung der Anneliden und Chordaten und die Stellung der Ctenophoren und Platyhelminthen im System. Others have lecithotrophic veligers that remain plank- tonic only for short periods. The digestive system is a complete tube with mouth and anus. Gonads are low conical mounds on the surface of the column, ovaries are larger than testes. Experimental embryology of the Turbel- laria: Present knowledge, open questions, and future trends. Ancylostoma duodenale: The Common Hookworm; 37.

Spiders of the World

Rod Preston-Mafham

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Scr. 11: 77–81. [Dubious and difficult reading.] Sarvaas, A. Many of the evolutionary “milestones” and “first” fossils are given extremely different dates in different textbooks. The Mandibulata were united on the basis of the mandibles (which appear to be homologous in these taxa) and a similar head and head appendage structure.* It was not until the late 1980s that Snodgrass’s long- standing view of arthropod relationships began to be se- riously questioned. Certain epidermal glands secrete en- zymes that begin digesting the old endocuticle, thus separating the exoskeleton from the epidermis.