Sex and Death in Protozoa: The History of Obsession

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A record 28-foot (8.5 m) octopus and 60-foot (18 m) squid make these the largest of all the invertebrates. The bonding agent is typically produced from polyphenols and catalyzed by polyphe- nol oxidases present in the protein layers of the cuticle. In stomatopods and aquatic isopods a current is generated by the beating of the pleopods. Gastropod shells are extremely diverse in size and shape (Figure 20.1C–F). Like the prosome of lophophor- ates, the pterobranch prosome is reduced to a small plate, called the preoral disc or cephalic shield, which generally folds ventrally over the mouth.

The World of Ants : A Science-Fiction Universe

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Phylum Platyhelminthes Identification of these animals requires microscopic examination of the repro- ductive system from thin slices (sections) prepared according to procedures some- what reminiscent of alchemy. The roughly 7-10,000 living species of Echinoderms have a diverse arrangement of body plans including: sea stars (Asteroids), brittle stars (Ophiuroids), sea urchins (Echinoids), feather stars (Crinoids) and the group to which medusa worms belong: the sea cucumbers (Holothuroids).

Textbook of Zoology Invertebrates

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Movable spines and pedicellariae contain muscles and other tissues that lie outside the main skeletal framework of the body wall (Figure 22.4H–J). The black number tells you the population of whatever it is. You have two weeks to complete a lapbook. The ex- treme reduction of the abdomen in this group allows for very rapid movement because adjacent limbs can move in directions that avoid interference with one another. 42 CHAPTER SIXTEENUNCORRECTED PAGE PROOFS TABLE 16.1 Comparison of distinguishing features among the five crustacean classes Body tagmata and number of Carapace or segments in each Taxon cephalic shield (excluding telson) Thoracopods Maxillipeds Class Remipedia Cephalic shield Cephalon (5) Not phyllopodous 1 pair Trunk (up to 32) Class Cephalocarida Cephalic shield Cephalon (5) Phyllopodous None Thorax (8) Abdomen (11) Class Branchiopoda, Cephalic shield Cephalon (5) Phyllopodous None Order Anostraca Thorax (usually 11) Abdomen usually 8) Class Branchiopoda, Carapace Cephalon (5) Phyllopodous None Order Notostraca Thorax (11) Abdomen (many segments) Class Branchiopoda, Carapace (bivalved, Cephalon (5) Phyllopodous None Order Diplostraca hinged or folded) Trunk (10–32, or obscured) Class Malacostraca, Large, “folded” Cephalon (5) Phyllopodous None Subclass Phyllocarida carapace covers Thorax (8) thorax Abdomen (7) Class Malacostraca, Carapace well Cephalon (5) Not phyllopodous; 0 to 3 pairs Subclass developed or Thorax (8) uniramous in many Eumalacostraca secondarily Abdomen (6) reduced or lost Class Maxillopoda Carapace Cephalon (5) Not phyllopodous; 0 or 1 pair or cephalic shield Thorax (6) often reduced Abdomen (4) Brachyuran crab legs are hinged in such a way that most of their motion involves lateral extension (abduc- tion) and medial flexion (adduction) rather than rota- tion frontward and backward.

Monograph of Living Chitons (Mollusca: Polyplacophora),

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ORDER OPHIURIDA: Bursae present; dorsal and ventral arm shields present and usually well devel- oped; unbranched arms incapable of coiling verti- cally; madreporite on oral surface; digestive glands wholly within central disc. Dioecious; males commonly with “hooked” poste- rior end 10. Origin of the insect wing and wing articula- tion from the insect leg. In beetles, the posterior wings function in flight, while the anterior wings act as covers that protect the flight wings when the beetle is on the ground or burrowing.

Cyst Forming Nematodes of India

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Cyclo- morphosis is coupled with gonadal development, and in H. crispae only the summer morph is sexually mature. In those species with an external test, the shell itself may divide more or less equally in conjunction with the formation of daughter cells (e.g., Pamphagus); or, as occurs more frequently, the shell may be retained by one daughter cell, the other producing a new shell (e.g., Arcella). Spiracles line the sides of the insect's abdomen and open into their breathing tubes or trachea.

Bee Conservation: Evidence for the effects of interventions

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Furthermore, the animal must maintain an appropriate distribution of legs at all times in various phases of power and recovery strokes so that its weight is fully supported. A vertical section has been partly cut away to show the structure between the inner and outer walls (i.e., vertical parieties and hori- zontal tabula). Commonly, the disease develops slowly, with intermit- tent diarrhea, cramps, vomiting, and general malaise.

Physiological Approach to the Lower Animals;

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In stramenopiles, the chloroplast is surrounded by four membranes and the thylakoids occur in stacks of three. When nephridia are present, they also drain into this system. PHYLUM CNIDARIA 267UNCORRECTED PAGE PROOFS Spaulding, J. Ha- waiians refer to the zoanthid Palythoa toxica as “limu- make-o-Hana” (“the sacred deadly seaweed of Hana”). Parallel evolution of nonfeeding larvae in echinoids. Biologists may present their ideas on such matters of relationship in the form of trees, classifications, or narrative discussions (evolutionary scenarios).

Crustacea Guide Of The World

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Over 800,000 insect specimens have been added over the last five years. The exiting water provides the locomotor force. When the cuticular projec- tions are touched, that movement is translated into a de- formation of the nerve ending, thereby initiating a nerve impulse. The wingless insects belong either to groups that have secondarily lost the wings (e.g., fleas, lice, certain scale insects) or to primitive taxa (the apterygotes) that arose prior to the evolution of wings.

Treatise on Zoology - Anatomy, Taxonomy, Biology. The

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A Synoptical Review of Life Histories of Digenetic Trematodes of Vertebrates. These collections provide the basis for understanding the ocean's biodiversity, the evolutionary history of life on Earth, and the rates and characteristics of climate change. A pair of circumenteric connectives emerges from the hind part of the cere- bral ganglion and extends posteroventrally to meet in a large ventral or subenteric ganglion located in the trunk epidermis (Figure 23.2G). The advent of camouflage and ink pro- duction, coupled with high mobility and complex behav- ior, played a major role in the success of these animals in their radical modification of the basic molluscan bauplan.

Gene Function: E. Coli and Its Heritable Elements

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The blood of many kinds of small arthropods is colorless, simply carrying gases in solution. Synapomorphies of the class Gastropoda: (36) torsion and its associated anatomical conditions; (37) further concen- tration of internal organs as visceral hump. UNCORRECTED PAGE PROOFS Some ctenophores prey upon larger animals, especial- ly gelatinous forms. Electron-dense plaques located on the inner surface of the nuclear envelope act as organizers for the mitotic spindle.