Trends in Acarology: Proceedings of the 12th International

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However, the origin of the Pa- narthropoda itself is highly controversial. Most tuni- cates are hermaphroditic, with relatively simple reproductive systems. This course provides students with the opportunity to investigate living and fossil invertebrates in the northern and participate in a field research project using invertebrates as study organisms. ), (3) I coordinate two sections of BIO 475L (Parasitology Laboratory), and (4) lecture for four weeks on nonparametric statistics in BIO 682 (Quantitative Biology).

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Insect Spiracular System (Ellis Horwood series in entomology

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With protonephridia, but without special circulato- ry or gas exchange structures 9. Musculature formed largely of myoepithelial cells (= epitheliomuscular cells), derived from ectoderm and entoderm (adult epidermis and gastrodermis) 5. In some species purely parthenogenetic populations apparently exist only in some localities. In none, howev- PHYLUM CNIDARIA 255UNCORRECTED PAGE PROOFS 256 CHAPTER EIGHT Figure 8.37 Some hydrozoan life cycles. (A) Life cycle of Hydra. It is known as bird-eater because, like other large spiders, it will sometimes prey on small birds as well as small mammals and lizards.

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Revision of North American Bees of the Subgenus

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Green hydra are small, seldom more than 0.4 inches (10 mm) long, with tentacles about half the length of the column. Body Wall The body wall of nemerteans comprises an epidermis, a dermis, relatively thick muscle layers surrounding the gut and other internal organs, and a mesenchyme of varying thickness (Figure 11.2). Handbook of the Marine Fauna of North-West Europe. Tantulocarida, a new class of Crustacea ectoparasitic on other crustaceans.

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Phylogeny and Evolution of the Mollusca

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The water is passed into the main vesicle, which is collapsed by the action of contractile fibrils, thereby expelling the water through a discharge channel to the outside. It is likely that the protoneph- ridia also remove nitrogenous excretory products from the body. Phylum Gastrotricha: The Gastrotrichs The phylum Gastrotricha (Greek gasteros, “stomach”; tri- chos, “hair”) comprises about 450 species of small ma- rine, brackish, and freshwater Metazoa.

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Worm (Little Nippers: Creepy Creatures)

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A pharynx sucks in the organic debris which the muscular gizzard grinds. As the pilidium swims and feeds, a series of invagina- tions in the larval ectoderm (Figure 11.15B) eventually pinch off internally to produce the presumptive adult ec- toderm. Use 40X and 100X to study the wholemount of an adult hydra with a testis (Fig 1). Members of this phylum are ubiquitous in all aquatic habitats from the poles to the equator. In some areas of the world’s seas, ctenophores may be the dominant macrozooplankters and planktonic predators (e.g., Mertensia ovum in the Arctic region). 276 CHAPTER NINE Figure 9.4 Stereogram of the arrangement of muscle fibers in Pleurobrachia, a cydippid ctenophore.

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Sea Stingers and Other Venomous and Poisonous Marine

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The first is via diffusible signaling mol- ecules released from one cell and detected by the adja- cent cell. The epidermis is partly cellu- lar and partly syncytial and is ciliated ventrally (thus the derivation of the phylum name: “hairy belly”). Here they stay until they are old enough to make periodic excursions away from their parent and eventually assume an independent life. They do not have effective ways to support a big physique or the muscles needed to power a large body. The median eye generally first appears during the nauplius larval stage, and for that reason it is often called a naupliar eye.

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An Identification Guide to the Larval Marine Invertebrates

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The class Arachnida containing spiders, scorpions, mites, and ticks are also chelicerates that lack antenna, have chelicera (fangs) and 4 pairs of legs, but they live in terrestrial habitats and breathe through book lungs or trachea. Print out what pieces you will use and divide them up, so you know how many you need to get done each day. The details of suspension feeding have been examined in some acorn worms (e.g. The Mantophasmatodea is the most recently de- scribed order of insects (Klass et al. 2002) and the first new insect order described since 1914.

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Ant Ecology

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In the latter case fertilization takes place in the ovary. Nomenclatorial stabilization of the Nearctic fauna, with a revised synonymic check list. The mouthparts, instead of being adapted for handling and chewing solid pieces of food, are elongated into a needle-like beak. In all cases, excavation begins quickly after larval settlement. In octopuses, many color changes are accompanied by modifications in the surface texture of the body, mediated by muscles be- neath the skin—something like elaborate, controlled “gooseflesh.” In addition to the color patterns formed by chro- matophores, some cephalopods are bioluminescent.

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Pictorial Atlas of Australasian Culicoides Wings: Diptera:

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The basic body plan described above can be manifest as a swimming medusa or attached polyp. Download link will be sent to your email address instantly after payment has been processed - please check your Spam Folder for your "Download Products Notice" email. In some aplacophorans, the teeth form simple plates embedded in either side of the lateral foregut wall, while in others they form a transverse row, or up to 50 rows, with as many as 24 teeth per row.

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Physiological Approach to the Lower Animals

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Ophiuroids possess ten invaginations of the body wall called bursae, which open to the outside through ciliated slits (Figure 22.9A,C). A simple example is hair color in humans; black, brown, red, and blond are all states of the character “hair color.” Not only can charac- ters vary within a species, but they also typically have several states among groups of species within higher taxa, such as patterns of body hair among various pri- mates or the spine patterns on the legs of crustaceans.

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