Sand dollar

Phylum Echinodermata Sea lilies, seastars, sea urchins, sand dollars, sea cucumbers... 

Sand dollar, Dendraster excentricus, sperm 28 Fertilization success reduced 50% in 60 min 2... 

Environment Canada (1992). Biological test method Fertilization assay using echinoids (sea urchins and sand dollars), amended November 1997. EPS l/RM/27. North Vancouver, BC. 

Sand dollar, Dendraster 28 excentricus, sperm Echinoderms, 3 species, 60-200 embryos... 

Diatom, Schroederella schroederi Diatom, Skeletonema costatum Dinoflagellate, Glenodinium halli Purple sea urchin, Strongylocentrotus purpuratus, embryos Sand dollar, Dendraster excentricus Atlantic herring, Clupea harengus, embryos Mud crab, Rithropanopeus harrissii, larvae Diet... 

A 77-kDa WD repeat protein, called EMAP, from sea urchins reduces the frequency of rescues by eightfold without producing a change in the frequency of catastrophe (Hamill et al, 1998). The mechanism for this activity is still to be investigated. EMAP-like proteins have also been identified in starfish, sand dollars, and mammals. 

Gray, I.E., McCloskey, L.R., and Weihe, S.C., The commensal crab Dissodactylus mellitae and its reaction to sand dollar host factor, J. Elisha Mitchell Soc., 84, 472, 1968. 

A variety of other amino acid- or peptide-based cues also induce larval settlement and metamorphosis. For example, larvae of the sand dollar Dendraster excentricus settle and metamorphose in response to (1) a peptide-based cue from sand associated with adults, and (2) to water conditioned by adults.135 137 The nudibranch Adalaria proxima is induced to settle and metamorphose by a water-soluble-peptide-based cue from its bryozoan host Electra pilosa.138 139 A surface-associated peptide inducer has been proposed for the tube worm Phragmatopoma lapidosa californica140 but its role as a natural inducer remains to be defined. 

Highsmith, R.C., Induced settlement and metamorphosis of sand dollar Dendraster excentricus) larvae in predator-free sites adult sand dollar beds, Ecology, 63, 329, 1982. 

Burke, R.D., Phermonal control of metamorphosis in the pacific sand dollar, Dendraster excentricus, Science, 225, 440, 1984. 

Sand dollars, Dendraster excentricus, exhibit gregarious settlement, and larvae undergo settlement and metamorphosis in the presence of adult-associated sand.92 Adults produce a chemical cue that remains associated with the sand and is stable for at least 7 weeks. Thus, settlement occurs within or near existing sand dollar beds. Highsmith92 suggested that the cue was a small peptide. This was confirmed by Burke,20-21 who isolated an active peptide of 980 Da from extracts of sands from sand dollar beds. 

In some cases, the nature of the chemical signal is known as well. Larvae of the tube worm Phragmatopoma californica undergo metamorphosis in response to a proteinaceous substance present in the tubes built by conspecific adults.95 Larvae of the sand dollar Dendraster excentricus... 

The minerals calcite and aragonite are polymorphs of calcium carbonate. Calcite is the more stable of the two, and aragonite is most often seen in objects made of speleothems, the rocks formed in solution caverns. Aragonite is also an important constituent in many materials of organic origin, such as mollusk shells and the outer skeletons of sand dollars and coral. Calcite is the major component of the rocks limestone and marble, and as such is found in collections as sculpture, building stone, in mosaics, and in inlay or in tarsia. 

Echinodermata Starfish, urchins, crinoids, sand dollars, sea cucumbers Spiny-skinned, pentaradial (five-part) symmetry marine, most are sedentary or sessile... 

Mabuchi I, Hamaguchi Y, Fujimoto H etal. (1993) A rho-like protein is involved in the organization of the contractile ring in dividing sand dollar eggs. Zygotes 1 325-331. 

Some animals are radially symmetrical. Shaped like either short or long cylinders, these stationary or slow-moving organisms have distinct top and bottom surfaces but lack fronts and backs, heads or tails. A plane could pass through a radially symmetrical animal in several places to create two identical halves. Starfish, jellyfish, sea cucumbers, sea lilies, and sand dollars are a few examples of radially symmetrical animals. 

Starfish (sea stars), sea cucumbers, brittle stars, sand dollars, and sea urchins are members of a group of spiny-skinned animals known as echinoderms. All echinoderms are radially symmetrical, and most have five or more arms extending from a central disk, as shown in Figure 4.5. Their bodies are supported by internal skeletons which are solid in some species and jointed in others. Most echinoderms are designed so that their mouths are located on the ventral sides and their anuses on the dorsal surface. Depending on the species, the nutritional strategies of echinoderms vary from carnivores to detritivores or herbivores. 

Sand dollars are so flat that at first look they do not resemble their echinoderm relatives. The plates of their skeletons are fused and fixed, and the external surfaces are covered with tiny spines that look like fuzz or a short coat of hair. Sand dollars use their spines to burrow into sand. Once buried, the spines collect small food particles that fall among the spines and transfer them to the mouth. As shown in the upper color insert on page C-7, the common sand dollar (Echinarachnius parma) may be brown with purple or red tints. A five-petal pattern on the sand dollar s dorsal side corresponds to the five legs of a starfish. Holes near the tips of the petals allow the animal to extend tube feet, which are used for respiration. Most specimens measure about 3 inches (7.5 cm) in width. 

Environment Canada. 1992. Biological Test Method Fertilization Assay Using Echinoids (Sea Urchins and Sand Dollars). Environment Canada, Environmental Protection, Conservation and Protection. Environmental Protection Series Report EPS 1 /RM/27, Ottawa, Canada. 

Sand Dollar Condominium Resort - is great for families, the largest rooms on Bonaire. 

Findings from micromanipulation experiments have shown that different cells rely on either the spindle or the asters to determine the cleavage plane (Figure 20-41). For instance, the presence of two asters determines where cleavage occurs in fertilized sand dollar eggs, whereas the spindle determines the cleavage plane in animal cells. 

Sand dollar, Dendraster excentricus, 880 Sea cucumber, Stichopus spp., 27,872 Sea urchin... 

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