echinodermnoun. Any member of the Echinodermata, a group of radially symmetric, spiny-skinned marine animals. Examples of echinoderms include seastars, sea urchins, sea cucumbers, crinoids, and sand dollars. Etymology: ἐχῖνος + δέρμα
Q. What is the deepest living echinoderm?
They are abyssal sea cucumbers, and may be the deepest-living group of echinoderms : species of the genera Myriotrochus and Prototrochus (such as Prototrochus bruuni) have been identified down to 10,687 m (35,062 ft) deep.
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Q. What best describes an echinoderm?
Echinoderms are marine invertebrates. They include sea stars, sand dollars, and feather stars. Echinoderms have a spiny endoskeleton. They have radial symmetry as adults but bilateral symmetry as larvae.
Q. What makes something an echinoderm?
Echinoderms are named for the spines or bumps covering the outer surface of the bodies of many of them (Greek root word echino- meaning spiny; Latin root word -derm meaning skin). Examples of echinoderms include sea stars, sea urchins, sea cucumbers, brittle stars, and feather stars (Fig. 3.83).
Q. What best describes an annelid?
Annelids are segmented worms with a tubular body and a specialized digestive system with a terminal mouth and an anus. Their body cavity has thin transverse septa that delineate the segments. They generally reproduce sexually by cross-fertilization and are often hermaphroditic, but many reproduce asexually by budding.
Q. What best describes a mollusk?
Mollusk, also spelled mollusc, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body.
Q. What kind of muscles do annelids have?
1) Circular muscles run along under the epidermis, forming rings sometimes complete, at others incomplete ventrally or laterally. 2) All Annelida have longitudinal mus- cles which in Oligochaeta (Fig.
