Echinodermata Flashcards

Vocabulary flashcards for reviewing Echinodermata lecture notes.

Echinodermata

A phylum of marine animals characterized by radial symmetry, including starfish, brittle stars, sea urchins, and sea cucumbers.

Radial Symmetry

The five-point symmetry seen in echinoderms, with arms projecting outwards around a central axis.

Pentameral Symmetry

A type of symmetry found in some worm-like echinoderms with five-fold symmetry.

Water Vascular System

A unique system in echinoderms that uses seawater to convey nutrients and gases throughout the body.

Madreporite

A plate through which most echinoderms obtain water.

Endoskeleton

An internal skeleton composed of calcium carbonate components known as ossicles.

Ossicles

Calcium carbonate components that make up the endoskeleton of echinoderms.

Pedicellariae

Jaw-like structures often at the end of stalks of urchins and sea stars used for defense and food capture.

Cardiac Stomach

The stomach that digests the tissue of captured prey while it is still outside the body of sea stars.

Pyloric Stomach

The internal stomach that further digests food and processes nutrients throughout the body of sea stars.

Tube Feet

Water-filled appendages found on the bottom of many echinoderms' bodies used for movement.

Lunules

Visible slits in the body of some sand dollars that radiate from their center, helping them to stay in place in turbulent water.

Cirri

Small “legs” on feather stars that keep them attached to the sea bottom.

Toxopneustes

The flower urchin, known for its extremely toxic pedicellariae.

Saponin

A bitter-tasting compound found in the skin of sea stars that deters fish and other predators.

Tetrodotoxin

A highly toxic chemical produced by some sea stars that disrupts nerve signals.

Regeneration

The ability of echinoderms to lose an appendage and grow it back.

Fission

When a sea star or brittle star spontaneously splits, often as a means of asexual reproduction.

Eleutherozoa

Two major subdivisions recognized in the Phylum Echinodermata characterized by being motile (able to move).

Pelmatozoa

Two major subdivisions recognized in the Phylum Echinodermata characterized as being sessile (stuck in place) but some are motile.