The World of Invertebrates: Echinoderms (Asteroids & Crinoids)

Vocabulary flashcards covering the characteristics, anatomy, vital functions, and classification of Asteroids and Crinoids based on the lecture notes.

Echinoderms

A unique group of invertebrate marine animals known for their spiny skins, radial symmetry, and exclusive residence in salt water; the name comes from the Greek words "echinos" (spiny) and "derma" (skin).

Asteroids

Star-shaped echinoderms known as "star fish" that usually have a central disc and five arms, with the ability to regenerate lost limbs.

Crinoids

Echinoderms that look like plants or flowers, featuring a cup-like body with feathery arms used to catch food from the water.

Asterias Rubens

The scientific name for the Common Starfish.

Choriaster Granulatus

The scientific name for the Granulated Sea Star.

Cenocrinus asterius

The scientific name for the Sea Lily, a type of crinoid that typically lives in deep seas.

Antedon mediterranea

The scientific name for the Mediterranean Feather Star, a type of crinoid commonly found on coral reefs.

Central Disc

The center of the asteroid body where the arms are attached.

Madreporite

A pressure-equalizing valve in asteroids that allows water into the vascular system.

Tube Feet

Small suction cups found on asteroids used for walking and opening shells.

Stomach (Asteroids)

An organ of which starfish have two; they can push one outside the body to digest prey.

Pinnules

Feathery structures located on the arms of crinoids that trap small food particles.

Calyx

The central cup-shaped body of a crinoid that contains the internal organs.

Stalk

A structure used by sea lilies to attach themselves to the sea floor.

Cirri

Appendages used by crinoids to grip onto rocks.

Heterotrophs

Organisms, including both asteroids and crinoids, that live from organic matter in the ocean.

Filter Feeders

Specifically referring to crinoids, which eat tiny plankton from water currents.

Water Vascular System

A system used by both asteroids and crinoids, in conjunction with a nervous ring, to move since they lack a brain.

External Fertilization

The reproductive process used by both asteroids and crinoids where eggs and sperm are released into the water.

Regeneration

The capacity to grow back lost body parts; in some asteroids, a single broken arm can grow into a completely new starfish.

Class Asteroidea

The taxonomic classification for star-shaped echinoderms like the Common Starfish.

Class Crinoidea

The taxonomic classification for echinoderms such as Sea Lilies and Feather Stars.