Echinoderm Review

Echinoderm

A phylum of marine animals characterized by their radial symmetry, a water vascular system, and a calcareous endoskeleton.

Adult starfish symmetry

Radial symmetry.

Arm of the starfish

Also known as a ray or arm.

Unique organ system of echinoderms

Water vascular system.

Muscle attached to tube feet in starfish

Ampullae.

Water vascular system functions

Involved in locomotion, feeding, respiration, and excretion. Not reproduction.

Class of sea stars

Asteroidea.

Example of Ophiuroidea

Brittle star.

Flattened immovable endoskeleton made of fused plates

Sea urchin.

Organism with 5 rows of calcified plates, eviscerating under stress

Sea cucumber.

Structure for water entry and exit in sea star water vascular system

Madreporite.

Madreporite location

Located on the aboral surface.

Benefits of radial symmetry

Provides equal access to the environment from all sides, allows for efficient feeding.

Feeding habits of Echinoidea

Most likely to feed on algae

Class with rigid test and spines

Echinoidea.

Common name for Crinoidea organisms

Sea lilies or feather stars.

Statement about echinoderm symmetry (False)

Not all echinoderms are radially symmetrical.

Impact of sea urchin population increase

Decreases algae population.

Feeding habit of sea cucumbers (False)

Sea cucumbers are not carnivores; they are detritivores.

Movement of sea lilies (False)

Sea lilies are sessile and not free-swimming.

Reproduction method of sea stars (False)

Sea stars can reproduce sexually and asexually, not only by regeneration.

Defensive mechanism of sea cucumbers

Expelling internal organs to distract predators.

Feeding method of sea stars (True)

Sea stars are carnivores that eat by inverting their stomachs.

Feeding method of sea urchins and sand dollars

They use their mouths to scrape algae off surfaces.

Short arm explanation in sea star

It is likely a result of injury or regeneration.

Sea star body plans

Radial symmetry and a central disc with arms.

Crown of thorns impact on coral

It is a type of starfish that destroys coral reefs.

Skeletal structure of echinoderms

Made of calcareous ossicles.