Echinoderms Flashcards

Flashcards about Echinoderms

Echinodermata

Phylum meaning 'spiny skin,' characterized by spiny skins.

Echinoderm Symmetry

Radial symmetry (secondarily derived), bilateral larvae.

Echinoderm Habitat

Marine and brackish waters in all oceans and at all depths; mostly benthic.

Echinoderm Classes

Crinoidea, Echinoidea, Ophiuroidea, Asteroidea, Holothuroidea, Concentricycloidea.

Ossicles

Calcium carbonate components of the endoskeleton, varying in size and structure.

Podia

External part of tube feet used for locomotion, gas exchange, feeding, attachment, and sensory reception.

Class Asteroidea

Starfish, characterized by pentamerous radial symmetry, tube feet, and a water vascular system.

Asteroid Locomotion

Tube feet with ambulacra grooves for strong suction.

Asteroid Respiration

Cutaneous gas exchange.

Class Ophiuroidea

Brittle stars and basket stars with arms distinct from the central disc, closed ambulacral grooves, and tube feet without suckers.

Class Echinoidea

Sea urchins and sand dollars characterized by spines for protection and locomotion.

Aristotle's Lantern

Hard plates and muscles in urchins that control the protraction of five teeth for scraping algae.

Pedicellaria

Structures in echinoids and asteroids that respond to external stimuli, used for cleaning, protection, and camouflage.

Class Holothuroidea

Sea cucumbers with tentacles at their mouth openings and the ability to eject their intestines as a defense mechanism.

Sea Cucumber Feeding

Filter feeders using sticky slime on tentacles to grab particles from the ocean floor.

Class Crinoidea

Sea lilies with a water vascular system entirely of coelomic fluid and suckerless podia on pinnules.

Asexual Reproduction in Echinoderms

Regeneration of lost parts is common.

Sexual Reproduction in Echinoderms

Mostly gonochoristic with gonads housed in genital sinuses.

Isolecithal Egg

Echinoderm egg with a small amount of yolk undergoing radial holoblastic cleavage.