Echinoderms. Phylum Echindermata Share common features with chordatesShare common features with chordates Radial CleavageRadial Cleavage Deuterostomes.

EchinodermsEchinoderms

Phylum EchindermataPhylum Echindermata

•Share common features with chordatesShare common features with chordates•Radial CleavageRadial Cleavage•Deuterostomes (Blastopore becomes anus)Deuterostomes (Blastopore becomes anus)•Development of true coeloemDevelopment of true coeloem

•Usually slow moving or sessileUsually slow moving or sessile•Usually are radially symmetricalUsually are radially symmetrical

•Body parts usually radiate from center (frequently as 5 Body parts usually radiate from center (frequently as 5 spokes)spokes)

•Possess a thick calcium plate endoskeleton surrounded by a Possess a thick calcium plate endoskeleton surrounded by a thin skin layerthin skin layer•Possess a unique Possess a unique Water Vascular SystemWater Vascular System, which continues , which continues throughout animal and extends into extensions called throughout animal and extends into extensions called Tube Tube FeetFeet..

•Functions for locomotion, feeding, & gas exchange.Functions for locomotion, feeding, & gas exchange.•Reproduce sexually or through regeneration.Reproduce sexually or through regeneration.

Class Class AsteroideaAsteroidea

Include sea starsInclude sea stars Usually have 5 (or Usually have 5 (or

multiple of 5) arms multiple of 5) arms radiating from central radiating from central diskdisk

Tube feet located Tube feet located underneath each arm underneath each arm used for locomotion & used for locomotion & grasping prey. grasping prey. Operate by hydraulic Operate by hydraulic principles.principles.

Anatomy of a Sea StarAnatomy of a Sea Star

FeedingFeeding

Feed on mollusks Feed on mollusks by pulling shells by pulling shells apart and apart and extending stomach extending stomach outside the mouth outside the mouth into the bivalve. into the bivalve. The bivalve is The bivalve is digested within it's digested within it's shell. The sea star shell. The sea star than re-ingests its than re-ingests its stomachstomach

ReproductionReproduction

Can reproduce Can reproduce sexually by sexually by releasing sperm releasing sperm and egg.and egg.

Can reproduce by Can reproduce by regenerationregeneration

Sea StarsSea Stars

Class Class OphiuroideaOphiuroidea

Include Brittle Include Brittle StarsStars

Distinct central Distinct central disks with long disks with long tube-like armstube-like arms

Lack suckersLack suckers Move by serpentine Move by serpentine

motion of their motion of their armsarms

Brittle StarBrittle Star

Class Class EchinoideaEchinoidea Include Include Sea urchinsSea urchins & & sand dollarssand dollars Lack arms, but possess tube feetLack arms, but possess tube feet Many species of urchins possess poisonous Many species of urchins possess poisonous

spines used for defensespines used for defense

EchinoideansEchinoideans

Sand DollarSand Dollar Sea UrchinSea Urchin

Class Class HolothuroideaHolothuroidea

Include Sea Include Sea cucumberscucumbers

Are elongated Are elongated along oral-along oral-anal axisanal axis

Lack spines Lack spines and have and have reduced reduced endoskeleton.endoskeleton.

Do possess Do possess tube feet and tube feet and water vascular water vascular systemsystem

Sea CucumberSea Cucumber

Class Class CrinoidiaCrinoidia

Ancient class of Ancient class of animalsanimals

Include Include sea sea lilieslilies

Filter feeders Filter feeders with arms with arms radiating from radiating from mouthmouth

Most are Most are sessile, but sessile, but some can movesome can move

CrinoidsCrinoids