echinoderms. phylum echindermata share common features with chordatesshare common features with...
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Phylum EchindermataShare common features with chordatesRadial CleavageDeuterostomes (Blastopore becomes anus)Development of true coeloemUsually slow moving or sessileUsually are radially symmetricalBody parts usually radiate from center (frequently as 5 spokes)Possess a thick calcium plate endoskeleton surrounded by a thin skin layerPossess a unique Water Vascular System, which continues throughout animal and extends into extensions called Tube Feet.Functions for locomotion, feeding, & gas exchange.Reproduce sexually or through regeneration.
Class AsteroideaInclude sea starsUsually have 5 (or multiple of 5) arms radiating from central diskTube feet located underneath each arm used for locomotion & grasping prey. Operate by hydraulic principles.
Anatomy of a Sea Star
FeedingFeed on mollusks by pulling shells apart and extending stomach outside the mouth into the bivalve. The bivalve is digested within it's shell. The sea star than re-ingests its stomach
ReproductionCan reproduce sexually by releasing sperm and egg.Can reproduce by regeneration
Class Ophiuroidea Include Brittle StarsDistinct central disks with long tube-like armsLack suckersMove by serpentine motion of their arms
Class EchinoideaInclude Sea urchins & sand dollarsLack arms, but possess tube feetMany species of urchins possess poisonous spines used for defense
EchinoideansSand DollarSea Urchin
Class HolothuroideaInclude Sea cucumbersAre elongated along oral-anal axisLack spines and have reduced endoskeleton.Do possess tube feet and water vascular system
Class CrinoidiaAncient class of animalsInclude sea liliesFilter feeders with arms radiating from mouthMost are sessile, but some can move