eCHINODERMATA
Echinodermata , which contains about 6000 species, gets its name from the Greek, literally meaning "spiny skin." They are among the most distinctive of all animal phyla. Echinoderms are one branch of the deuterostome line of animal evolution, the branch to which Chordates also belong. To be included in the phylum is based upon these four characteristics: Calcitic skeleton composed of many ossicles, water vsacular system, mutable collagenous tissue, and pentaradial body organization in adults (radial symmatry). All echinoderms live in salt water, and they cannot live outside of water or in fresh water. Echinoderms also have a vascular system that carries water and which in some echinoderms end in suckered feet enabling the creature to grip and move objects.
Echinoderms differs from Arthropods as they have a water vsacular system, collagenous tissue, and body symmetry. Arthropods have a segmented body, jointed limbs, well developed nervous system, and an external skeleton. Also, Echinoderms do not have a chord, noto chord or spinal cord, where chordates do. In addition, echinoderms are radially symmetrical vs. arthropods' bilateral symmetry.
Echinoderms differs from Arthropods as they have a water vsacular system, collagenous tissue, and body symmetry. Arthropods have a segmented body, jointed limbs, well developed nervous system, and an external skeleton. Also, Echinoderms do not have a chord, noto chord or spinal cord, where chordates do. In addition, echinoderms are radially symmetrical vs. arthropods' bilateral symmetry.
DIGESTIVE SYSTEM
Echinoderms have a simple digestive system with a mouth, stomachs, intestine and anus. In many, the mouth is on the underside and the anus on the top surface of the animal.