Starfish - Echinoderms

Classification

There are five main classes of Echinoderms:

  1. Sea Stars or starfish (Asteroidea)
  2. Brittle stars, basket stars, serpent stars (Ophiurodea)
  3. Sea urchins, heart urchins and sand dollars (Echinoidea)
  4. Holothurians or sea cucumbers (Holothuroidea)
  5. Feather stars and sea lilies (Crinoidea)

            

Sea stars or starfish are classified as follows:

  • Kingdom : Animalia
  • Phylum : Echindermata
  • Class: Asteroidea

Echinodermata means 'spiky skin' and Asteroidea means 'star-like'. There are seven orders of starfish and about 1500 living spacies. All are marine.

Characteristics

Charateristics of Echinoderms include:

  • radial symmetry

  • several arms radiating from a central body (5 or more, mostly grouped 2 left, 1 middle and 2 right)

  • body consists of 5 equal segments each of which contain a duplicate set of internal organs

  • have no heart, brain or eyes (starfish have eyespots)

  • have small structures called tube feet with suction cups on the ends that are hydraulically controlled



Website created by Jenny Stevenson - June 2006.