ECHINODERMATA ”Spiny Skin” DAN FITZPATRICK & ELIZABETH EZIRIKE

MAJOR CLASSES ASTEROIDERA Star shaped, arms radiate around central disk OPHIUROIDEA Distinct central disk, long brittle arms ECHINOIDEA Spherical, no arms, 5 rows of tube feet, mouth ringed HOLOTHUROIDEA 5 rows of tube feet, tube feet surround mouth act as feeding tentacles CRINOIDEA Feathered arms surround mouth suspension feeders suspension feeders CONCENTRICCYCLOIDEA Armless, disk shaped, incomplete DS

External Anatomy Tube Feet

Internal Anatomy: Starfish

Internal Anatomy: Sand Dollar

Internal Anatomy: Sea Cucumber

Type Of Symmetry Echinoderms have a combination of radial and bilateral symmetry. The symmetry of the larvae is bilateral, and the symmetry of the adult is radial, although not truly.

Life Cycle -Reproduction is sexual, through the use of larvae -Can reproduce asexually, through fission & regeneration

Distinguishing Characteristics  Water Vascular System  Tube Feet  Mouth, but no head or brain brain

INTERESTING FACTS  Sea stars have two stomachs: a cardiac stomach that helps them engulf food outside of their bodies and a pyloric stomach.  Sea baskets and brittle stars can be predators and can filter feed.  Echinoderms are found in oceans at all of the various levels including the deepest ocean trenches. They are not found on land or in freshwater.  Biologists believe that echinoderms can help discover medicines that cause human disease. Some are used for decoration and harvested as food.

ENDANGERMENT Humans pose the most danger to echinoderms and are responsible for most of the population decline. Over Harvesting Pollution – Road Pollution Most still thrive today.

Bibliography  AP Edition Biology – Eighth Edition (Reese, 1998, Pearson/Benjamin Cummings)  "Starfish, Sea Urchins and Other Echinoderms - Spiny-skinned Animals." Te Ara Encyclopedia of New Zealand. Web. 09 Feb  "Echinoderms." Acadia Oceanside Meadows Historic Inn, Downeast Maine Bed and Breakfast. Web. 09 Feb