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Portia Ophioderma rubicundum

Brittle Star

Classification of animal in Phylum

• five well-defined clases: • Crinoidea (sea lilies and feather

stars),• Ophiuroidea (basket stars and brittle

stars) • Asteroidea (starfishes)• Echinoidea (sea urchins, sand dollars,

and sea biscuits)• and Holothuroidea (sea cucumbers).

Body form

Spiny-skinnedOr wart-like bumpssymmetricalCan loose up to 3 limbs

Reproduction

• Echinoderms have the ability to regenerate new parts asexually.

• They also have separate sexes with reproductive organs in each arm.

• Sexual reproduction involves releasing gametes into the water (external fertilization).

• Seahorses: males give birth

Digestive System

Urchins are herbivores (they eat plants)

starfish are predators and scavengersother feed on waste.

Respiratory System

• Gills on the skin which exchange gases

Living Environment

• Mainly marine environment

• Live in slightly salty water

• Live in shallow and deep waters.

Circulatory System

Open circulatory system

Cilia circulates fluids through the arms.

Interaction with humans

• They are more related to humans than any other invertebrate.

Unique Features

• External skeletons

• There is no head

• Usually have mouth on the underside

• Anus usually on top

Pictures!!

Sea Urchin

Sea Cucumber

Basket Star

Citing

  Various Authors. Think Quest. May 21, 2009.

<http://library.thinkquest.org/28751/review/animals/7.html>