Radial symmetry: PENTARADIAL Bilateral in free swimming embryonic

stages

200 arms Comanthina schlegelii

Rare species have 6 arms

endoskeleton made of tiny calcareous plates and spines (OSSICLES)

Acts like exoskeleton but its NOT! always contained within a layer of living tissue

Mutable Connective Tissue (MCT) :has special ability to be converted from stiff to soft in an instant

Hydraulic network of fluid-filled canals Water enters the MADREPORITE Very powerful, but slow

Gas exchange Feeding Locomotion

Bumps and spines let in oxygen Skin is very thin: oxygen can diffuse in

from the surrounding water

No brain Nerve ring surrounding the gut Radial nerves run under the ambulacra Sensory neurons are located primarily

within the ectoderm of podia

External Fertilization Separate sexes Reproductive organs in each arm Some species brood their young

100,000,000 eggs at once

Fission of body parts Regeneration: spines, arms,

intestines

ECHINODERMS

ASTEROIDEA

CRINOIDEA

ECHINOIDEA

HOLOTHUROIDEA

OPHIUROIDEA

1

23 41. CHARACTERISTI

C2. CHARACTERISTI

C3. CHARACTERISTI

C4. SPECIES

A. DESCRIPTIONB. WHERE FOUNDC. COLOR/SHAPE

A

B

C

• Kingdom Animalia•Phylum Echinodermata Class Asteroidea Class Echinoidea Class Holothuroidea Class Ophiuroidea Class Crinoidea

Mostly benthic carnivores Eye spots: end of each arm. Tube feet have suckers, which

chemically adhere to the substrate. Another chemical bond is secreted to release the tube feet.

Keep animal free from encrusting organisms

May contain toxins Protect the papulae: skin gills

Some may use pedicellariae to aid in food capture

Evert stomach and secrete primary enzymes on the prey.

The digestive juices break down the tissue of the prey, which the asteroids then suck up.

http://www.pbs.org/kcet/shapeoflife/episodes/ulti_explo2.html

Ossicles overlap and are fused into test

Urchins also have pedicellariae

“Urchin Barren”-destruction of kelp beds by unchecked urchins

Grazers: algae Powerful chewing apparatus called

the Aristotle's lantern- five jaws

http://www.biology.ualberta.ca/facilities/multimedia/uploads/zoology/Aristotle.swf

http://video.nationalgeographic.com/video/player/animals/invertebrates-animals/other-invertebrates/sea_urchin_breeding.html

Branching tentacles surround the mouth Respiratory trees near anus Suspension/deposit feeders They cycle up to 90% benthic biomass in ocean Defense: skin secretes toxins and they can

expel organs (autotomic evisceration) http://video.nationalgeographic.com/video/player/kids/animals-pets-kids/

invertebrates-kids/sea-cucumber-kids.html

Move quickly moving arms Arms are long, slender, and flexible Ability to autotomize: spontaneous casting

of limb No suckers on tube feet-some have mucus

to help them stick to things and capture prey

Five jaws

Most live in deep sea Feather Stars: some are free swimming Sea Lillies: most are sessile- only attached

suspension-feeding echinoderms Cirri used to attach or grab substrate Brood their young http://encarta.msn.com/media_461543142/

feather_star.html

Filter Feeders (mostly deep sea OM) Cirri used to attach

or grab substrate