1. Phylum Echinodermata
Sea stars, brittle stars, sea urchins, sea cucumbers, sand dollars

2. The Basics Echinodermata Echinodermata means “spiny skin”
About 7000 species – all marine
Planktonic larvae are bilateral
Adults are radially symmetrical
Pentamerous – symmetry based on 5 parts
They have an oral (mouth) side and an aboral side
Have an endoskeleton
Possess a water vascular system
Tube feet usually have suckers and are used for attachment, locomotion, and receiving chemical and mechanical stimuli

3. The Types – Sea Stars Echinodermata
Most species have 5 arms that radiate around a central disk
Some species can have up to 50 arms
Hundreds of tube feet cover the oral surface
Can move in any direction by reaching out their tube feet and pulling themselves along
Endoskeleton consists of interconnected calcium carbonate plates that form a relatively flexible framework
Allows their arms to be somewhat flexible
Aboral surface is often covered with spines
Feed on bivalves, snails, barnacles, and any other attached or slow moving animal

4. Echinodermata – Sea Stars
Ochre Sea Star
Northern Pacific Sea Star
Sun Star
Echinodermata – Sea Stars
Cushion Sea Star
Goose Foot Sea Star
Common Sea Star
Spiny Sea Star
Crown of Thorns
Sand Star

5. The Types – Brittle Stars
Echinodermata
Have 5 arms that are long, very flexible, and sharply defined from the central disk
The snake-like arms are used in locomotion
The tube feet (lacking suckers) are used for feeding
Most eat detritus and small animals they pick up from the bottom
Largest group of echinoderms as well as the most widely distributed

6. Echinodermata – Brittle Stars
Blunt Spined Brittle Star
Banded Brittle Star
Echinodermata – Brittle Stars
Green Brittle Star
Millipede Brittle Star
Heart Brittle Star
Ruby Brittle Star

7. The Types – Sea Urchins Echinodermata
Endoskeleton forms a round, rigid, shell- like test with movable spines
Locomotion is achieved by the movable spines, jointed to sockets in the test, and the sucker-tipped tube feet
Graze on seaweeds and seagrasses, but will also ingest detritus
Mouth has an intricate system of jaws and muscles called Aristotle’s Lantern
Used to bite off algae and other bits of food from the bottom
Found worldwide on rocky shores

8. Echinodermata – Sea Urchins
Long Spined Urchin
Pencil Urchin
Echinodermata – Sea Urchins
Black Hatpin Urchin
Crown Urchin
Boring Urchin
Fire Urchin

9. The Types – Sea Urchins Echinodermata
Sand dollars and heart urchins are closely related to urchins
Flattened bodies with shortened spines, deposit feeders

10. The Types – Sea Cucumbers
Echinodermata
The animal lies on one side, where the 5 rows of tube feet are concentrated
The oral and aboral surfaces are at the ends
Endoskeleton consists of microscopic, calcareous spicules scattered through the warty, often tough, skin
Deposit feeders
Tube feet around the mouth are modified into tentacles that are used to scoop food into mouth
Lack spines so they have other defense mechanisms: secretion of toxic substances, expulsion of internal organs

11. Echinodermata – Sea Cucumbers
Chocolate Chip Sea Cucumber
Echinodermata – Sea Cucumbers
Beaded Sea Cucumber
Sea Apple Sea Cucumber
Pink Warty Sea Cucumber

12. The Types - Crinoids Echinodermata
Suspension feeders that use outstretched, feathery arms to obtain food from the water
Includes feather stars and sea lilies
Capable of swimming
Body plan is best described as an upside- down brittle star with the mouth directed upward
Some only have 5 arms, while others may have up to 200 arms (because of branching of the initial 5 arms)
Tiny tube feet secrete a mucus to aid in catching food particles

13. Echinodermata - Crinoids

14. Digestion and Feeding Echinodermata
Sea stars are carnivorous and extend their stomach inside out through the mouth to envelop the food
Sea urchins and sea cucumbers have long and coiled guts
Sea urchins need the long gut in order to digest plant material
Sea cucumbers need the long gut in order to process large amounts of sediments to obtain enough organic matter for survival

15. Sea Star with expelled stomach
Echinodermata

16. Respiration and Circulation
Echinodermata
Have a water vascular system, which is a system of internal tubes filled with fluid
Moves water, nutrients, gases, and wastes throughout the body
Tube feet are the main surface for respiration (gas exchange)

17. Water Vascular System
Echinodermata

18. Excretion Echinodermata
Digestive wastes are released as feces through the anus
Nitrogen-containing cellular wastes are excreted in the form of ammonia
This waste is passed into surround water through the tube feet and skin

19. Nervous System Echinodermata Very simple
Have a nerve ring that surrounds the mouth and radial nerves that connect the ring with the body parts
Do not have a brain
Coordinates movements of tube feet and spines
Most have scattered sensory cells that detect light, gravity, and chemicals released by potential prey
Many have the ability to turn their bodies over after being flipped
Sea urchins have also been known to camouflage their bodies with debris

20. Echinodermata

21. Reproduction Echinodermata Most species have separate sexes
Mostly external fertilization through spawning
Developing larvae become part of the plankton
Some sea stars, brittle stars, and sea cucumbers regularly reproduce asexually by the separation of the central disk/body into two pieces
Each piece then grows into a complete individual
Regeneration – the ability to regrow lost arms and damaged body parts

22. Echinodermata

23. Echinoderms: the ultimate animal Video 14 min
Echinodermata
inoderms-ultimate-animal