1. Unit 7
Phylum: Echinoderms

3. I. Sea Stars A. Sea Star Structures
Appendages- usually 5 or multiples of 5 radiating from a central body
Endoskeleton- the internal skeleton
3. Spines- Found on the skin
-Help support and protect sea star
-Made of calcium carbonate

5. 4. Coelom
Fluid filled spaces under the skin (on dorsal side)
Are lined with skin gills

6. 5. Skin gills
Small, cilliated finger-like projections
Help with breathing
Found on the coelom

8. 6. Suction discs
Found at the end of each arm
Used to cling to hard surfaces

10. B. Feeding in Sea Stars Some feed on detritus (-Organic matter)
Most are carnivores (sponges, mollusks etc.)
Surrounds the prey (clam etc.), and pulls on it until it weakens and opens
The stomach is extended over the prey
Digestive juices are secreted
Prey’s tissues are liquefied
The digested food and stomach are sucked back in.

11. C. Locomotion in Sea Stars
Have a water vascular system (-water filled canals and tubes)
Water enters the sieve plate (on dorsal side)
Water travels through radial canals in each arm
Water enters tube feet which are on radial canals
The contraction and release of tube feet help the star move and grasp objects

12. D. Reproduction in Sea Stars
Sexual: Have separate sexes
-Fertilization is external (sperm and egg released into water)
-Development is external

13. Asexual: Through regeneration
-if an area is torn off and part of the central disc is left, a whole new star can form

15. II. Sea urchins Structures of the sea urchin
1. Spines- Sharp, pointed, can be venomous
2. Aristotle’s lantern- centrally located mouth structure, used to scrape algae
3. Tube feet- Used to help it move

16. B. Feeding in Sea urchins
1. Most graze on algae
2. Some feed on sponges and other small animals
**Many sea urchins in an area can be a sign of bad water conditions

18. C. Locomotion in Sea urchins
1. Use tube feet
2. Also use the small spines on the underside of the body

19. D. Reproduction in Sea urchins
-is Sexual and external
-Are zooplankton as larvae
-From fertilization to adult is 2-5 years

21. III. Brittle Stars

22. A. Movement in brittle stars
1. Have muscles in the skinny arms to help with movement

24. B. Behavior of brittle stars
1. Are nocturnal
2. Are solitary (live alone)
3. Can detach (or let go of) an appendage when attacked

26. C. Feeding in brittle stars
Use arms to gather debris off seafloor
Or…
2. Filter feed

30. IV. Sand dollar 1. 5 Part Radial Symmetry
A. Structures:
1. 5 Part Radial Symmetry
2. Hard skin made of calcium carbonate

32. 3. Bottom (ventral side) has mouth,. spines and cilia (all for getting
3. Bottom (ventral side) has mouth, spines and cilia (all for getting food)
4. Tube feet are used as gills

36. V. Sea cucumber
A. Body 1. soft, oblong body 2. tube feet arranged in 5 rows across the body tentacles around the mouth

37. Fast Facts Type: Invertebrate Diet: Omnivore
Average life span in the wild:
5 to 10 years
Size:
0.75 in to 6.5 ft (2 to 200 cm)
Size relative to a 6-ft (2-m) man:
                    

39. Tropical Sea Cucumber

40. Diet
1. eat decaying matter off seafloor
Leopard Sea Cucumber

41. When threatened, some sea cucumbers discharge sticky threads to ensnare their enemies.
Others can mutilate their own bodies as a defense mechanism. They violently contract their muscles and jettison some of their internal organs out of their anus.
The missing body parts are quickly regenerated.

42. Video -- Animals, Travel, Kids -- National Geographic

44. VI. Sea Lilly
A. The most ancient echinoderms B. Have feathery arms on jointed stalks C. Are sessile (don’t move around)

47. VII. Feather star
A. crawl or swim in a limited manner across the bottom B. Feed by waving arms and capturing zooplankton