1. Phylum Echinodermata “Spine skin” Marine (or estuarine) Water vascular system Pentaradial symmetry

2. Echinodermata 6500 species living 13,000 from fossils Classes: Crinoidea, Stelleroidea, Echinoidea, Holothuroidea

3. Water vascular system Fluid-filled canals that lead to tube feet Sea star: madreporite, stone canal, ring canal, radial canal, ampulla, tube feet

4. Water vascular system Tiedemann’s body: Contains phagocytes; remove foreign matter such as bacteria from incoming seawater

5. Water vascular system Ambulacral ossicles support ampullae and tube feet Contraction of ampulla moves fluid to tube feet Muscles in tube feet for retracting http://www.youtube.com/watch?v= HPhAGyDceLo

6. Water vascular system Cilia on inner surface of tube feet circulate water Gas exchange Fluid similar to seawater; contains coelomocytes, proteins, K ions

7. Class Crinoidea Lily-like Feather stars and sea lilies Oldest of living echinoderms

8. Class Crinoidea Feeding, repro structures at top of stalk Complete digestive system in calyx: mouth – intestine, anus http://www.youtube.com/wat ch?v=s1xfRc4SDsw

9. Class Crinoidea Arms have ambulacral groove with mucus- secreting glands adjacent. Food particles stick in mucus, flicked to the ambulacral groove, then mouth

10. Class Stelleroidea Armed echinoderms Brittle stars, sea stars

11. Brittle stars and basket stars ~ 2100 described Joints allow flexibility Tube feet present Sensitive to light – oral surface http://www.youtube.com/watch?v= mj8ZYysrmxU

12. Brittle stars and basket stars Tube feet through small holes Digestive system mostly in disc – no anus Bursal slits for water exchange

13. Deposit feeders, suspension feeders, carnivores, scavengers Many are nocturnal Many live in associations Brittle stars and basket stars

14. Sea stars ~ 1600 species Arms not as distinct from disc as in brittle stars Move slowly with tube feet Tube feet move individually

15. Figure 20_06

16. Sea stars Digestion: lower cardiac stomach digests food Upper pyloric stomach for secreting enzymes and absorption

17. Pedicellariae: stalked or sessile

18. Figure 20_09

19. Concentricycloids – sea daisies Recently (1986) discovered echinoderms > 1000 m New Zealand, Bahamas –Tube feet arrangement different

20. Class Echinoidea: spine-like Sea urchins, sand dollars < 1000 species

21. Class Echinoidea: spine-like Ossicles form test Complex system of ossicles and muscles for grazing = Aristotle’s lantern

22. Spines attach to skeleton – ball and socket joint Toxins Ossicles flat and joined = inflexible

23. Class Echinoidea: spine-like Tube feet in 5 double rows of plate Pedicellariae – globular forms have toxin

24. Feeding and digestion: Aristotle’s lantern Teeth protruded to scrape algae or consume food Species w/o lantern usually detritivores

25. Mouth – esophagus – intestine – anus WVS http://www.youtube.co m/watch?v=D3W4OCn HyCs

26. Class Holothuroidea: sea cucumbers ~ 1200 species

27. Ossicles microscopic Multiple shapes

28. Tube feet modified into tentacles around mouth Mostly deposit-feeders, few filter-feeders

29. Digestion system: elongated Mouth – esophagus – stomach – intestine – cloaca – anus WVS – madreporite in coelomic cavity = no outside connection

30. Respiratory tree: connects to cloaca – water supply Expulsion of internal organs

31. Echinoderm repro + development: Some are asexual Most are dioecious Multiple gonads, gametes into seawater = external fert

32. Distinctive ciliated larval form in each class Free-swimming, planktonic Metamorphosis into adult

33. Echinoderm NS No brain 3 nerve networks Ectoneural = ring around esophagus: receives sensory input

34. Echinoderm NS Hyponeural = circumoral nerve: motor function Entoneural = associated with aboral end, neurons from stalk down arms