Phylum echinodermata 2016
- 1. Phylum Echinodermata Ex. Sea stars, sea cucumbers, feather stars, sea urchins, sand dollars
- 2. Phylum Echinodermata 4 main classes: Class Asteroidea Class Ophiuroidea Class Echinoidea Class Holothuroidea
- 3. Echinoderms: • Name means “spiny skin” • Sea stars, sea cucumbers, sea urchins, etc. • All marine • All found on the bottom of the sea
- 4. Characteristics Phylum Echinodermata: • Body type: pentamerous radial (body radially symmetrical in 5 parts or multiples of 5) • Body organization: 3 layers: endoderm, mesoderm, ectoderm • Body cavity: coelom • Ecological roles: – Food source – Predator – control populations – Recycle nutrients – Chemicals-anticancer, antiviral
- 5. Characteristic continued: • Digestive system: – Complete – mouth & anus • Reproduction: – Sexual: - dioecious – Asexual: regeneration – if lost an arm or guts
- 6. Characteristics continued: • Circulation: closed • Nervous system: – nerve cords – No brain – Tube feet sensory • Respiration: tube feet & skin gills - diffusion • Excretion: diffusion, tube feet • Habitat: water - ocean
- 7. Endoskeleton: • Internal skeleton found within the tissues • It is always covered by a thin layer of tissue • Spines and bumps give reference to their name which means “spiny-skinned”
- 8. Dermal Branchiae • Soft bumps on the body that absorb oxygen from the water
- 9. Water Vascular System: • Has a water vascular system for movement, & structure (internal skeleton = endoskeleton)
- 10. Water vascular system network of canals which sea water circulates through = hydrostatic skeleton unique to Echinoderms
- 11. WATER VASCULAR SYSTEM OF A SEA STAR: Madreporite/ sieve plate: water enters vascular system Ring canal: surrounds mouth & leads to radial canals Radial canals: 5 of them – one down each arm Ampulla: muscular sac that controls tube feet by forcing water into it. Tube feet: create suction to adhere to substrate Movement, feeding ,excretion, respiration, sensory organ
- 12. Digestive System: • Sea urchins have a longer coiled intestine to allow time for the digestion of plant material • Sea cucumbers have a similar section to absorb nutrients from the sediment it ingests
- 13. Digestive System: • Sea and brittle stars can evert a portion of their stomach out of there mouth to engulf food • Digestive enzymes located in glands that extend into the arms
- 14. Regeneration/Autonomy: • The ability to grow lost or damaged body parts • Some times a severed arm can grow into a new organism if 1/5 of the central disc is present
- 15. Nervous System: • Limited knowledge on this aspect except for the presence of a nerve net • Ocelli – microscopic pigment spots on sea stars that can detect light and dark
- 18. Class Asteroidea • Includes: sea stars or starfish • Most have 5 arms from a central disk, though can have up to 50 • Each arm carries an equal share of organ systems
- 19. Class Asteroidea • Ambulacral grooves contain the tube feet on the arms
- 20. Class Asteroidea • Pedicellariae • Tiny pincer-like organs on the aboral side keep the surface clean • Most sea stars are predators of bivalves, snails, or other attached or slow moving animals
- 21. Class Ophiuroidea • Includes: Brittle Stars • Legs proportionally longer and thinner than sea starts • Allows for better movement • Organs in central disc • Tube feet lack suckers
- 22. Class Ophiuroidea • Eat organic matter and small animals they find on the bottom • Passed from tube foot to tube foot till it reaches the mouth
- 23. Class Echinoidea • Includes: Sea Urchins & Sand Dollars • Body structure forms a round, rigid body with movable spins and pedicellarie • Locomotion achieved by movable spines
- 24. Class Echinoidea • Body plan of sea stars repeated by moving arms upward and connecting them at the tips • Mouth is on the bottom, anus on the top • Spines: sharp, hollow and sometime contain venom
- 25. Plates: • 10 plates • Alternating abulacral (have openings for tube feet) and interambulacral (bumps for spines)
- 26. Class Echinoidea • The mouth has an intricate system of jaws and muscles called Aristotle’s Latern • Used to bite off algae and other bits of food from the bottom
- 27. Class Echinoidea • Heart Urchins and Sand Dollars are adapted for the soft bottom of the ocean • Flat bodies and short spines
- 34. Class Holothuroidea • Sea Cucumbers • Similar body plan to a sea urchin, just stretched out from mouth to anus • Lies on sides, oral and aboral surfaces are at the ends
- 36. Sea cucumber
- 39. Good echino playlist • https://www.youtube.com/playlist?list=PLQ5YDZy
Editor's Notes
- #3: Means spiny skinned
- #5: Predator – feed on sponges & molluscs
- #9: Closed – water vascular system No brain but have sensory organs including tube feet Excretion – diffusion, anus and tube feet
- #12: Endoskeleton – on the inside
- #13: Remember – water vascular system is echinoderm only
- #14: Sensory organ – can tast the water and locate food
- #38: Can reach up to 2 feet long! Used to make soup in the orient.
- #40: This Eyed (or Leopard) sea cucumber was upset with the way I handled it-- and has ejected sticky, white thread-like Cuvierian tubules from its anus. Fortunately this does no permanent harm to the sea cucumber, but the sticky threads are highly irritating to the skin if touched.
- #41: The sea cucumber has an interesting and slightly disgusting way of defending itself. Through self-evisceration, a sea cucumber can expel (throw out) all of its internal organs! This either scares off or satisfies predators. The cucumber can then grow another set of internal organs.