Phylum Echinodermata
The Spiny Skin Animals
• Examples: Sea Stars, Brittle Stars, Sea Urchins, Sea Cucumbers, Sea Lilies, & Feather Stars
Pentamerous radial symmetry
•
___________________________________________________________________________
Water Vascular System
• Unique organ system that water-filled tube and water pressure for both locomotion and
feeding.
• System of tubes end in tube feet.
Internal Skeleton
• Consists of plates ________________________________________ (CaCO3).
• Plates are often studded with spines, hence their name.
• Typically divisible in __________________ parts
Bottom Dwellers
• ____________________________________
• Most abundant on rocky shores
• Can be found in every ocean, at all depths
Class Asteroidea:
• Found from subtidal to deepest part of ocean
• Five appendages (arms) radiating from a central axis
• Eat _________________ and are considered ___________________ by seafood industry
• Examples:
•
Bat Star (Pateria)- W. Coast, Kelp beds
•
Sun star (__________________________)- 10 –15 arms, eat other sea stars
Respiration
• _______________________- ciliated finger-like projections on the dorsal surface of the skin
• Breathe through their skin and ___________________________
• __________________________- fluid filled sac lined with cilia that beat and circulate water.
Diffuse ___________________________________________
Feeding and Locomotion
• Arms are used for locomotion and getting food.
• Carried out by the _______________________________________________
• Water enters the _________________________________(sieve plate)  Ring Canal
Radial Canal Tube feet
• Tube feet are delicate projections attached along the side of the radial canal in a groove
• _________________________________- top of the tube foot, resembles a medicine dropper.
• Feet suction to surfaces. Allows sea stars to attach to bivalves and pull open shells by tugging
for hours therefore weakening the ________________________________________.
• Sea star pushes its stomach out through the mouth and digests the food _________________.
Label the anatomy of a Starfish on the following page.
Response
• _____________________________________- tiny light receptors located at the end of each
arm. Light is converted into electrical impulses that are carried to _____________________
__________________________ around the mouth which then directs the arms.
Reproduction
• ___________________________________________
• Gonads are located inside each arm near the central disk.
• Fertilization and development occur _______________________________________
Regeneration
• Sea stars can regenerate new arms if cut off
• A new Sea Star can grow from an arm as long as part of the
__________________________is present.
Class Echinoidea : ___________________________________________
• Oval or round bodies; lack arms; use spines and tube feet to move; eat algae off rocks using
______________________________ (5-toothed mouth structure)
Protection and Predation
• Use spines to wedge themselves into spaces between rocks; protects from wave action and
predators (except California Sea Otter!)
Reproduction
• Similar to sea star
• Used for embryological studies because of blastula phase of urchin.
Sand Dollars and Sea Biscuits
• _________________: short spines cover its skin; burrow in sand and feed on plankton.
• __________________: more rounded body; longer spines; lives around coral reefs.
Class Ophiuroidea: _____________________________
• Solitary, nocturnal creatures that hide under rocks during the day.
• Found in intertidal zone to the deep; from tropics to Arctic
• Use long muscles in long, skinny arms in order to
scurry rapidly about on the sea floor.
• Can detach appendages when attacked.
Class Crinoidea: ________________________________________________________
• Most ancient of echinoderms
• Have feathery appendages to catch food (____________________)
• Limited movement. Sea lilies are sessile; Sea feathers slowly crawl on
coral reefs.
Class Holothuroidea: _______________________________
• Soft, oblong body w/no arms_____________________________; no endoskeleton or spines;
only have small bony pieces in the skin
• Use sticky branching tentacles (enlarged tube feet) to trap microscopic organisms. Extend
around mouth during feeding and retracted when disturbed.
• No skin gills- take in and release water thru anus and gas exchange occurs in the coelom
across membranes call the “_________________________”
• If attacked, SC will release its digestive organs to leave a meal for the predator and escape.