1. Phylum Echinodermata
Marine Invertebrates

2. Characteristics All marine Known as spiny-skinned animals
Endoskeleton known as the test is made of calcium plates or ossicles with protruding spines
Includes sea stars, brittle stars, sand dollars, sea urchins, & sea cucumbers

3. Characteristics
Bipinnaria Larva
Undergo metamorphosis from bilateral, free-swimming larva to sessile or sedentary adult
Larval stage known as dipleurula or bipinnaria
Adults have pentaradial (5 part) symmetry
Lack segmentation or metamerism

5. Characteristics Coelomate Breathe through skin gills as adults
Capable of extensive regeneration

6. Characteristics
Ventral (lower) surface called the oral surface & where mouth is located
Dorsal (upper) surface known as aboral surface & where anus is located
Have a nervous system but no head or brain in adults
No circulatory, respiratory, or excretory systems

7. Characteristics
Have a network of water-filled canals called the water vascular system to help move & feed
Tube feet on the underside of arms help in moving & feeding
One-way digestive system consists of mouth with oral spines, gut, & anus
Deuterostomes (blastopore becomes the anus)

9. Characteristics Separate sexes Reproduce sexually & asexually
In sexual reproduction, eggs (up to several million) from females and spermatozoa from males are shed into the water (spawning), where the eggs are fertilized. Most echinoderms spawn on an annual cycle, with the spawning period normally lasting one or two months during spring or summer; several species, however, are capable of spawning throughout the year. Spawn-inducing factors are complex and may include external influences such as temperature, light, or salinity of the water.

10. Includes 5 classes: Crinoidea - sea lilies & feather stars
Asteriodea - starfish
Ophiuroidea - basket stars & brittle stars
Echinoidea - sea urchins & sand dollars
Holothuroidea - sea cucumbers

11. 1) Crinoidea Characteristics
Sea lilies & feather stars
Sea lilies have a long stalk with branching arms that attach them to rocks & the ocean bottom
Feather stars can detach & move around
Mouth & anus on upper surface

12. 1) Crinoidea Characteristics
May have 5 to 200 arms with sticky tube feet to help capture food (filter feeders) & take in oxygen
Common in areas with strong currents & usually nocturnal feeders

13. 2) Asteroidea Characteristics
Usually sedentary along shorelines
Starfish or sea stars
Come in a variety of colors
Prey on bivalve mollusks such as clams & oysters

14. 2) Asteroidea Characteristics
Have 5 arms that can be regenerated
Arms project from the central disk
Mouth on oral surface (underside)
Range in size from  1 cm to 1 m

15. Body Plan of Sea Star Have an endoskeleton made of calcium plates
Sharp, protective spines made of calcium plates called ossicles found under the skin on the aboral (top) surface
Have pedicellariae or tiny, forcep-like structures surrounding their spines to help clean the body surface
Aboral Surface

16. Water Vascular System
Network of canals creating hydrostatic pressure to help the starfish move
Water enters through sieve plate or madreporite on aboral surface into a short, straight stone canal
Stone canal connects to a circular canal around the mouth called the ring canal

17. Water Vascular System
Five radial canals extend down each arm & are connected to the ring canal
Radial canals carry water to hundreds of paired tube feet

18. Water Vascular System

19. 3) Class Ophiuroidea Largest class of echinoderms
Includes basket stars & brittle stars
Live on the ocean bottom beneath stones, in crevices, or in holes

20. 3) Class Ophiuroidea
Have long, narrow arms resembling a tangle of snakes
Arms readily break off & regenerate
Move quicker than starfish
Feed by raking in food with arms or trapping it with its tube feet

21. 4) Class Echinoidea Includes sea urchins & sand dollars
Internal organs enclosed by endoskeleton or test made of fused skeletal plates
Body shaped like a sphere (sea urchin) or a flattened disk (sand dollar)
Lack arms

23. 4) Class Echinoidea Bodies covered with movable spines
Have a jawlike, crushing structure called Aristotle's lantern to grind food
Use tube feet to move

24. 4) Class Echinoidea Spherical shape Live on ocean bottom
Scrape algae to feed
Long, barbed spines make venom for protection

25. 4) Class Echinoidea Flattened body Live in sand along coastlines
Shallow burrowers
Have short spines

26. 5) Class Holothuroidea Includes sea cucumber Lack arms
Shaped like a pickle or cucumber
Live on ocean bottoms hiding in caves during the day 
Have a soft body with a tough, leathery outer skin

28. 5) Class Holothuroidea
Five rows of tube feet run lengthwise on the aboral (top) surface of the body
Have a fringe of tentacles (modified tube feet) surrounding the mouth to sweep in food & water
Tentacles have sticky ends to collect plankton
Show bilateral symmetry
Can eject parts of their internal organs (evisceration) to scare predators; regenerate these structures in days

29. 5) Holothuroidea
Bulb-like sacs or ampulla on the upper end of each tube foot contract & create suction to help move, attach, or open bivalves
Rows of tube feet on oral surface (underside) are found in ambulacral grooves under each arm

30. Feeding & Digestion
Tube feet attach to bivalve mollusk shells & create suction to pull valves apart slightly
Starfish everts (turns inside out) its stomach through its mouth & inserts it into prey
Stomach secretes enzymes to partially digest bivalve then stomach withdrawn & digestion completed inside starfish