1. Echinoderms and Invertebrate Chordates

2. Echinoderms Members of the phylum Echinodermata
Sea Stars, Sea Urchins, Sea Cucumbers and Sea Lilies

7. Pineapple Sea Star

8. Brittle Star

9. Crown of Thorns

10. Sea Urchin

11. Feather Star

12. Feather Stars

13. Echinoderm Characteristics
All Echinoderms have a hard, spiny or bumpy endoskeleton composed of calcium carbonate which is covered by a thin epidermis

19. Rays
Long, tapering arms of a sea star which are covered with short rounded spines

25. Pedicellariae
Spines of some sea stars and sea urchins have become modified into pincer like appendages
Used for protection and for cleaning the surface of its body

26. Radial Symmetry
Is an advantage to animals that are stationary or move slowly
Enables animals to sense potential food, predators and other aspects of their environments
Is a circular body plan

28. Basket Star

29. Sea Lily

30. Water Vascular System
Enables Echinoderms to move, exchange gases, capture food and excrete wastes
Is a hydraulic system that operates under water pressure

31. Madreporite
A sieve like, disk shaped opening on the upper surface of the echinoderm’s body
Water enters and leaves the water vascular system through this opening

34. Tube Feet Hollow, thin walled tubes that end in a suction cup
Look somewhat like miniature droppers
Each tube foot works independently of the others

38. Ampulla
Round muscular structure which works something like the bulb of a dropper located at the base of the tube feet

39. Nutrition
Sea stars are carnivorous and prey on worms or on mollusks such as clams
Most sea urchins are herbivores and graze on algae
Brittle stars, sea lilies and sea cucumbers feed on dead and decaying matter that drifts down to the ocean floor

41. Sea Star Digestion
To eat, a sea star pushes it stomach out of its mouth, releases powerful enzymes which turn solid food into a soupy liquid that the stomach can easily absorb

42. Nervous System
Echinoderms have no head or brain, but they do have a central nerve ring that surrounds the mouth
Nerves extend from the nerve ring down each ray
Each radial nerve then branches into a nerve net that provides sensory information to the animal

43. Senses
Echinoderms have cells that detect light and touch, but most do not have sensory organs
Sea stars are an exception-at the tip of each ray on the underside is an eye spot which consists of a cluster of light detecting cells

46. Larvae Have bilateral symmetry, a feature more common to chordates
Ciliated larvae develop from the fertilized egg of en echinoderm then becomes a mature adult through dramatic changes known as metamorphosis

50. Diversity of Echinoderms
Approximately 6000 species exist today
Four classes
Ophiuroidea-brittle stars
Echinoidea-sea urchins and sand dollars
Holothuroidea-sea cucumbers
Crinoidea-sea lilies and feather stars

51. Sea Stars Most species have five rays, but some have up to 40
Rays are tapered and extend from the central disk

77. Brittle Stars
Extremely fragile, parts of its rays will break off, an adaptation that helps it survive when attacked by a predator
Do not use tube feet for locomotion, propel themselves with a snakelike, slithering motion
Tube feet pass particles of food to the mouth

84. Sea Urchins Globe or disk shaped animals covered with spines
Do not have rays
Look like living pin cushions, spines protect them from predators

94. Sand Dollars
Sand dollars have a flat, circular skeleton with a five petaled flower pattern on the surface
A living sand dollar is covered with small, hair like appendages
Tube feet on the top are modified into gills, those on bottom aid in bringing food particles to the mouth

97. Sea Cucumbers Vegetable like appearance
Have a leathery covering which allows them to be more flexible than other echinoderms
Use tentacles and tube feet to pull themselves along the ocean floor
May expel a tangles mass of sticky tubes or rupture releasing some internal organs when threatened

99. Sea Cucumber

119. Sea Lilies Are sessile-cannot move around
Body is on a stalk attached to the ocean floor
Are filter feeders

125. Feather Stars Larvae are sessile
Adult feather star uses its feathery arms to swim from place to place

137. Chordates Includes 3 subphyla
Urochordata-sea squirts
Cephalochordata-lancelets
Vertebrata-the vertebrates
Have a notochord-a dorsal hollow nerve cord

139. Invertebrate Chordates
Have no backbone, gill slits, and muscle blocks
Bilateral symmetry
All chordate embryos have a notochord

141. Notochord
A long semirigid, rodlike structure located between the digestive system and the dorsal hollow nerve cord
Made up of large, fluid-filled cells held within stiff fibrous tissues in invertebrate chordates

142. Notochord

143. Dorsal Hollow Nerve Cord
Develops from a plate of ectoderm that rolls into a hollow tube
Composed of cells surrounding a fluid-filled canal that lies above the notochord
Cells in the posterior portion become the spinal cord, the anterior portion develops into a brain

144. Gill Slits Paired openings located in the pharynx, behind the mouth
Many chordates have several pairs of gill slits
Used by some to strain food from the water and for gas exchange during respiration

145. Muscle Blocks
Modified body segments that consist of stacked muscle layers
Are anchored by the notochord which gives the muscles a firm structure to pull against
Aid in movement of the tail

146. Tunicates Members of the subphyllum Urochordata
Have many of the shared characteristics of chordates during their larval stage

154. Tunicates Also known as sea squirts
Larvae do not feed and are free swimming for only a few days after hatching
The then settle and attach themselves with a sucker to boats, rocks and the ocean floor

155. Incurrent siphon ▼
Pharynx-lined
With gill slits ►
◄ Ciliated groove
Excurrent siphon►
◄Heart
◄Stomach
◄Tunic

173. Lancelets Cephalochordata
Small streamlined and common marine animals about 5 cm long
Bury themselves in the sand with only their heads sticking out
Filter feeders