1. “The spiny skinned animals”
Phylum Echinodermata
“The spiny skinned animals”

2. Echinoderm Facts
Hard, spiny, bumpy endoskeleton made of calcium carbonate covered w/a thin epidermis.
As adults, echinoderms have radial symmetry with branching arms called rays.
As larva, echinoderms have bilateral symmetry.
Echinoderms have no head or brain, but they do have a central nerve ring that surrounds the mouth.
Water vascular system (WVS) is a hydraulic system that operates under water pressure used for movement.

3. Echinoderm facts
The water vascular system’s opening is called a madreporite. It opens into a ring canal. The ring canal then goes out to the arms in radial canals. The radial canals then feed water to the tube feet.
Each arm contains two rows of tube feet

4. Echinoderm facts
Tube feet are used in movement, gas exchange and excretion; nitrogen waste excreted as ammonia exits the anus.
At the top of each tube foot is the ampulla which acts like a bulb on a medicine dropper.
Echinoderms are considered to carnivores, herbivores and detritus feeders.
Simple nervous system for most echinoderms – Starfish have up to 200 light sensitive cells clustered in eyespots of each arm. No actual eyes.
Pedicellariae are pincher-like appendages used for protection and for cleaning the surface of the body.
For balance & hearing, statocysts or tiny stones pass over hairs to tell the starfish up from down and sense motion or sound by vibrations in the water.

5. Echinoderm Reproduction
Echinoderms can reproduce sexually or asexually.
Reproduction – echinoderms are either male or female. Sperm and eggs produced in the testes or ovaries is released into the water to become fertilized. This is sexual reproduction.
Reproduction – ask a Fisherman and he will tell you that tearing starfish into chunks is a great way to increase their population. Each chunk will undergo regeneration (asexual reproduction) and form new starfish. So, ripping them up is not a great way to reduce predation on shellfish, which bring in a pretty-penny.

6. Echinoderms The spiny skinned animals include these Classes:
Class Asteroidea - starfish (sea stars)
Class Crinoidea - the crinoids or “feather stars”
Class Ophiuroidea - brittle stars, basket star
Class Echinodermata - sea urchin, sand dollar
Class Holothuroidea - sea cucumbers
6. Class Concentricycloidea – sea daises

7. Class Asteroidea Includes ¼ of the echinoderms Sea stars or starfish
Sea stars typically have 5 arms but can have up to 40.
The mouth is located on the oral or bottom side.
The anus is located on the aboral or top side.

8. Starfish arm
Each arm or ray contains a digestive glands, a radial canal and gonads.
Each arm also contains two rows of tube feet.
Arm will regenerate if torn off = Asexual Reproduction.
Starfish are carnivores that eat clams, mussels, and other bivalves.

10. Section 29.1 Summary – pages 763-769
Sea stars
Pedicellariae
Endoskeleton
Ray
Madreporite
Anus
Ring canal
Nerve ring
Radial canal
Stomach
Radial nerve
Ampullae
Mouth
Digestive gland
Tube feet
Reproductive organ
Eyespots
Endoskeletal plates
Section 29.1 Summary – pages

11. Class Crinoidea Sea lilies & feather stars Filter feeders
some are sessile
some are motile
Their bodies are often found in limestone deposits

14. Class Ophiuroidea Brittle stars & Basket Stars
These are perhaps the fastest of the echinoderms. Do not use tube feet for movement.
Most of them are filter feeders or detritus eaters
Flexible arms, and may be offered as food to get away from predators

15. Basket Star

16. Brittle Star

17. Class Echinoidea Sea Urchins & sand dollars Lack arms or rays
eat algae or are detritus eaters
usually have spines
Gonads prized for sushi
Endoskeleton called a test.

20. Class Holothuroidea Sea cucumbers
Detritus eaters – the vacuum cleaners of the sea
do not have skeletal parts
will eviscerate if they are scared, meaning offer up internal organs as food to distract predator

22. Class Concentricycloidea
Sea daises
Discovered off the coast of New Zealand.
Flattened disc bodies less that 1 cm in diameter.
Three known species to date.

23. Phylum Chordata Three subphyla Phylum Urochordata - tunicates
Phylum Cephalochordata - lancelets
Phylum Vertebrata - vertebrates

24. Invertebrate Chordates
This group belongs to the Phylum Chordata because they contain a stiff but flexible rod called a notochord.
Characteristics
dorsal nerve chord - hollow tube
pharyngeal pouches - out pockets in pharynx
postanal tail - used for propulsion

25. Subphylum Cephalochordata
Lancelets-retain all characteristics throughout its life.
Like to burrow in shallow water sand.
Usually about 5 cm long.
Filter feeders

26. Subphylum Urochordata
Tunicates - AKA “Sea squirts” because their bodies are covered with a tough covering like tunic.
Filter feeds as adults w/incurrent siphons
External fertilization - hermaphrodites that release sperm through excurrent siphons.