Unit 4B Journal #1 3/27

• Trace the path of water through the water vascular system.

• What would happen to a starfish that had a mutation that caused the stone canal to be deformed?

Unit 4B Journal #1 10/23

• What do these animals have in common?

Unit 4B 3/26

• Please turn in your mollusk essay with rubric and pick up:– Purple echinoderm unit sheet– Echinoderm study guide– Sea star structure/function activity

Unit 4B Journal #2 3/30

• Starfish eat oysters. Oyster farmers use to scuba dive down and cut up the starfish to kill them. Explain why this was NOT an effective method to kill the starfish.

Journal: What do all of these

organisms have in

common?

Phylum Echino-dermata

Journal• Get an iRespond remote and complete Journal.• Use these words in a sentence related to one of the animals

we’ve discussed this school year. Can you combine some of these so you don’t have to write 5 separate sentences?– Germane- relevant– Ignominious- shameful– Imminent- dangerous, close at hand– Factious- turbulent

1. What is the seive plate that filters water before it enters the water vascular system?

a. Madreporite b. Pyloric caeca c. pedicellaria2. Another name for the pyloric caeca is

a. Intestineb. Anusc. gonad

3. The pinchers on top of the body that are used to free skin of debris are called

a. Madreporites b. Pedicellaria c. Tiedeman bodies4. What is responsible for movement, respiration, and

circulation.a. Pyloric caecab. Nervous systemc. Water vascular system

5. Which side of the starfish is shown?a. Oral b. aboral

General Information1. Echinoderm- “spiny skin”

2. Have water vascular system

3. Do not have true circulatory, respiratory, or excretory system

4. Pentaradial symmetry- body parts arranged in fives or multiples of fives around an oral (mouth) and aboral (anus) surface.

Classification

1. Kingdom Animalia

2. Phylum Echinodermata

3a. Class Asteroidea

3b. Class Echinoidea

3c. Class Ophiuroidea

3d. Class Holothuroidea

3e. Class Crinoidea

IIIa. Class Asteroidea (sea stars)

A. Structure/Support

1. Endoskeleton-

a. calcium carbonate plates called ossicles.

b. Spines- deter predators

2. Pedicellaria- pinchers for protection & for keeping aboral surface clean of debris.

A. Structure/Support

3. Central disk- center part of starfish

4. Ambulacral groove- groove thru which tube feet stick out

Oral (ventral) surface

Central disk

Aboral (dorsal) surface

Arm/Ray

Spine

B. Water Vascular System- movement, respiration, circulation, some excretion

1. Madreporite on aboral surface.

2. Stone canal

3. Ring canal

4. Ring canal has Polian vesicles attached that allow for storage of water.

5. 5 radial canals, one in each ray.

6. Water enters hundreds of bubble-like sacs called the ampulla which inflate.

7. Muscles are stimulated which contract ampulla and push water down a tube to the suction cup-like tube foot.

8. The tube foot attaches to a surface creating movement.

c. Digestion/Feeding

1. Mouth is on oral surface (underneath)

2. Use rays & tube feet to grasp prey (clams)

3. Opens shell 0.1mm, enuf to insert cardiac stomach.

4. The pyloric caeca (digestive glands) release digestive enzymes that begin to dissolve prey.

5. As the digestive enzymes work, the clam muscles weaken, making it easier to open.

6. Partially digested food is taken to the pyloric stomach where it is absorbed and nutrients are passed to the pyloric caeca which transport nutrients throughout.

7. Wastes leave thru the aboral surface thru anus.

8. This process can take up to 8 hours depending on size of clam!

D. Respiration/circulation

1. Breathe via

a. Tube feet

b. Dermal gills- aboral surface

2. No blood or circulatory system

Excretion

1. Tiedemann’s bodies- (in ring canal) filter water of debris

2. Amoebocytes- collect debris & bodily wastes & excrete thru dermal gills.

F. Nervous/sensory system-

1. Nerve ring around mouth

2. Radial nerves in each arm (coordinate tube feet)

3. Photosensitive eyespots at tip of each ray

G.Reproduction

1. Asexual- regeneration

a. Can take up to a year

b. Some broken arms can regenerate entire body if central disk is attached

2. Sexual- dioeciousa. Gonads (ovaries-red, testes- white) in each ray

b. External fertilization

c. Gametes released thru gonopore at base of each arm

d. Release pheromones to induce gamete release among other starfish in area for spawning.

e. Larvae (bipinnaria) live amongst plankton until adult organs grow

IIIb. Class Echinoidea

1.Ex: sea urchins & sand dollars2.Globe or disc shaped3.No rays4.Movable, hollow

spines- may be venomous 5. Skeleton of 10

ossicle plates- test

6. Digestion- chewing mouth called aristotles lantern

7. Eat algae, coral, dead animals

8. Water vascular system, tube feet

9. Habitat- rocks, sand, mud, shallow water

IIIc. Class Ophiuroidea1.Ex: brittle stars2.Long narrow arms3.Habitat- rocks, coral4.Predators & scavengers5.Use arms & tube feet in

sweeping motion to collect prey which is then transferred to the mouth.

IIId. Class Holothuroidea1.Ex: sea cucumbers2.No rays3.Elongate body4.Circumoral tentacles

(surround mouth)5. No spines or pedicellaria6. “earthworms of the sea”- feed on

detritus & turn over ocean soil

7. Digestion- food trapped in net-like tentacles which are “licked” clean by mouth.

8. Evisceration- eject mass of visceral organs when disturbed. Confuses predator.

IIIe. Class Crinoidea1.Ex: sea lilies & feather stars2.Usually sessile3.Have fan-like appearance4.Filter feeders

Environmental/Economical Significance

• Sea urchin spines are poisonous if stepped on.

• Sea urchin gonads are a delicacy in Asia.• Sea cucumbers are dried & eaten• Sea cucumber toxin used to kill tumor

cells (may fight cancer)• Starfish are pests in oyster beds• Echinoderm carbonate skeletons can be

ground up and used as lime to enrich soil• Source of food for many organisms in

food web• Decorations