Unit 4b journal #1 3/27
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:
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?
- 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
What is the seive plate that filters water before it enters the water vascular system?
- What is the seive plate that filters water before it enters the water vascular system?
- Madreporite b. Pyloric caeca c. pedicellaria
- Another name for the pyloric caeca is
- The pinchers on top of the body that are used to free skin of debris are called
- Madreporites b. Pedicellaria c. Tiedeman bodies
- What is responsible for movement, respiration, and circulation.
- Pyloric caeca
- Nervous system
- Water vascular system
- Which side of the starfish is shown?
- Echinoderm- “spiny skin”
- Have water vascular system
- Do not have true circulatory, respiratory, or excretory system
- Pentaradial symmetry- body parts arranged in fives or multiples of fives around an oral (mouth) and aboral (anus) surface.
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.
- 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.
- 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!
- 1. Breathe via
- Tube feet
- Dermal gills- aboral surface
- 2. No blood or circulatory system
- 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
- 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- dioecious
- a. 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
- Ex: sea urchins & sand dollars
- Globe or disc shaped
- No rays
- Movable, hollow
- spines- may be
- venomous 5. Skeleton of 10
- ossicle plates- test
- IIIc. Class Ophiuroidea
- Ex: brittle stars
- Long narrow arms
- Habitat- rocks, coral
- Predators & scavengers
- Use arms & tube feet in
- sweeping motion to collect
- prey which is then transferred to the mouth.
- IIId. Class Holothuroidea
- Ex: sea cucumbers
- No rays
- Elongate body
- Circumoral tentacles
- (surround mouth)
- 5. No spines or pedicellaria
- 6. “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 Crinoidea
- Ex: sea lilies & feather stars
- Usually sessile
- Have fan-like appearance
- Filter feeders
- 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
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