1 / 22

PHYLUM ECHINODERMATA

PHYLUM ECHINODERMATA. General Information 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.

guy
Download Presentation

PHYLUM ECHINODERMATA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PHYLUM ECHINODERMATA

  2. General Information • 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.

  3. Classification • 1. Kingdom Animalia • 2. Phylum Echinodermata • 3a. Class Asteroidea • 3b. Class Echinoidea • 3c. Class Ophiuroidea • 3d. Class Holothuroidea • 3e. Class Crinoidea

  4. IIIa. Class Asteroidea (sea stars) • 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.

  5. Oral (ventral) surface

  6. Aboral (dorsal) surface Central disk Arm/Ray Spine

  7. 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.

  8. Radial canal

  9. 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!

  10. D. Respiration/circulation 1. Tube feet 2. Dermal gills- aboral surface 3. No blood or circulatory system 4. Have vestigial hemal system but function is unknown.

  11. Excretion • 1. Tiedemann’s bodies- (in ring canal) filter water of debris • 2. Amoebocytes- collect debris & bodily wastes & excrete thru dermal gills. • Nervous/sensory system- chemicals & light • 1. Nerve ring around mouth • 2. Radial nerves in each arm (coordinate tube feet) • 3. Photosensitive eyespots at tip of each ray

  12. Reproduction • 1. Asexual- regeneration • a. Can take up to a year • b. Some broken arms can regenerate entire body if central disk is attached

  13. 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

  14. Central disc • Arm/ray • Madreporite • Ambulacral canal • Endoskeletal plates • Ampulla • Coelom • Anus • Cardiac stomach • Pyloric stomich • Pyloric caecum • gonad

  15. IIIb. Class Echinoidea- sea urchins & sand dollars • Globe or disc shaped • No rays • Movable, hollow • spines- may be • venomous • 4. Skeleton of 10 • ossicle plates- test

  16. Digestion- chewing • mouth called aristotles • lantern • Eat algae, coral, • dead animals • 7. Water vascular system, tube feet • 8. Habitat- rocks, sand, mud, shallow water

  17. IIIc. Class Ophiuroidea- 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.

  18. IIId. Class Holothuroidea- sea cucumbers • No rays • Elongate body • Circumoral tentacles • (surround mouth) • 4. No spines or pedicellaria • 5. “earthworms of the sea”- feed on detritus & turn over ocean soil

  19. 6. Digestion- food trapped in net-like tentacles which are “licked” clean by mouth. 7. Evisceration- eject mass of visceral organs when disturbed. Confuses predator.

  20. IIIe. Class Crinoidea- sea lilies & feather stars • Usually sessile • Have fan-like appearance • Filter feeders

More Related