biologi~

1. Phylum Echinodermata
Introduction

2. • About 6000 species, all marine
Echinodermata

3. • secondary
pentamerous radial
symmetry
internal skeleton
• water vascular
system
Echinodermata
Major characteristics

4. Water Vascular System
• Madreporite
• stone canal
• ring canal
• radial canal
• lateral canals
• Ampulae
• tube feet

5. CLASSIFICATION OF
ECHINODERMATA
• Class Asteroidea
• Class Ophiuroidea
• Class Echinoidea
• Class Holothuroidea
• Class Crinoidea

6. Class Asteroidea
True Starfishes

7. Class Asteroidea
True Starfishes• arms not sharply
delineated from
central disc
• tube feet with
suckers; used for
– Locomotion
– obtaining food
• madreporite and
anus aborally
located
• some have
pedicellariae -
jawlike appendages
of epidermis

8. • Feeding
– Mouth
– cardiac stomach-
can be extruded
– pyloric stomach
– pyloric caecae
– Anus
– feed primarily on
sessile organisms
Class Asteroidea
True Starfishes

9. • Circulation
– poorly developed with fluid filled chambers;
– no heart;
coelom ciliated for fluid movement
• Excretion
– no special organs
– general diffusion across body surfaces like tube feet
• Respiration
– no special organs
– across body membranes
• Nervous System
– associated with epidermis
– circular oral nerve ring with branches into arms
Class Asteroidea
Systems

10. • Epidermis- outer surface; includes
– mucous cells
– epithelium
– Pedicellariae- jawlike appendages of the epidermis
• can open and close
• used to clean body of debris or put debris on body
• Dermis- includes
– nerve cells
– connective tissue
• Skeleton- below dermis
– made of ossicles
– lattice like connections
– Calcium carbonate
– with spines and tubercles
• Muscle layer- below dermis
• Peritoneum that lines coelom
Asteroidea
Body wall

11. • are dioecious;
external
fertilization
• usually 10 gonads;
2 in each arm
• have fissiparity-
division of central
disc into two
animals
Asteroidea Reproduction

12. • free living larvae
• bipinnaria- first
larval form develops
into
• brachiolaria - shows
development of arms
Asteroidea Reproduction

13. Class Ophiuroidea
Brittle Starfishes

14. • 5 arms
usually
• central disc
well marked
off, no
branches of
gut in arms
Class Ophiuroidea
Brittle Starfishes and Basket Stars

15. • no anus, no
ambulacral groove
• madreporite on oral
surface
• no suckers on tube
feet, no ampullae
(have a valve to
control pressure)
• no pedicellariae
• able to move quickly
and snake like hence
their class name
Class Ophiuroidea
Brittle Starfishes and Basket Stars

16. Class Echinoidea
sea urchins, sea bisquits, sand dollars

17. • no arms
• skeleton is
fused into a
solid test
• tube feet have
suckers
• covered with
moveable
spines and
pedicellariae
Class Echinoidea

18. Class Echinoidea
specialized mouth structures - Aristotle's
Lantern

19. Class Holothuroidea
Sea cucumbers

20. • body elongated
in oral-aboral
axis
• skeletal system
reduced or
absent
• no spines or
pedicellariae
• mouth and anus
at opposite ends
of body
Class Holothuroidea
Sea cucumbers

21. • no external
madreporite
• tube feet with suckers
• respiration through
anal respiratory tree
• dioecious; single gonad
• suspension or detritus
feeders
• commensal
relationship with pearl
fish
Class Holothuroidea
Sea cucumbers

22. Class Crinoidea
Sea Lillies

23. • most are extinct
• most primative
• all sessile, with
stalk that
attaches to
substrate
• have branched
arms for filter
feeding
• no suckers on
tube feet
• no madreporite
• no pedicellariae
Class Crinoidea
Sea Lillies