Enchinoderms, Echinodermata

1. PHYLUM
ECHINODERMATA
RAQUEDAN, RODEBELLE P.

2. PHYLUM ECHINODERMATA
“SPINY SKIN”
OVER 6000 MARINE SPECIES

3. ECHINODERMATA
“dermos” =ski“echinos” = spiny
Vernacular names: Echinoderms, ‘Spiny-
Skinned”Examples
:
1. Sea Star
2. Brittle
star3. Sea Urchin
and sand
dollar4. Sea Lilies
and feather
Star5. Sea
Cucumber

4.  Animalia
 exclusively marine
 organ system grade
 Triploblastic
 Adults are radially symmetrical while the larvae are
bilaterally symmetrical.
 Coelom: present ( coelomate)
 Body without segmentation
 The shape of the body is flat, star like, spherical or
elongated.
 Head is absent
 Presence of tube feet
 Presence of water vascular system
 Mouth is present on ventral side while anus is present
on dorsal side
General Characteristics

5. Characteristics
 Respiration: by papule, gills or cloaca respiratory tree
 Nervous system: absent, they are brainless organism.
 Circulatory system: is reduced, heart is absent
 Blood has no pigment.
 Digestive system: complete
 Excretory system: absent
 Sexes: mostly dioecious, rarely monocious
Reproduction:
Sexual: by gamatic fusion
Asexual: regeneration
 Fertilization: external
 Development: indirect with characteristic larvae

6.  larval forms show bilateral symmetry
and adult forms show radial symmetry
Free moving and radial symmetry
Pentaradial Symmetry – body
radially symmetrical in 5 parts or
multiples of 5
Echinodermata Symmetry
body parts repeat
around the center
of the body.
1. No front or
back
2. Do have a
top (dorsal) and
bottom (ventral).

7. Echinodermata
a. Internal skeleton made of stiff plates of
calcium carbonate, called ossicles,
which are found on the skin of the echinoderm.
b. Network of tubes & appendages

8. NERVOUS SYSTEM
• ECHINODERMS HAVE A DIFFUSE NERVOUS SYSTEM WITH NO
“BRAIN”
• NERVE RING THAT ENCIRCLES THE MOUTH
• RADIAL NERVES THAT EXTEND TO EACH ARM
• COORDINATE THE FUNCTIONS OF TUBE FEET
• NERVE NET THAT COORDINATES THE FUNCTION OF THE BODY
WALL

9.  The ability to grow lost or damaged body
parts
Some times a severed arm can grow into a
new organism if 1/5 of the central disc is
present
Regeneration/Autotomy

10. b. Water Vascular System
 Network of fluid filled canals that transport water
throughout the echinoderms body
 Connected to tube feet
Used for:
1. feeding
2. movement
3. respiration
4. excretion

12. Ring canal – ring in the
center of the sea stars
body that attaches to the
radial canals.
Radial Canal –
extends from the
ring canal to the end
of each arm which
carries water to
hundreds of tube
feet.

14. 5 Classes of Echinoderms
1.Class Asteroidea
2.Class Ophiuroidea
3.Class Echinoidea
4.Class Holothuroidea
5.Class Crinoidea

15.  They are commonly known
as starfish or sea stars.
 They have a flattened, star-shaped
body with five arms.
 They have tube feet with suckers.
 They respire through papulae.
 The body comprises of calcareous
plates and movable spines.
 Pedicellaria is present.
Class Asteroidea

19.  commonly known as Brittle stars or ophiuroids or
serpent stars.
The body is flat with pentamerous discs.
The tube feet are devoid of suckers.
They respire through Bursae.
The long arms are demarcated from the central disc.
Ophiuroidea

20. Class Echinoidea
The body is hemispherical.
The tube feet contains suckers.
The body does not have arms.
The body has a compact skeleton and movable
spines.
Plates:
10 plates; Alternating ambulacral (have openings for
tube feet) and
Interambulacral (bumps for spines)

21. Class Holothuroidea
Sea cucumbers
The body is long and cylindrical.
The arms, spines, and pedicellariae are absent.
They respire through the cloacal respiratory tree.
They possess tube feet with suckers.

22. Feather stars and Sea lilies
The body is star-shaped.
The tube feet have no suckers.
The arms are bifurcated.
Spines and pedicellariae are absent.
Class Crinoidea

23. Ecosystem Impact
 keystone species
Economic Importance for Humans: Positive
 A contribution to the overall knowledge of
animal fertilization and development.
 easy to culture and maintain in a lab setting,
and produce a large amount of eggs.
 Sea urchin eggs are also edible and often
served in sushi bars. (Brusca and Brusca,
2003; University of Alabama Center for
Communication and Educational Technology,
2000)
Positive Impacts
 food

24. Why Sea Stars are dying?

25. A Video about Echinoderms