This document discusses the phylum Echinodermata, which includes sea stars, brittle stars, feather stars, sea cucumbers, and sea urchins. It describes their key characteristics such as radial symmetry, multiple arms radiating from a central disc, and a water vascular system. It provides details on the classes within this phylum, including their anatomy, feeding behaviors, locomotion methods, and examples such as crown-of-thorns starfish.

1. PHYLUM
ECHINODERMATA
Echinoderms: Sea stars, brittle stars, feather stars, sea cucumbers, sea
urchins

2. CHARACTERISTICS
• Radial symmetry
• Several arms (5 or
more, mostly grouped 2 left- 1
middle- 2 right) radiating from
a central body.
• Body consist of equal
segments, each containing a
duplicate of various internal
organs.

3. CHARACTERISTICS
• No brain nor hearts
• With eyespots on each arm
• Mouth situated on the
underside and anus on top
(except feather stars, sea
cucumbers and some urchins).
• Contains tube feet with suction
pads controlled by water
vascular system.

4. CHARACTERISTICS
• Some are carnivorous
while others are detritus
foragers.
• Reproduction is through
release of sperms and egg
into the water.
• Capable of regeneration
and fragmentation.

5. TYPES OF ECHINODERMS
•Class Asteroidea
•Class Ophiurodea
•Class Echinoidea
•Class Holothuroidea
•Class Crinoidea

6. WHAT IS THIS?

7. • Cushion starfish (Culcita nouvaeguineae)

8. CLASS ASTEROIDEA
• Carnivorous and feed on sponges and
molluscs some are specialized
feeders.(crown of thorns)
• Doesn’t have hard mouth parts to help
them capture prey.

9. TRIVIA
• Crown of thorns (Acanthaster planci)
• One of the largest and the most venomous
starfish.
• Size reaches up to 50 cm in diameter.
• 10 to 20 spiny arms with formidable thorn like toxic
spines
• Feed on coral polyps
• Predators: Triton shell and some puffer fish

10. CROWN OF THORNS
(ACANTHASTER PLANCI)

11. CLASS OPHIUROIDEA
• Close relatives of sea stars
• Have five snakelike arms which
are highly flexible.
• No replication of internal
organs, just one set in the central
disk.
• Smaller central disk and no anus.

12. • Arms of brittle stars
are fragile. ( Defense
Mechanism)
• Most active and
fastest moving
echinoderms
• Feed on plankton but
also on detritus.

13. • Serpent Stars
• Coiled snakelike
around branches of
gorgonians.

14. TRIVIA
• Basket stars
• Specialized type of brittle
stars
(Astroglymma sculptum)

15. CLASS ECHINOIDEA
Sea urchins
• External chitinous skeleton
and a centrally located jaw
• Some have speherical bulblike cloaca.
• Movable spines are attached
to the body, some are
venomous

16. • Locomotion by tube feet
but also by movement of
the spines on the underside
of the body.
• Generally nocturnal
• Most are algal grazers but
some feed on sponges and
detritus.

19. CLASS HOLOTHUROIDEA
• Don’t have radial symmetry
but are bilateral.
• Cucumber shaped with
elongated muscular, flexible
body with mouth at one end
anus on the other.
• Tentacles present in the
mouth for food collection

20. • Feed on rich organic film
coating sandy surfaces.
• Crawl over the bottom
and ingest sand.
• Move by means of tube
feet.
• Releases its digestive tract
when threatened (defense
mechanism)

22. PHYLUM CRINOIDEA
• Radial symmetry
• Cup-shaped body
• Numerous feathery arms project from a central
disc.
• Have 5 up to 200 arms (pinnules)
• Nocturnal
• Usually cling to sponges.

23. FEATHER STARS

24. • Source: http://www.starfish.ch/reef/echinoderms.html#starfish