1. Phylum Echinodermata Phylum Hemichordata Phylum Chordata
Clade Deuterostomia
Phylum Echinodermata
Phylum Hemichordata
Phylum Chordata

2. Protostomes vs. Deuterostomes
Zygote cleaves to become blastula and then forms gastrula. The blastopore of the gastrula can become either the mouth or the anus of the organism
Protostome- “first mouth” Blastopore becomes the mouth. Ex-Annelids, Mollusks and arthropods
Deuterostome- “second mouth” Blastopore becomes anus.
Ex-echinoderms, hemichordates,chordates

3. Embryonic Development
Protostome
Blastopore becomes mouth
Deuterostome
Blastopore becomes anus
(Animation)

4. Coelomates- true body cavity lined with mesoderm
EX: all other animals

5. Phylum Echinodermata

6. Phylum Echinodermata Ouch!
Includes starfish, sea urchins, sea cucumber & sand dollars- all marine
Successful for 500 my
“Spiny-skinned”
Pentaradial Symmetry
Coelom, no segmentation
endoskeleton
Lack a centralized brain- have a
Nerve ring with radial and lateral
nerves -sense touch, light, temp,
water conditions
Ouch!

7. Phylum Echinodermata: Anatomy
Bipinnaria larvae(bilaterally symm.)
Water Vascular System:
-- Series of water-filled canals
-- Carries out functions including respiratory,
circulation, and movement.
-- Oxygen, food, & wastes are carried by the
water vascular system.

8. Phylum Echinodermata: Anatomy
Water enters madreporite and flows through the stone canal and then enters the circular ring canal.
Water then is separated into five radial canals that branch into double rows of bulblike structures called ampullae, which are on each side of the ambulacral ridge.
The ampullae are connected to suckerlike
podia = tube foot

9. Water Vascular System

10. Phylum Echinodermata: Anatomy
Have 5 sections or rays or arms
Tube Feet:
-- Act like suction cups
-- Extend from the body
-- Used to “walk”, capture, and hold prey
*How a single tube foot moves*

11. Tube Feet

12. Checkpoint 1. What does Echinodermata mean?
2. What are the basic characteristics of these animals?
3. What type of symmetry do echinoderms have?
4. What are the functions of the water vascular system?
What do echinoderms use to move?
What type of embryological development do they have?

14. Class Asteroidea Star Fish

15. Starfish: External Anatomy
Typically have 5 arms-
rays thick and short
Arms emerge from a central disc
Have an endoskeleton of small calcareous plates called ossicles

16. Starfish: External Anatomy
From the ossicles project spines & tubercles that are responsible for their spiny surface

17. Starfish: External Anatomy
On the oral surface- ventral side w/ mouth
-- Ambulacral (am-bu-la ‘kral) grooves: Radiate out along the arms from the centrally located mouth
-- Tube feet project from the grooves
Ambulacral Groove

18. Starfish: External Anatomy
On the aboral surface- dorsal surface that includes the madreporite and anus.

19. Starfish: Internal Anatomy
Prey on bivalves
Two stomachs
Pyloric stomach- used for digestion
cardiac stomach-can be extended outward to engulf and digest prey.

20. Digestion Starfish push their stomach out once prey is caught.
-- cardiac stomach pushes out of mouth to surround
prey (ex: clam)
-- pyloric cecae-Pours out enzymes
2/arm
-- Digests clam in its own shell
-- Then it pulls its stomach and the partially digested
prey into its mouth. Pyloric stomach completes digestion.

21. Reproduction Asexual reproduction- --Regenerates arms
-- If pulled apart into pieces, each piece will
grow into a new animal, as long as it contains
a portion of the central disc.

22. Reproduction
Sexual- Individual starfish are male or female. Fertilization takes place externally, both male and female releasing their gametes into the environment.
Resulting fertilized embryos form part of the zooplankton and are called deuterostomes.

23. Reproduction
The deuterostomes then become a larva that are bilateral symmetrical.
As they grow, they then change to radial symmetrical adults.

24. 1 - Ambulacral ossicles
and ampullae.
2 - Madreporite.
3 - Stone canal.
4 - Pyloric caecae.
5 - Rectal glands.
6 - Gonads.

26. Class Echinoidea Sea Urchins & Sand Dollars

27. Class Echinoidea Sea Urchin -- Eat algae
-- Have calcium carbonate plates covered with
spines.
-- Can swivel spines
-- Many animals prey on sea urchins
-- Yes, people eat sea urchins
Call it “roe”

28. Sea Urchins
Sea urchins are one of the sea otters favorite food.
Sea otters keep sea urchin populations in check. Without sea otters, the sea urchins can devastate kelp forests which upsets the ecosystem.

29. Sea Urchins
On the oral surface of the sea urchin is a centrally located mouth made up of five united calcium carbonate teeth or jaws, with a fleshy tongue-like structure within.
The entire chewing organ is known as Aristotle's lantern.

30. Sea Urchins
Shell, which is also called the "test", is globular in shape and covered with spines.

31. Sea Urchin
The spines, which in some species are long and sharp, serve to protect the urchin from predators and aid in locomotion.
The spines can inflict a painful wound on a human who steps on one, but they are not seriously dangerous, some are venomous.

33. Sand Dollars

34. Class Echinoidea Sand Dollars -- Flattened disk
-- Few animals eat/bother sand dollars.
-- Burrows into the sand.
-- Also called sea biscuits.

35. Class Holothuroidea Sea Cucumbers

36. Class Holothuroidea Sea Cucumbers: -- Look like warty moving pickles
- - arms or rays absent
- - tentacles around mouth
-- Benthic: Live on the ocean floor

37. Sea Cucumbers Are little bull dozers -- Eat detritus in sand
-- Suck up organic matter & remains of other
organisms.
-- Sea cucumbers extract oxygen from water in a pair of 'respiratory trees' that branch off the cloaca just inside the anus, so that they 'breathe' by drawing water in through the anus and then expelling it.

38. Sea Cucumbers
A variety of fish, most commonly pearl fish, have evolved a Mutualistic symbiotic relationship with sea cucumbers in which the pearl fish will live in sea cucumber's cloaca (anus) using it for protection from predation,
The pearl fish’s waste provides a source of food/nutrients to the sea cucumber

39. Class Holothuroidea More Sea Cucumber
-- When threatened, they spill their guts!
-- It takes 1 ½ to 5 weeks to re-grow their guts
-- The predator will eat the ejected guts, &
leaves the sea cucumber alone. It eventually
grows back the lost organs.
-- Yes, people eat them!

41. The End

42. Checkpoint
1. List the three classes of Echinoderms studied, facts about each class, and the organisms that belong to these classes.