Echinoderms

(Sea Stars, Sea Urchins,

Sand Dollars, Sea

Cucumbers)

General Stuff

• Echinoderms belong to the Phylum

Echinodermata, meaning “hedgehog

skin”.

• Echinoderms have spiny skins.

• They have radial symmetry.

• They lack body segmentation.

• There are more than 5000 species of

Echinoderms.

• Types are sea stars, sea urchins, sea

cucumbers, sand dollars.

Digestive System

Digestive system is perfect . Digestive system starts

from the mouth of the position under the surface of

the body. Then passed through the pharynx, the

esophagus, the stomach, then into the intestines, and

the last in the anus. The anus is located on the upper

surface of the body and does not function on some

Echinodermata. In the stomach of this animal has five

branches, each branch leading to the arm. In each

arm of this forked stomach, but it ends nowhere.

Respiratory System and

Excretion

Echinodermata breathe using lungs skin or dermal

branchiae (Papulae) the protrusion of the wall of the

body cavity (coelomic) is thin. These protrusions are

protected by the cilia and pediselaria. In part this is

an exchange of oxygen and carbon dioxide. There

are also several types of Echinodermata that

breathes with the tube feet. The remains of

metabolism that occurs in the cells of the body will be

transported by amoebacyte (amoeboid cells) to the

dermal branchiae henceforth be released to the

outside of the body.

Reproductive system

Echinoderms have separate sexes, so there

are male and female. Fertilization occurs

outside the body, that is, in sea water. The

fertilized egg will divide rapidly generate

blastula, and later developed into a gastrula.

This gastrula develop into larvae. Larvae also

called bilateral symmetry bipinnaria shaped.

These larvae swim freely in the water looking

for a suitable place to be branchidaria, then

undergo metamorphosis and eventually

become adults

Types of Echinoderms

Sea Stars- Starfish• Have radial symmetry.

• Most starfish have 5 “arms”or rays.

• Starfish have tube feet for locomotion, and strong suction to hold them in place.

• They also have a water vascular system that enables them to store water in their tube feet so they can survive while the tide is out.

• They breathe through small gills in their skin.

• Their mouths are located on the underside of their bodies.

• Starfish can regenerate. (must have the central disc attached).

More Starfish Stuff

• Sea Stars are carnivorous, yup, they eat

mostly shellfish, snails, and barnacles.

• They use their tube feet to pry open the

shells and then throw their own stomachs

out into the shell to digest the meat before

it’s brought back into its body!

• There are lots of different types of Sea

Stars, about 2000 different kinds.

• Most Sea Stars have spiny skin.

Sea Star Anatomy

Sea Urchins• Sea Urchins look like big pin cushions.

• They use these spines for protection against predators.

• The spines also act like stilts to keep their bodies up off the ground so the tube feet can pull them around!

• They eat mostly algae.

• They live mostly attached to rocky crevices, which protect them from waves and tide surges.

• They have become a popular item to eat and are being harvested in alarming numbers.

Sea Urchin Anatomy

Sand Dollars

• Are found on the sandy shore or muddy bottoms.

• They feed standing on edge with their tube feet acting as filters.

• The star pattern seen on top of the sand dollars is actually caused by special breathing tube feet!

• The mouth is found on the under side of the animal.

Sand Dollar Anatomy

Sea Cucumbers• Sea cucumbers have tentacles at their

mouth openings to grab and hold food.

• They look like snails, but have radial symmetry and spiny bodies like all other echinoderms.

• When provoked, or annoyed, Sea cucumbers throw out their intestines to entangle, frighten, or confuse their predator! Then the intestines are regenerated.They are filter feeders and have a sticky slime that covers their tentacles and lets them grab particles from the ocean floor.

• Sea Cucumbers are considered a delicacy in Asian cultures.

Interesting Stuff

• Some Sea cucumbers are quite

poisonous, and the poison has been used

as an inhibitor of Cancer growth.

• Sea Cucumbers secrete a sticky glue as a

defense mechanism that has been used as

a bandage to bind wounds.

• Sea Cucumbers will stick each tentacle in

their mouths, lick them off and then do the

same with the next one- kind of like you

licking your fingers after eating!

Sea Cucumber Anatomy

Questions...• What is the meaning of Spiny skins?(by : naila zulva /22)

• What is the roles of Echinoderms?(by : nur hidayatun /23)

• How the reproduction of Echinoderms?(by : anang nazaruddin /01)

Answer• Spiny skins is the skin that has lot of

spine,and it is made by lime

• The roles of echinoderms are can be used for food source,cracker mixture,and as a cleaner from organic waste.

Continue• The reproduction of echinoderms is fertilized egg

will divide rapidly generate blastula, and later

developed into a gastrula. This gastrula develop

into larvae. Larvae also called bilateral symmetry

bipinnaria shaped. These larvae swim freely in

the water looking for a suitable place to be

branchidaria, then undergo metamorphosis and

eventually become adults