Phylum Echinodermata

Question 1

Definition of Echinoderms

Number of species

Answer 1

They are echinoderms and they are slow-moving or sessile marine animals with radial symmetry.

Consists of about 6,000 living species

Question 2

Classes Of Echinodermata

Answer 2

1. Asteroidea: Sea Stars
2. Ophiuroidea: Bristle Stars & Basket Stars
3. Echinoidea: Sea Urchins & Sand dollars
4. Crinoidea: Sea lilies & Feather Stars
5. Holothuroidea: Sea Cucumbers
6. Concentricyloidea: Sea daises

Question 3

Characteristics Of Echinoderms

In terms of skeleton type
In terms of species
In terms of gamete formation and movement
In terms of species’ habitation
In terms of regeneration

Answer 3

They have an endoskeleton made of calcareous or bony plates called Ossicles
Most species are dioecious but few species are hermaphroditic
Individuals release their gametes into the sea water.
No specie lives on land or in fresh water, they are totally marine.
They have a remarkable power of autonomy (Self amputation) and power of regeneration of lost body parts

Question 3

Characteristics Of Echinoderms

In terms of germ layers & skin type
In terms of body symmetry (in adult stage)
In terms of body symmetry (in larva stage)
In terms of symmetrical distinction among radial animals
In terms of body segmentation
In terms of coelom

Answer 3

They are triploblastic animals with spiny skin
Their bodies are radially symmetrical at adult stage
Their bodies are bilaterally symmetrical at larvae stage
They are penta-radially symmetrical
They do not have a segmented body; neither head nor brain
The coelom is well developed and large

Question 4

Unique to Echinoderms is …. ending in …. that function in….

Distinguishing Characteristics Of Phylum Echinodermata

Answer 4

Unique to Echinoderms is the Water Vascular System ending to tube feet that function in: Locomotion, Feeding & Exchange Of Gas

Distinguishing Characteristics Of Phylum Echinodermata: Radial Symmetry, Internal Skeleton and Water Vascular System

Question 5

Ossicles are bound together by … & …
Extending out of ossicles are …, therefore Echinoderms are covered by ….

Answer 5

Ossicles are bound together by muscle & connective tissues
Extending out of ossicles are spines, therefore Echinoderms are covered by calcareous spine.

Question 6

The Water Vascular System has a …. and …. running out into ….
Each tube foot is connected to the … and also to a ….
The muscular … works like a …., forcing …. into the …, causing it to …. and ….

The directional pathway of water movement in the W.V.S:

Answer 6

The Water Vascular System has a central ring canal and connecting tubes running out into each ray.
Each tube foot is connected to the radial canal and also to a balloon-like ampulla
The muscular ampulla works like a squeeze bulb, forcing water into the tube foot, causing it to straighten and extend.

The directional pathway of water movement in the W.V.S:
Madreporite-> Stone Canal-> Ring Canal-> Radial Canal-> Ampullae-> Tube feet

Question 7

Economic Importance Of Echinoderms

In terms of research studies
In terms of oyster industry
In terms of fertilizer
In terms of food

Answer 7

1. Echinoderms eggs are used extensively in research studies dealing with embryology
2. Starfish are very destructive of oyster beds, therefore they are very harmful to oyster industry
3. Dried skeleton of echinoderms are used as a fertilizer because of their high calcium and nitrogen content.
4. In the orient, Sea Cucumbers are dried in the sun and used in soup.