Question

3. write important characteristic of phylum which has example asterias having sping skin.

Answer 1

It is phylum Echinodermata which has Star fish ( Asterias)

1.It has calcareous ossicles as the endoskeleton,hence the name spiny bodied animals.

2.All are exclusively marine.

3.Have a complete digestive system with mouth on lower(ventral) surface and anus on upper surface(dorsal).

4.Presence of Water Vascular System is their most distinctive feature which helps in:

• locomotion
• Transport & capture of food
• Respiration

5.Excretory System is absent.

6.Sexes are separate & reproduction is sexual with indirect development( i.e free swimming larva is formed).

7.Adults have pentamerous radial symmetry while larvae are bilaterally symmetrical.