Question

10 points about phylum cnidaria​

Answer 1

Answer:

General characteristics of Phylum Coelenterata

• Kingdom: Animalia
• Habitat: aquatic, mostly marine.
• Habit: solitary or colonial. Each individual is known as zooid.
• Symmetry: radially symmetrical
• Grade of organization: tissue grade of organization.

Answer 2

Answer :

Cnidaria -

• They are aquatic and mostly marine.
• They are sessile or free living.
• They are radially symmetrical animals.
• There is a presence of cnidoblast on cnidocytes on the tentacles of their body.
• These cnidoblast are used to for the defence and capture of their prey.
• They have tissue level of organisation and are diploblastic.
• They have gastrovascular cavity with a single opening.
• The digestion takes place intracellularly and extracellularly.
• Some of the medians like corals have skeletons composed of calcium carbonate.
• Cnidarians exhibit to body forms called polyp and Medusa.
• The polyp form is sessile and is cylindrical in shape like hydra.
• The Medusa form is free living and umbrella shaped.
• They exhibit metagenesis that is existing in both the forms.
• Polyps produce medusae asexually whereas Medusa produce polyps sexually.
• Ex : Physalia, Pennatula, etc.