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QUESTION :
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■ Give General Characteristics of Phylum Echinodermata.
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Answers
Answer:
These are exclusively marine animals.
The larval forms show bilateral symmetry and adult forms show radial symmetry.
They are triploblastic.
It exhibits organ system grade of organisation.
They have a true coelom.
The body is uniquely shaped. It can star like, elongated or spherical.
The body is unsegmented without a head.
The body surface is covered with calcareous spicules.
Body cavity has the distinguishing water vascular system.
Tube feet help in locomotion.
The brain is absent but a nervous system is present with a nerve ring and radial nerve cords.
Respiration occurs through tube feet and gills.
Sense organs are poorly developed and include tactile organs, chemoreceptors, terminal tentacles etc.
Sexes are separate.
Fertilisation is external.
Lost parts can be regenerated.