what are the 5 classes in this phylum?
describe the phylum echinodermata
- ‘spiny skinned’ animals
- secondarily radially symmetrical
- tube feet
- water vascular system that operates podia
what are in the class Holothuroidea and describe them?
- fleshy body with tentacles surrounding the mouth
what are in the class Crinoidea and describe them?
sea lilies (stalked) and feather stars (have lost stalks) - flower like and mouth at the top
what are in the class Echinoidea and describe them?
- fused ossicles
- show a degree of bilateral symmetry
what are in the class Ophiuroidea and describe them?
star shaped with 5 arms and a central disc
what are in the class Asteroidea and describe them?
star shaped - central disc not as obvious as brittle stars
- some have long arms some short
- some have > 5 arms