Echinodermata
- Includes sea stars, sea urchins, brittle stars, sea cucumbers, and sand dollars
- Invertebrate- no back bone
- Deuterostome- during embryonic development the first opening, blastopore, forms the anus
- Coelomates- has true coelom- a fluid filled cavity in the body that contains the digestive tract and other organs.
- Bilateral symmetry as an embryo
- Radial symmetry as adults
- Reproduction can be sexual but fertilization is external
- Reproduction can be asexual, fragmentation and regeneration- any portion of the echinoderm that consist of part of the central canal can break off and form another viable organism
- Endoskeleton- calcium plate on the inside of the body
- Spines
- Lack excretory system
- Complete digestive tube
- Simple nervous system
- Ganglia- primitive brain
- Open circulatory system