Question | Answer |
How many tissue layers do echinoderms have? | Triploblastic |
Are echinoderms segmented or unsegmented? | Segmented |
How does the mesoderm line the echinoderms body wall? | Eucleomate |
What type of body symmetry do echinoderms have? | Secondary pentamerous radial symmetry.* Bilateral as larvae radial as adults. |
What is the structure of an echinoderms skeleton? | * endoskeleton with spines through skin. Plates of calcium carbonate. |
What type of vascular system do echinoderms have? | * water vascular system |
What is Echinoderm Taxonomy based on? | Deviations from ancestral body plan |
What is the most primitive class of echinoderms? | Crinodia- sea lily's and feather stars with tube feet and spines
prominent arms |
Class ophiudroia | Basket stars and brittle stars- mouth on the underside of body disk. Prominent arms |
Class Asteroida | Starfish
Prominent arms |
What is the class with deviations from the ancestral body plan without arms called? | Concentracycloida- Sea Dasies |
What is the structure of the echinoderms digestive system? | 2 ring canals. Some have an incomplete digestive system. |
Sand Dollar | Has shortest oral to aboral surface |
Sea Biscut | Mid length oral to aboral surface |
Sea urchen | Long oral to aboral surface |