| A | B |
|---|
| Echinodermata | phylum of "spiny skins" |
| chordates | echinoderms may share a common ancestor with lower chordates |
| larval symmetry | free swimming, bilateral symmetrical larva |
| adult symmetry | bottom dwelling, radil symmetrical adults |
| pentaradial symmetry | five radii or multiples of 5 |
| endoskeleton | internal skeleton composed of calcium plates which may include protruding spines |
| water-vascular system | a network of water filled canals |
| tube feet | numerous small, movable protrusions that aid in movement, feeding, respiration, and excretion |
| circulatory system | none in echinoderms |
| respiratory system | none in echinoderms |
| excretory system | none in echinoderms |
| nervous sytem | nerves, but no head nor brain |
| reproduction | two sexes; can reproduce sexually or asexually |
| sessile | not free living, possible status of fossilized echinoderms |
| five classes | crinoidea, asteroidea, ophiuroidea, echinoidea, holothuroidea |
| parthenogenesis | reproduction of organisms without the fusion of gametes of the opposite sexes |
