Echinoderms

Echinoderms

Spiny skin

nephrozoans

- radial symmetry

- tube feet

- internal skeleton (endoskeleton)

- water vascular system

- no cephalization

- 2 sided (oral, aboral)

ex. starfish, sea urchins, sea cucumber, etc

Feeding

Tube feet pry open shells

stomach flip out -> eat animal in own shell

can also be algae scrapers or filter feeders

respiration + internal transport

tin walled tube feet

gas/waste exchange through cell membranes

excretion

feces -> anus (other than brittle stars)

cellulose waste -> ammonia

response

basic nervous system

nerve ring around mouth

light sensitive cells -> eyespots on arms

has statocysts for balance

Movement

tube feet

moveable spines (sea urchins)

flexible arms

sea cucumber - like a worm

Reproduction + regeneration

male or female (distinct sexes) -> testes or ovaries in arms

laevae metamorphose

regeneration - must contain part of the middle