Characterized by radial symmetrySeveral arms radiating from a central
bodybody consists of five equal segments,
each containing a duplicate set of various internal organs
no heart, brain, or eyesmouth is situated on the underside
and their anus on topdo not possess an external skeleton.
a thin outermost skin covers a mesodermal endoskeleton made of tiny calcified plates and spines
Echinoderms are exclusively marine
Occur in various habitats intertidal zones, the
bottom of the deep sea trenches, coral reefs, cold and tropical seas
Some are carnivorous, others are detritus foragers, or planktonic feeders
Reproduction is carried out by the release of sperm and eggs into the waterMost species produce
pelagic (free floating) planktonic larvae which feed on plankton
Echinoderms are important both biologically and geologicallyfew other groupings are so
abundant in the biotic desert of the deep sea, as well as the shallower oceans
their ossified skeletons are major contributors to many limestone formations, and can provide valuable clues as to the geological environment.
Sea Starstypically have five "arms" which radiate from
a central diskusually hunt for shelled animals such as
oysters and clamshave two stomachs, one for digestion, and
one can be extended outward to engulf and digest prey
radiate diversely in shapes and colors
Sea Cucumberselongated body and leathery
skinGenerally scavengers,
feeding on debrisCommunicate through
sending hormone signals through the water
body wall can be loosened and tightened at willIf it wants to squeeze
through a small gap it can essentially liquefy its body and pour into the space.
Sea Urchinssmall, spiny, globular
creaturesmove slowly, feeding
mostly on algaelight touch elicits a
prompt and visible reaction from the spines, which converge toward the point that has been touched
Sand Dollars
have a skin of moveable spines
when it is found washed up on the beach, it is dead
has a set of five paired rows of pores that are arranged in a petal-like pattern
CrinoidsAlso known as sea lilies
or feather-starsa mouth on the top
surface that is surrounded by feeding arms
usually have a stem used to attach themselves to a substrate, but many live attached only as juveniles and become free-swimming as adults
Sourceshttp://diybio4beginners.blogspot.com/
2009/03/marine-bio-intro-to-echinoderms.html
http://www.starfish.ch/reef/echinoderms.htmlhttp://en.wikipedia.org/wiki/Starfishhttp://www.oceaninn.com/guides/echino.htmhttp://exploresea.com/?p=36http://store.justinhankins.com