Phylum Echinodermata By Kayla Wilkinson

Class Asteroidea Sea stars Most have 5 rays Some may have more Rays are tapered and extended from the central disk Have an endoskeleton Water flows in and out the water vascular system through the madreporite

Class Asteroidea Have tube feet Have eyespots at the end of each ray To eat sea stars push their stomachs out their mouth and spread their mouth over their food Then enzymes turn the solid food into a liquid The stomach then pulls back into the body

Class Asteroidea They excrete waste out the anus Have pincer like pedicellariae that will pinch any animal that tries to crawl over it

Class Ophiuroidea Brittle stars Extremely fragile If you pick one up some of its rays will fall off This is their way of escape While the predator is messing with the broken off ray the brittle star can escape A new ray will regenerate within weeks

Class Ophiuroidea Don’t use tube feet for locomotion Propel themselves with the snake-like, slithering motion of their flexible rays Use tube feet to pass food particles up the rays and into the mouth

Class Echinoidea Sea urchins and sand dollars Globe- or disk-shaped animals covered with spines Don’t have rays Sand dollars have a five-petaled flower pattern on the surface Sand dollars covered with tiny, hair-like spines that are shed when the animal dies

Class Echinoidea Sand dollars have tube feet that come out of the petal-like marking of the upper surface They are modified into gills Tube feet on bottom used for bringing food particles to the mouth

Class Echinoidea Sea urchins look like pincushions Long usually pointed spines Have long slender tube feet that aid in locomotion Spines protect from predators Also aid in locomotion such as burrowing

Class Holothuroidea Sea cucumbers Leathery covering that allows them to be more flexible than any other echinoderms Move with tentacles and tube feet When threatened they will rupture their internal organs and release them out their anus Then regenerate them within a few weeks

Class Holothuroidea This confuses predators and the sea cucumber can get away Reproduce by shedding eggs and sperm into water where fertilization takes place

Class Crinoidea Sea lilies and feather stars Resemble plants Sea lilies only sessile echinoderms Feather stars are sessile during larval form only Adult feather stars use feathery arms to swim from place to place Use feathery rays to capture organic particles