Transcript Echinoderms
http://www.youtube.com/watch?v=Fo-gcZ78Ij0&mode=related&search= Echinoderms The spiny misfits General Characteristics • Larvae have bilateral and adults have radial symmetry • No head! • Endoskeleton- calcium carbonate • Water vascular system • Pattern of development in embryos is more similar to vertebrates General Characteristics • Number of arms is in multiples of 5 • Separate sexes • Nerve ring • Open circulatory system • Body cavity Body • Most are carnivorous with a complete digestive tract • Nervous system is simple looking but these orgs have complex behavior • Regeneration is highly developed • Network of water filled canals • Connects to the outside by a pore called the madreporite Water Vascular System • Tube feet extend when filled with water thru canals • Used for locomotion and attachment CLASSES OF ECHINOS Asteroidea Ophiuroidea Echinoidea Holothuroidea Crinoidea Asteroidea- sea stars • Slow moving, flexible arms • Predators of bivalves, snails, barnacles (slowmoving or attached animals) • Feed by everting stomach thru mouth http://www.youtube.com/watch?v=prCeHDa7GTQ Ophiuroidea- brittle stars • Arms very flexible and can move quickly • Deposit feeders • Largest group of echinos but stay hidden http://www.youtube.com/watch?v=XV0KAr_M-7w&feature=related Echinoidea- sea urchins, sand dollars • Round hard endoskeleton with movable spines • Graze on sea weed and sea grasses as well as scavenge • Aristotle’s lantern- special mouth and jaw parts http://www.youtube.com/watch?v=SRAfjvws13E http://www.youtube.com/watch?v=NdgyaRFgvQQ Holothuroidea- sea cucumbers • Worm like • Deposit feeders • Interesting defense mechanisms –Secrete toxins –Discharge mucus and toxins thru their anus –Eviscerate guts thru mouth or http://www.youtube.com/watch?v=lKWSLg5PDiU anus http://www.youtube.com/watch?v=vsLBOkYLLeI Crinoidea- feather stars and sea lilies • Suspension feeders with feathery arms for feeding • Deep water and either attached to the bottom or crawl http://www.youtube.com/watch?v=affSVrHHDfk&mode=related&search= http://www.youtube.com/watch?v=m7X6q-dfslQ&mode=related&search=