Download 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=