Transcript What are waves?

Echinoderms
Sea Star
Sea Cucumber
Brittle Star
Urchin
Sand Dollar (Keyhole
Urchin)
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Planet
Phylum Echinodermata
“Spiny skin”
Radial symmetry – 5 parts or
multiples of 5
Water vascular system –
hydraulic pressure system for
movement
Water Vascular System
WVS Operation
Water enters through madreporite
Through tube system to ampullae
of feet
Muscle contracts - water ejected
onto foot – suction
Muscle relaxes – water back into
ampullae – no suction
Skeletons
Plates under skin (some fused)
or spicules (endoskeleton)
Ca(CO3) – like mollusks
Projections
Sea Stars
Flexible – plates of skeleton
with muscles
Ambulacral groove with tube
feet
Mouth and anus
Eyespots sense light
Sea Star Feeding
Diet – mollusks, coral
Opens shells with tube feet
Extrudes stomach
Liquefies mollusk
Sea Star Dissection Lab
Brittle Stars
Distinct central disk
Tube feet have no suction –
send food to mouth
Arms for locomotion
Mouths with teeth
No anus
Regeneration
Need 1/5 of central disk and 1
arm to regenerate
Sea Urchins
Test
Mouth and anus
Ball and socket spines
Spines and tube feet for
movement
Sea Urchins
Algae-eaters and scavengers
Mouth with teeth (Aristotle’s
Lantern)
Sand Dollars
Flat sea urchins
Short spines
Sea Cucumber
Elongated body
Small skeletal fragments
Modified tube feet for tentacles
on oral end