Echinoderms

1
Youre not seeing things. There are isopods in
that fishs mouth. And theyre not simply hiding
in there theyve completely replaced the fishs
tongue. Meet the tongue-eating isopod (Cymothoa
exigua).
2
http//www.youtube.com/watch?vFo-gcZ78Ij0modere
latedsearch
3
Echinoderms
The spiny misfits
4
Characteristics

• Larvae have bilateral and adults have radial
  symmetry
• No head!
• Endoskeleton
• Water vascular system
• Classes Asteroidea, Ophiuroidea, Echinoidea,
  Holothuroidea, Crinoidea

5
Water Vascular System

• Network of water filled canals
• Tube feet extend when filled with water thru
  canals
• locomotion and attachment

• Connects to the outside by the madreporite

6
Asteroidea- sea stars

• Slow moving, flexible arms
• Predators of bivalves, snails, barnacles
  (slow-moving or attached animals)
• Feed by everting stomach thru mouth

http//www.youtube.com/watch?vpoES7StHc9s
http//www.youtube.com/watch?vprCeHDa7GTQ
7
Ophiuroidea- brittles stars

• Arms very flexible and can move quickly
• Deposit feeders
• Largest group of echinos but stay hidden

8
Echinoidea- sea urchins, sand dollars

• Round hard endoskeleton with movable spines
• Graze on sea weed and sea grasses as well as
  scavenge
• Aristotles lantern- special mouth and jaw parts

http//www.youtube.com/watch?vNdgyaRFgvQQ
9
(No Transcript)
10
Holothuroidea- sea cucumbers

• Worm like
• Deposit feeders
• Cool defense mechanisms
• Secrete toxins
• Discharge mucus and toxins thru their anus
• Eviscerate guts thru mouth or anus
• (theyll grow back)

http//www.youtube.com/watch?vlKWSLg5PDiU
http//www.youtube.com/watch?vvsLBOkYLLeI
11
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?vaffSVrHHDfkmodere
latedsearch
http//www.youtube.com/watch?vm7X6q-dfslQmodere
latedsearch
12
Body

• Most are carnivorous with a complete digestive
  tract
• Nervous system is simple looking but these orgs
  have complex behavior
• Separate sexes with gametes released into the
  water
• Regeneration is highly developed