http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/echinoderms.gif
Phylum Echinodermata
Phylum Characteristics:
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Name: (Greek) echinos = spiny; derma =skin
Calcareous endoskeleton in the form of ossicles
Most adults with pentaradial symmetry
Larva with bilateral symmetry
Water-vascular system (including tube feet) for
locomotion, attachment, and/or feeding
• Digestive tract
• Hemal system (to circulate fluids and possibly
distribute nutrients)
• Nervous system (= nerve net, nerve ring, and
radial nerves)
Class Crinoidea
• Sea Lilies and feather stars
• Most primitive of all living echinoderms
• Sea Lilies attach to substrate by a stalk
– Unattached end = crown (of 5 branched arms)
– Double row of tube feet along each arm
– Crown attached to stalk at calyx
– Stalk may have cirri (projections)
*feather stars lack a stalk and are swim/crawl using
their arms
http://www.sciencenewsforkids.org/articles/20
051026/a919_1857.jpg
http://glennandert.files.wordpress.com/2008/06/dsc_1989_blackandwhitecrinoid_forblog.jpg
http://digsfossils.com/fossils/pics/crinoid-sketch.gif
http://www.nova.edu/ocean/
messing/crinoids/8%20Feedin
g%20mechanism_files/image
004.jpg
Sea Lilies
http://palaeo.gly.bris.ac.uk/Palaeofiles/
Fossilgroups/Ophiuroidea/Feather_Star
_large.jpg
http://www.teara.govt.nz/files/p5199ryp.jpg
http://images.google.com/imgres?imgurl=http://www.wildsingapore.com/wildfacts/echinodermata/crinoidea/red
/080425cyrd1818m3.jpg&imgrefurl=http://www.wildsingapore.com/wildfacts/echinodermata/crinoidea/red.htm
&usg=__paR9PIvtJNr8UapDkH_SyS1u0M=&h=216&w=216&sz=59&hl=en&start=33&itbs=1&tbnid=TcZY59QLNb31lM:&tbnh=107&tbnw=107&p
rev=/images%3Fq%3Dfeather%2Bstars%26gbv%3D2%26ndsp%3D18%26hl%3Den%26sa%3DN%26start%3D18
Feather Stars
• Suspension/Filter feeding: Tube feet catch
prey and cilia in ambulacral groove carry it to
mouth
• Lack nerve ring
• Can be dioecious or monoecious (male
gametes develop before female gametes)
• Fertilization may be external or embryos may
be brooded on arms of adult
• Capable of regeneration
Class Asteroidea
• Sea Stars (and Sea Daises?)
• 5 arms around a central disk, each with an
ambulacral groove and tube feet
• Some arms may have photoreceptors/ocelli on
tube feet at tips
• Dermal Branchiae (thin folds of body) function
in gas exchange
• Some have pedicellariae (pincherlike
structures) which may help clean & protect
• Feed on snails, bivalves, crustaceans, polychaetes,
corals, detritus, etc.
https://yhsbiology.wikispaces.com/file/view/starfish-1.jpg/33144125/starfish-1.jpg
• 2 sides: oral/aboral
– Aboral side contains
anus and madreporite
(connects ring canal to
outside -helps to
replace water into
water-vascular system)
– Oral side has mouth
connected to
esophagus, stomach
(with 2 regions), and
short intestine
http://universe-review.ca/I10-82-starfish.jpg
http://www.cals.ncsu.edu/course/zo150/mozley/fall/Asterskin.jpg
http://www.2classnotes.com/images/12/
science/Zoology/Aboral_surface_of_star_
fish.gif
• Known for regeneration (asexual reproduction)
• Most Dioecious (internal difference)
– 2 gonads in each arm
• External fertilization
http://sharonminsuk.com/LabBio/images/StarfishStagesBig.jpg
http://allencentre.wikispaces.com/fi
le/view/starfish_larva.jpg/31302621
/starfish_larva.jpg
http://museumvictoria.com.au/pages/3349/gallery/tinystar.jpg
http://mrbarlow.files.wordpress.com/2008/03/giant-sea-stars.jpg
http://images.travelpod.com/users/andy
12pam03/2.1237847400.crown-ofthorns-sea-star-coral-killerxx.jpg
http://www.tankedup-imaging.com/images/blue_sea_star.jpg
http://photography.nationalgeographic.com/staticfil
es/NGS/Shared/StaticFiles/Photography/Images/Con
tent/necklace-sea-star-696678-sw.jpg
http://4.bp.blogspot.com/_9jTkGowIILg/SLpqwg
Th2WI/AAAAAAAAFxM/QaFw1gwPLo/s400/changi310808p01.JPG