Transcript Echinodermsx

Echinoderms
(Sea Stars, Sea Urchins,
Sand Dollars, Sea
Cucumbers)
General Stuff
• Echinoderms belong to the Phylum
Echinodermata, meaning “hedgehog
skin”.
• Echinoderms have spiny skins.
• They have radial symmetry.
• They lack body segmentation.
• There are more than 5000 species of
Echinoderms.
• Types are sea stars, sea urchins, sea
cucumbers, sand dollars.
Types of Echinoderms
Sea Stars- Starfish
• Have radial symmetry.
• Most starfish have 5 “arms”or rays.
• Starfish have tube feet for locomotion, and
strong suction to hold them in place.
• They also have a water vascular system
that enables them to store water in their
tube feet so they can survive while the tide
is out.
• They breathe through small gills in their
skin.
• Their mouths are located on the underside
of their bodies.
• Starfish can regenerate. (must have the
central disc attached).
More Starfish Stuff
• Sea Stars are carnivorous, yup, they eat
mostly shellfish, snails, and barnacles.
• They use their tube feet to pry open the
shells and then throw their own stomachs
out into the shell to digest the meat before
it’s brought back into its body!
• There are lots of different types of Sea
Stars, about 2000 different kinds.
• Most Sea Stars have spiny skin.
Sea Star Anatomy
STARFISH
LATIN
meaning
ANIMALIA
KINGDOM _____________
ECHINODERMATA “spiny skin”
PHYLUM
_____________________________
ASTEROIDEA
“star-like”
CLASS
Starfish (sea stars)
Come in a variety of colors
http://www.trinitykids.org/Portals/2/graphics/starfish.jpg
http://www.perspective.com/nature/animalia/starfish.html
http://www.perspective.com/nature/animalia/starfish.html
http://www.deepseaimages.com/dsilibrary/data/1143/706-28a.jpg
. . . and sizes
http://bcuniversal.com/familyimages/Natasha%20&%20Starfish%20Seattle%202000.JPG
Not all starfish have 5 arms
http://www.perspective.com/nature/animalia/starfish.html
http://www.seashells.org/identcatagories/starfish.htm
SYMMETRY
ADULTS- Radial
LARVA- Bilateral
http://www.uic.edu/classes/bios/bios100/labs/radial.jpg
ORAL VIEW
http://wwwbio200.nsm.buffalo.edu/labs/tutor/Starfish/Starfish02D.html
http://wwwbio200.nsm.buffalo.edu/labs/tutor/Starfish
SPINY SKIN
http://wwwbio200.nsm.buffalo.edu/labs/tutor/Starfish
SPINES for protection connect to
ENDOSKELETON inside underneath skin
OSSICLES
Calcium carbonate plates
form endoskeleton inside
http://ebiomedia.com/prod/BOechinoderms.html
Skin gills between spines
http://wwwbio200.nsm.buffalo.edu/labs/tutor/Starfish
EXCHANGE GASES and
EXCRETE NITROGEN WASTE
TUBE FEET surfaces
http://wwwbio200.nsm.buffalo.edu/labs/tutor/Starfish
Can exchange gases and excrete nitrogen
EYESPOTS
Sense light/dark
Madreporite
Opening to water vascular system
http://ebiomedia.com/gall/skin/skin1.html
TUBE FEET
Used for feeding & locomotion
http://www.scsc.k12.ar.us/2001Outwest/PacificNaturalHistory/Projects/ReynoldsJ/starfish.jpg
DIGESTIVE GLAND
Makes BILE
ABSORBS NUTRIENTS
http://www.k-state.edu/organismic/echinoderms_and_protochordates.htm
2 part STOMACH
DIGESTIVE SYSTEM
ANUS
DIGESTIVE
GLANDS
DIGESTIVE
GLANDS
MOUTH
Image by Riedell
Saona Island
London Museum
How Starfish Eat
QuickTime™ and a
decompressor
are needed to see this picture.
Dancing With the Stars!
ASEXUAL REPRODUCTION
Ability to self amputate
AUTOTOMY
Ability to regrow lost parts
REGENERATION
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/Regeneration.html
Spawning
• Starfish reproduce sexually by
spawning. Spawning means that
the sex cells are released into
the water. Starfish gather in
groups to reproduce, which
increases the likelihood the
sperm and eggs will find each
other. Starfish have sexual
organs, or gonads, in each arm.
During a breeding season the
males' gonads fill with sperm and
the females' gonads fill with
eggs. When starfish spawn, the
males release sperm and the
females release eggs in great
numbers. Female starfish may
release millions of tiny eggs into
the water during a spawning
session.
Sea Urchins
• Sea Urchins look like big pin cushions.
• They use these spines for protection
against predators.
• The spines also act like stilts to keep their
bodies up off the ground so the tube feet
can pull them around!
• They eat mostly algae.
• They live mostly attached to rocky
crevices, which protect them from waves
and tide surges.
• They have become a popular item to eat
and are being harvested in alarming
numbers.
Sea Urchin Anatomy
Mating
• Most sea-urchin species have separate
sexes and release their gametes into
the sea at breeding time in the spring.
There are 5 gonads communicating with
the outside via 5 gonopores visible, as
shown here, as 5 holes in the test. The
gonads are discrete and easily
accessible, leading to many studies on
seasonal cycling of growth, maturation,
and spawning.
Sand Dollars
• Are found on the sandy shore or
muddy bottoms.
• They feed standing on edge with
their tube feet acting as filters.
• The star pattern seen on top of the
sand dollars is actually caused by
special breathing tube feet!
• The mouth is found on the under
side of the animal.
Sand Dollar Anatomy
Sea Cucumbers
• Sea cucumbers have tentacles at their
mouth openings to grab and hold food.
• They look like snails, but have radial
symmetry and spiny bodies like all other
echinoderms.
• When provoked, or annoyed, Sea
cucumbers throw out their intestines to
entangle, frighten, or confuse their
predator! Then the intestines are
regenerated.They are filter feeders and
have a sticky slime that covers their
tentacles and lets them grab particles
from the ocean floor.
• Sea Cucumbers are considered a delicacy
Mating
•
Sea Cucumbers have a very interesting way of mating. They are not in
the least bit intimate and it involves little to no interaction with the other
Sea Cucumbers. What they do is that the males just release sperm
into the water and the females just release their eggs into the water. It
is basically all luck on whether or not the organisms are close to other
organisms during mating. Each organism can release thousands of
gametes at a time, for females up to 130,000 eggs at a time, which are
hopefully fertilized in the water (external fertilization) and become
larvae. The Sea Cucumber becomes sexually mature at around year
two of an eight year life span. There is no exact number of
chromosomes that I can put down for the Sea Cucumber as the results
of various studies came back with varying results for some odd reason
Interesting Stuff
• Some Sea cucumbers are quite
poisonous, and the poison has been used
as an inhibitor of Cancer growth.
• Sea Cucumbers secrete a sticky glue as a
defense mechanism that has been used as
a bandage to bind wounds.
• Sea Cucumbers will stick each tentacle in
their mouths, lick them off and then do the
same with the next one- kind of like you
licking your fingers after eating!
Sea Cucumber Anatomy