Download echinoderms

ECHINODERMS
Gabriel Dominguez
Marisa Ramunas
Biology – Period 8
What Is An Echinoderm?
 Echinoderms are characterized by spiny skin, an
internal skeleton, a water vascular system, and
suction-cup like structures called tube feet.
 Most adult echinoderms have a five-part radial
symmetry. Meaning that the body parts usually
occur in multiples of five and are arranged around
the center of the body like a wheel.
About Them
 The phylum name comes from the words echinos,
meaning “hedgehog”, and derma meaning “skin”.
 Kingdom = Amimalia
 Phylum = Echniodermata
Water Vascular System
 A unique feature of echinoderms is a system of
internal tubes called a water vascular system.
 The water vascular system, which is filled with fluid,
carries out many essential body functions in
echinoderms, including respiration, circulation, and
movement.
Feeding
 Echinoderms have several methods of feeding, for
example:
 Sea urchins use five-part jaw like structures to
scrape algae from rocks.
 Sea stars usually feed on mollusks such as clams and
mussels. Once the preys shell is open, the sea star
pushes its stomach out through its mouth, pours
out enzymes, and digest the mollusk in its own shell.
The sea star then pulls its stomach in and the some
what digested prey into its mouth.
Movement
• Most echinoderms move using tube feet.
• An echinoderms movement relies on its
structure of the endoskeleton.
• For example, sea urchins have movable spines
attached to the endoskeleton that help it get
around.
Reproduction
 Echinoderms reproduce by external fertilization.
 In most sea star species, the sexes are separate.
 Sperm are produced in testes, and the eggs are
produced in ovaries. Both types of gametes are shed
into open water, where fertilization takes place.
 The larvae swim around for a while and swim to the
bottom of the ocean, where they are able to
develop into adults.
Groups Of Echinoderms
(There are about 7,000 species!)
Sea Urchins & Sand
Dollars:
 Have large, solid plates
that form a box around
their internal organs.
 Eat large amounts of
algae.
Brittle Stars:
 Are commonly found
on coral reefs.
 They have slender,
flexible arms that help
them get away from
predators quickly.
 Are filter feeders.
 Hide by day and come
out at night.
Groups (cont.)
Sea Cucumbers:
 Look like warty,
moving pickles.
 Are detritus feeders
that move along the
sea floor while sucking
up organic matter and
the remains of other
animals and plants.
Sea Stars:
 Best-known group of
echinoderms.
 They move by creeping
slowly across the
ocean floor.
 Most are carnivorous.
Groups (cont.)
Sea Lilies & Feather Stars:
 Are filter feeders.
 Have long feathery arms.
 Makes up the oldest class of echinoderms.
 Live on top of coral reefs.
Pictures Of The Groups
of Echinoderms
Ecology Of Echinoderms
 In many areas, a sudden rise or fall in the number of
echinoderms can cause major changes in population
of other organisms.
 Sea urchins help control the distribution of algae.
 Sea stars are important predators in the ocean
because it helps control the number of other
organisms such as clams and coral.
THE
END :D