Ally McCabe
Echinoderms
For Dummies
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Ally McCabe
Echinoderms
Classification and Examples!
Echinoderms
Kingdom: Animals
Phylum: Echinoderms
Sea Star
Sea Urchin
Sea Cucumber
Class: Asteroidea
Class: Echinoide
Order: Forcipulatida
Order: Echinoida
Order: Aspidochirotida
Family: Asteriidae
Family: Strongylocentrotidae
Family: Stichopodidae
Genus: Asterias
Genus: Strongylocentrotus
Genus: Parastichopus
Species: A. rubens
Species: S. purpuratus
Species: P. parvimensis
Class: Holothuroideaia
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Echinoderms
Sea stars
Body Symmetry
Sea Stars have radial symmetry with several arms!
There are typically five arms that radiate from a central body.
Here is an example of the symmetry within a Sea Star:
Fun Fact!:
If a Sea Star has more than 5 legs, than the number of legs will be a
multiple of 5. This means either 5, 10, or 15 legs!
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Echinoderms
Sea Stars
Nervous System
Sea Stars have something called a nerve ring. This nerve ring is their
simple nervous system!
The nerve ring surrounds their mouth, and radial nerves branch off from the
ring and go down each arm!
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Echinoderms
Sea Stars
Digestive System
Sea Stars have a complete digestive system!
Their mouth is centred on their underside, and their anus is centred on their
top.
Sea Stars actually have two stomachs!
One on the inside and one on the outside. Food moves from the cardiac
stomach and then to the pyloric stomach.
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Echinoderms
Sea Stars
Respiratory System
Sea Stars have no respiratory organ systems!
They use gas exchange in through tube feet and out through the hole at
their top. Report on Animals, Page 6
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Echinoderms
Sea Stars
How They Move
Did you know that Sea Stars actually move!
They have a water-vascular system and tube feet to allow movement.
They move water into their tiny feet to expand them, and muscles in the
feet are used to retract them. This causes suction that they use to move!
This is an up-close image of Sea Stars’ tube feet!
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Echinoderms
Sea Stars
Reproduction
Sea Stars reproduce sexually, as they have separate sexes (males and
females)!
For sexual reproduction, swimming larva called bipinnaria are produced.
Fun Fact!:
Sea Stars also have the ability to regenerate!
This means that if you break a Sea Star in half, it can regrow into two new
whole Sea Stars! Also if a Sea Star looses an arm, it can grow back that
arm!
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Echinoderms
Sea Stars
Fun Facts!
1.
A Sea Star, sometimes referred to as a
Starfish, is not actually a fish!
2. Sea Stars cannot survive in fresh water!
They only live in oceans.
3. There are thousands of different species of
Sea Stars!
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References:
Starfish. (n.d.). Retrieved December 21, 2016, from http://
ramdigestivesystem.weebly.com/starfish.html
How Starfish Move. (n.d.). Retrieved December 21, 2016, from http://
www.madreporite.com/science/movement.htm
Society, N. G. (n.d.). Starfish (Sea Stars), Starfish (Sea Star) Pictures, Starfish
(Sea Star) Facts. Retrieved December 21, 2016, from http://
animals.nationalgeographic.com/animals/invertebrates/starfish/
Respiration & Circulation. (n.d.). Retrieved December 21, 2016, from http://
starfishswag.weebly.com/respiration--circulation.html
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