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Echinoderms
KNOWN SPECIES
11,579
0.49% of our world's living things are echinoderms
CHARACTERISTICS
- animals without a backbone (invertebrates), that also have no head, eyes, or brain
- they can be divided into matching sections branching from a central point
- usually with five arms
SIZE RANGE
less than 0.39 inch to 6.5 feet (1 centimeter to 2 meters)
WHERE THEY LIVE
in oceans
Here are just SOME of the world’s echinoderms:
chocolate chip sea cucumber
SCIENTIFIC NAME:
Isostichopus badionotus
sand dollar
SCIENTIFIC NAME:
Dendraster excentricus
bat star
SCIENTIFIC NAME:
Asterina miniata
blood star
SCIENTIFIC NAME:
Henricia leviuscula
sunflower sea star
SCIENTIFIC NAME:
Pycnopodia helianthoides
slate pencil urchin
SCIENTIFIC NAME:
Eucidaris tribuloides
Guess what?
When stressed, sea cucumbers may spit out all of their internal organs, but they can usually grow them back!
Image Credits:
Bat star, blood star, sand dollar, Gerald and Buff Corsi/© California Academy of Sciences; chocolate chip sea cucumber, © Hans Hillewaert/CC BY-SA 4.0; slate pencil urchin, Eugene Weber/ © California Academy of Sciences; sunflower seastar, Sherry Ballard/ © California Academy of Sciences.