Regeneration of Starfish

Name: Kono
Status: other
Grade: other
Location: IL

Question: My science book states that a cut up starfish can regrow into 
more starfish.  I want more information.  Can an arm regenerate a whole new 
starfish?  I have trouble believing this.
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Starfish, also known as sea stars, (they are not fish) are 
capable of regenerating even one arm into a whole new body.  This is only 
possible if the arm includes part of the central disc.  If you cut off only 
the tip of an arm, that tip will not regenerate, but the animal will grow 
another arm.  I have seen a single arm nearly 8 inches long with small 1/2 
inch arms growing off of it, it will eventually become a whole new sea star.  
If you cut a sea star in quarters, right down the center, each piece will grow 
into a whole new sea star.  I do not know how many pieces one can cut any one 
starfish into and still have each regenerate.  As long as a piece has part of 
the central disk, it should regenerate into a whole organism.  But if you cut 
a starfish in half, and then let it grow into an whole one before cutting it 
in half again, one should be able to do that indefinitely.

Jim Murray
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