Sea star regeneration

Sea stars have an awesome ability to regenerate lost limbs, even growing a whole new sea star from one arm and a portion of the central disc.  Here are some of the sea stars that students have found in the process of regeneration.  As you can see there can be some mistakes made in the process.

Growing back two arms.

In the process of growing four arms.

Oops, you are only supposed to have five arms!

Hmmm...do you have five arms or six?