Starfish Dissection

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There's are over 1,500 different species of starfish that live from anywhere from near the top of the ocean to the abyssal depths of the ocean. To help the starfish breathe, it has what is called the Hydraulic System which helps with gas exchange as well as moving and eating. This system is a series of canals that help transport different chemicals into the feet and lateral canals. In order to eat, the starfish takes in food from its mouth in the central disc and is moved into its gut (located towards the extends of the arms). From there it travels into many different tubes and canals and eventually the starfish will secret digestive enzymes which will absorb nutrients from the food. Generally the starfish tends to eat small fish, clams, oysters, and anthropods. The reason the starfish can eat animals that are larger then them Is because they are able to digest food outside their body. An interesting fact is that a starfish can produce both sexually and asexually and the oldest starfish was about 34 years old.

Here is a terrific video describing the dissection of a starfish (first link, ignore second link):

http://youtu.be/cEvXGt-r_DE

http://youtu.beSources: 

http://www.carolina.com/pdf/activities-articles/anatomy-starfish.pdf