No it is only humans that diet. All other living things just eat what they can get.
http://animalstime.com/starfish-facts-kids-starfish-diet-habitat/
The earliest known Echinoderm is from the Vendian period 560 million years ago. Starfish branched off sometime after this, possibly in the Ordovician.
food
No mammals existed in the Ordovician
It depends on the starfish. Common Starfish or Northern Sea Stars can become prey to fish, crabs, lobsters and the such although they aren't a part of a staple diet for any species that I'm aware of.
Algae was the dominant plant of the Ordovician. There were little to no other plants (other then algae) during the Ordovician. In the Ordovician, the common types of algae were Stromatolites (Blue green algae), and Tetradium (Red algae).
Jellyfish can sting you generally. Starfish cannot. Jellyfish are cnidarians and starfish are echinoderms. Jellyfish are 95% water. Starfish are not. Jellyfish can sometimes get quite huge, weighing over 500 pounds and some jellyfish have tentacles 100 feet long. Starfish don't get that big. Their diet is different. Their reproduction differs.
Sea stars eat clams, mollusks, oysters, coral in the reefs, and some eat other sea stars.
The Ordovician lasted for 47 million years from 490 to 443 Million Years Ago.
Starfish as a species mainly eat meat, though there are a few starfish that do eat rotting plants found on the sea floor. Some starfish focus on detritus --- meaning they eat just about anything that is decomposing. The main diet of starfish are crustaceans i.e. claims, sea snails, oysters, hermit crabs, and other mollusks. Starfish are opportunistic and will eat any slow moving or dieing fish. At times starfish will even eat other starfish.
The Ordovician lasted for 47 million years from 490 to 443 Million Years Ago.
nautiloids