Changes

==Digestion==

==Digestion==

Starfish eat almost anything that cannot easily escape, but mainly [[bivalves]]. They eat these by using their tube feet as suction cups to prise a small gap in the bivalve’s shell, and then everting their own stomach through their mouth opening and extending it into the shell, using their digestive juices to liquefy the creature inside and then wafting the liquefied juices into its mouth with its tube feet. This enables a starfish to hunt much larger prey than it could actually fit into its mouth. Starfish help the intertidal [[ecosystem]] stay in balance by eating mussels, which would otherwise push other organisms out. <ref> http://oceanlink.island.net/ask/echino.html <ref> The crown-of-thorns starfish (Acanthaster planci), which feeds on [[coral]], is decimating [[coral reefs]] off the [[Philippines]] and [[Australia]].  

Starfish eat almost anything that cannot easily escape, but mainly [[bivalves]]. They eat these by using their tube feet as suction cups to prise a small gap in the bivalve’s shell, and then everting their own stomach through their mouth opening and extending it into the shell, using their digestive juices to liquefy the creature inside and then wafting the liquefied juices into its mouth with its tube feet. This enables a starfish to hunt much larger prey than it could actually fit into its mouth. Starfish help the intertidal [[ecosystem]] stay in balance by eating mussels, which would otherwise push other organisms out. <ref> http://oceanlink.island.net/ask/echino.html </ref> The crown-of-thorns starfish (Acanthaster planci), which feeds on [[coral]], is decimating [[coral reefs]] off the [[Philippines]] and [[Australia]].  

Starfish have a [[mouth]] in the middle of their underside (the ‘oral’ side) and an [[anus]] on their upper surface (the ‘aboral’ side). The mouth connects to the first of two stomachs – the cardiac stomach – which connects to the pyloric stomach. This connects to the anus and also to a pyloric [[cecum]], which extends into each ray. The cardiac stomach and the pyloric ceca produce digestive juices. Digested material is absorbed into the body through the pyloric ceca.<ref>http://www.vsf.cape.com/~jdale/science/science.htm</ref>

Starfish have a [[mouth]] in the middle of their underside (the ‘oral’ side) and an [[anus]] on their upper surface (the ‘aboral’ side). The mouth connects to the first of two stomachs – the cardiac stomach – which connects to the pyloric stomach. This connects to the anus and also to a pyloric [[cecum]], which extends into each ray. The cardiac stomach and the pyloric ceca produce digestive juices. Digested material is absorbed into the body through the pyloric ceca.<ref>http://www.vsf.cape.com/~jdale/science/science.htm</ref>