What is alimentary canal?

Is the gastrovascular cavity older than the alimentary canal?

• I know that it is the simpler form of extracellular digestion, but did the gastrovascular cavity appear before the alimentary canal.

• Answer:

  Hey, the gastrovascular cavity is older from an embryonic development stand point. The alimentary canal evolved later on, following animals that excrete wastes out of the same hole they eat. The alimentary canal evolved to allow food to be excreted through the bottom end of the body, also known as the anus. So all in all, the archenteron- or primitive gut, evolved into a gastrovascular cavity much earlier evolutionarily than the alimentary canal.