Biology / Unit 12 Bio 2765 short lesson, about 20 seconds
Gastrovascular Cavity versus Alimentary Canal
Captions available
The idea
A gastrovascular cavity is a blind pouch with one opening serving as both mouth and anus; an alimentary canal is a tube with separate ends.
In practice
A jellyfish digests through a gastrovascular cavity; an earthworm's food travels one direction through a complete canal.
Where people slip
A one-opening system cannot process incoming and outgoing material at once — a two-opening canal allows continuous feeding.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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