Biology / Unit 10 Bio 2243 short lesson, about 20 seconds
Cnidarian Body Plan: Polyp and Medusa
Captions available
The idea
A cnidarian body takes one of two forms: a stationary, tubular polyp, or a free-swimming, bell-shaped medusa; some species alternate between both.
In practice
A sea anemone lives only as a polyp; a jellyfish spends most of its life as a medusa, though some pass through a polyp stage too.
Where people slip
Polyp and medusa name life-cycle stages within one species, not two separate cnidarian groups.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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