Biology / Unit 10 Bio 2223 short lesson, about 20 seconds
Coelom Types: Acoelomate, Pseudocoelomate, Coelomate
Captions available
The idea
An acoelomate has no body cavity between gut and body wall; a pseudocoelomate has one lined incompletely by mesoderm; a coelomate is fully mesoderm-lined.
In practice
A flatworm is acoelomate, a roundworm is pseudocoelomate, and an earthworm's fully lined coelom cushions its organs.
Where people slip
A cavity's presence and lining, not body size, is what this criterion classifies — some pseudocoelomates are larger than some coelomates.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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