annelids vs mollusks

[dat_student]

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I read somewhere that annelids exhibit higher evolutionary complexity than a mollusk. What do you think ? I always thought it was the other way around (i.e. thought mollusks exhibit higher complexity).

 

[kew]

Annelids have a closed circ system while mollusks have an open. But whose to say if this is to explain why it is or isn't considered to be the winner in complexity. But I just thought the fact would help decide.

 

[mochafreak]

Is it clear which one became the first coelomate? That seems like a toss-up...