What is a simple way for determining if an annelid is a polychaete or a clitellate?

Question

A.  The number of segments
B.  Possession of a closed circulatory system
C.  The amount of chaetae (setae)
D.  The layout of the digestive system

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?

Gather Content
· What do you already know about annelids?

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?


Answer 1

C.  The amount of chaetae (setae)

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses annelids.
· What type of thinking is required?
        o This question is asking you to take what you already know and apply it to this unfamiliar situation.

Gather Content
· What do you already know about annelids?
        o The annelids comprise two major classes, Polychaeta and Clitellata (which combines the old groups Oligochaeta and Hirudinea).
        o Polychaetes (“many chaetae”) are marine annelids characterized by numerous bristles, or setae/chaetae.
        o The Clitellata include earthworms and leeches. They haver fewer chaetae (setae). (“Oligochaete" means few chaetae.)

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o The most obvious anatomical difference between polychaetes and clitellates is reflected in their names: polychaetes have more chaetae (setae).

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that polychaetes are “bristly worms”?