According to the modern classification scheme, which animal would be a spider's closest relative?

Question

A.  A snail
B.  An earthworm
C.  A tapeworm
D.  A roundworm
E.  A squid

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 protostome phylogeny?

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

D.  A roundworm

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses protostome phylogeny.
· 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 protostome phylogeny?
        o The spider is an arthropod. Arthropods are part of Ecdysozoa – the molting animals.
        o The other phyla in Ecdysozoa are: Loricifera, Kinorhyncha, Nematoda, Tardigrada, and Onychophora.

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 common representative of these other ecdysozoan groups is the roundworm – a member of Nematoda.

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 arthropods and nematodes are closely related?