Humans have direct development, a closed circulatory system, well-developed eyes, and large brains. Which mollusk also shares these features?

Question

A.  Chiton
B.  Slug
C.  Octopus
D.  Nudibranch

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 cephalopods?

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.  Octopus

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses cephalopods.
· 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 cephalopods?
        o The more than 700 species of cephalopods are strictly marine, and typically swift, active predators.
        o They are the only mollusks with a closed circulatory system.
        o Another difference with many other mollusks is that cephalopods have direct development—that is, they lack a larval stage, hatching as miniature adults.
        o The foot has evolved into a series of arms equipped with suction cups, adhesive structures, or hooks that seize prey.
        o After snaring prey with its arms, a cephalopod bites the prey with its strong, beaklike jaws, then pulls it into its mouth by the action of the radula.
        o Cephalopods have the largest relative brain sizes among invertebrates and highly developed nervous systems. Cephalopod eyes are large and similar to those of vertebrates, although they evolved independently.
        o Aside from the chambered nautiluses, living cephalopods lack an external shell.

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Which mollusks have direct development (lack a larval stage)? Slug and octopus.
        o Which mollusk has a closed circulatory system? Octopus.
        o Which mollusk has well-developed eyes? Octopus.
        o Which mollusk has a large brain? Octopus.

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 the octopus and other cephalopods have many features unique amongst the mollusks?