Sharks have a number of fleshy gill slits instead of a bony gill cover. How does this affect their behavior?

Question

A.  Their movements are slow due to low oxygen.
B.  They live only in highly oxygenated water.
C.  They keep swimming to move water across their gills.
D.  They do not maintain neutral buoyancy.

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 the operculum?

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.  They keep swimming to move water across their gills.

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses the operculum.
· 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 the operculum?
        o Most bony fishes have a hard plate called the operculum, or gill cover, that covers the gills on each side of the head. Sharks lack an operculum.
        o In bony fish, flexing the operculum pumps water over the gills. The gills are suspended in the pharyngeal slits that form a passageway between the pharynx and the outside of the fish’s body. When the operculum is closed, it seals off the exit. When the mouth is open, closing the operculum increases the volume of the mouth cavity, so that water is drawn into the mouth. When the mouth is closed, opening the operculum decreases the volume of the mouth cavity, forcing water past the gills to the outside. Using this very efficient bellows, bony fishes can pass water over the gills while remaining stationary in the water.

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Since sharks lack an operculum (or gill cover), they keep moving to keep oxygenated water passing over the gills.

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 reason sharks must keep moving for respiration is because they lack an operculum, or gill cover?