Fishes That Have Swim Bladders Can Regulate Their Density And

question 67

Multiple Choice

Fishes that have swim bladders can regulate their density and, thus, their buoyancy. There are two types of swim bladder: physostomous and physoclistous. The ancestral version is the physostomous version, in which the swim bladder is connected to the oesophagus via a short tube (see the figure) . The fish fills this version by swimming to the surface, taking gulps of air, and directing them into the swim bladder. Air is removed from this version by "belching". The physoclistous version is more derived and has lost its connection to the oesophagus. Instead, gas enters and leaves the swim bladder via special circulatory mechanisms within the wall of the swim bladder.
-The presence of a swim bladder allows the typical ray-finned fish to stop swimming and still ________.

• A) effectively circulate its blood
• B) use its lateral line system
• C) use its swim bladder as a respiratory organ
• D) not sink