Flashcards in Lec 10 Feedings II Deck (11):
What does the mouth do during gape and suck?
Floor of the mouth is lowered and the sides of the mouth cavity expands.
this increase in volume creates negative pressure, which results in sudden rush of water in the mouth.
What are oral valves?
membranous valves just inside the upper and lower jaws help prevent water from escaping anteriorly.
How does the water leave the mouth during gape and suck?
Trapped water is force out of the gills. Then the food is strained out by gill rakers and passed back to the esophagus.
What is hyoid coupling?
a biomechanical coupling responsible for opening the moutn in primitive actinopterygians.
What does the effectiveness of the suction in capturing prey depends on?
1. Degree to which mouth cavity can be expanded
2. suddenness to which the mouth cavity can be expanded.
What is opercular coupling?
mechanism for opening the mouth in derived actinopterygians.
What good is the opercular coupling when it does not involved negative pressure?
Development is necessary pre adaptation for fishes that browse along the rocks and coral. Picking up small prey from soft bottoms and bites chunks of coral. Fishes like parrotfish, wrasses, trigger fishes and a lot of perciform taxa. Still have the availability to gape and suck.
How is the mouth closed?
Contraction of large complex muscle called adductor mandibulae (cheek muscles).
Where did the adductor mandibulae originate, in the bones?
Bones of the suspensorium.
Two reasons why the adductor mandibulae is a very important muscle.