Chapter 6 and 7 Flashcards
what is the most diverse group of telosts?
Perciformes
what are the four primary functions of a fish’s head?
1) feeding and respiration
2) sensory perception and coordination
how did a fish’s body change as jaws started to evolve?
- predatory life style
- speed
- elongate streamlined shape
- paired fins for stabilization and maneuverability
what are two very important structural innovations?
1) jaws and teeth
2) paired fins
what were the earliest fishes jaws made of?
endochondral bone
what is the upper and lower jaw called in chondrichtheyes?
- palatoquadrate cartilage
- mandibular cartilage
how does the premaxilla evolve?
begins in a small anterior position, both pre maxilla and maxilla bear teeth, but maxilla have the most.
premaxilla elongates, overlaps the maxilla, and assumes the tooth-bearing position of the upper jaw.
whats the development on the anterior end of evolved teleost’s maxilla called?
ascending process
what are the three principle categories of feeding?
i) hit and run
ii) filter feeding
iii) gape and suck
explain hit and run strategy
- used mostly by fast-swimming open water forms
- run down, engulf, swallow slower prey, or bite a chunk of them.
what is hit and run’s jaw requirements?
firm jaw construction and placement as well as large, powerful muscles to get the jaws shut firmly and quickly at the proper time
what ability does gape and suck feeding depend on?
the ability to create sufficient negative pressure to suck individual food items from the surrounding water
what form of feeding do the majority of fish have?
gape and suck
why dont gape and suck feeders require strong jaws?
the jaw rarely touches the prey, the jaw opens quickly and engulfs the prey whole.
in primitive actinopterygians, what is the lowering of the mandible or opening of the mouth dependant on?
lowering the floor of the throat. AKA the hyoid coupling
