Chapter 3 Flashcards
what are the two aspects of locomotion?
forward progress and directional control
how do the 5 types of swimming modes most differ? (3 ways)
i) the proportion of the body that undulates (oscillates)
ii) the amount that the head moves (yaw)
iii) morphology
Sinusoidal undulation
throwing the body into a series of successive ‘S’-shaped curves
What is the most primitive mode of swimming in vertebrates?
Anguilliform
All fishes use which mode of swimming at least once in their life?
sinusoidal
what are the three lines of evidence that support the theory of Anguilliform’s primitiveness?
i) sideways undulation
ii) most fishes start out using anuilliform in their larval stages
iii) vetebrates are bilaterally symmetrical
briefly describe the motion of anguilliform locomotion
successive waves of muscular contraction pass along alternate sides of the body.
the lateral components of force cancel each other out, resulting movement is forward
how do anguilliformes slow down or stop?
hold the curved body rigid,
anguilliform swimming is related to what body type?
long, slender bodies with reduced or absent caudal fins
is high speed possible with anguilliform swimming?
nope
How are caudal swimmers different from anguilliform swimmers?
the distribution of body bulk and the effect of contracting the body muscles in the tail region.
what did Langerhans and Reznick’s research suggest?
that subtle differences between stream environments can lead to selection for different swimming morphologies within the same species.
what are the four sub-categories of carangiform swimming methods?
Subcarangiform, Carangiform, Thunniform, Ostraciiform
how much musculature is needed for subcarangiform swimming?
two thirds
What type of swimmer is a salmon?
subcarangiform
is the caudal fin the major propulsive force in subcanrangiform swimming?
nope. you could cut it off and the suckers would still go. The caudal fin helps with rapid acceleration, fast turning, and high speed maneuverability.
what part of the body is used for canrangiform locomotion?
only the posterior 1/3 part of the body
what two major evolutionary developments occurred?
i) become more laterally compressed and deeper bodied, unpaired fins became stiffened with spines
ii) depth of the caudal peduncle has become greatly reduced, reducing turbulence and drag, increasing the frequency in which the tail beats.
how has the development of keels impacted the drag?
increase the hydrodynamic shape of the the caudal peduncle
how is thrust generated in Thunniform swimmers?
almost exclusively by a high (lunate), stiff and deeply forked caudal fin mounted on an extremely narrow caudal peduncle, typically with stiff keels.
are thunniform swimmers always warm blooded?
yup
even though Oscillaformes vary greatly in body shape, what can be common of these swimmers?
they tend to be fishes with bodies incaed in armour and or weaponry
what the heck is Tetraodontiform locomotion?
fishes who propel themselves by passing waves of movement down their elongate dorsal and/or anal fins
what do you call fish who propel themselves by rapid undulation of the pectoral fins?
Rajiform or Labriform locomotion
name some non-swimming locomotions
jet propulsion, terrestrial locomotion, walking and burrowing, jumping, gliding, and true flying.
name some nearly finless fishes
hagfish, lamprey, true eels, swamp eels
name three roles that fins play
i) aid/produce forward movement
ii) guide the course of forward movement
iii) system of brakes, mechanism for backing up
what is a major evolutionary theme for fins?
increasing functional efficiency and specialization.
what are the five regions for fin placement over the body?
i) anterior zone of rudders
ii) posterior zone of rudders
iii) zone of keels
iv) zone of stabilizers
v) zone of thrust
what are the three curses of living in a ‘giving medium’?
yaw, pitch and roll
which fins are the least specialized? how do they aid?
dorsal and anal, forward motion, braking, stabilizers
the dorsal fin lies over what?
the centre of gravity
what is an anal fin’s main job?
to act as a stabilizer
what is the caudal fin’s main job?
organ of thrust
what is a dorsal fin’s main job?
lies above the centre of gravity, functions as a dorsal keel to prevent rolling
what are paired fins main job?
they serve as rudders to control vertical position.
the evolution changing of position of pectoral fins have provided which new capabilities?
i) maintain a stationary position in the watter by fanning the pectorals
ii) ability to clap the extended pectorals sharply back to accelerate rapidly
how is it possible that evolutionary changes occured in fin placement and function?
with the evolution of the swim bladder.
