BIOD43H3 Lecture Notes - Lecture 3: Swim Bladder, Motor Unit, Motor Neuron
Tutorial 3:
Results:
• Positive relationship between speed and body mass
• Negative relationship between stride and body mass
• Mass-specific energy cost per stride was independent of body mass
1. While there are strong general relationships between variables like stride frequency at the
preferred trot or gallop speed and body size, there is some variation. What are some possible
causes of this variation? In other words, why might the stride frequency exhibited by a rat
when trotting at it preferred speed be considerably lower than the value for the regression
line?
• Anatomical, morphological differences explain this variation.
o Length of limbs in individuals are different
o Could be in terms of body fat, sex, etc.
• Crouch is different from spring: different animals spend more time in this position,
changing the speed e.g., rabbits
2. No trottig data is preseted for either chipuk studied. Why do you thik this is the
case? (Hint: think about the squirrels you see every day as you walk around campus)
• Chipuks do’t tpiall trot so trottig data is irreleat. Chipuks go fro alkig
straight to running/galloping, no transition.
o Range of speed is very small if they trot, not significant and not easy to measure
trotting
o Researchers used high-speed cameras to capture their movement
3. The authors state that they were unable to obtain data on the full range of galloping
speeds that each species is likely capable of. Even if they had been able to do this, why would
they likely have chosen not to include such data in this paper?
• If ou’re orkig at the aiu speed, the eerg used is aaeroi etaolis, e
want aerobic consumption
• Aerobic metabolism + Anaerobic metabolism -> cost?
o Need to calculate the cost taking into account both types of metabolism
4. Despite not having confidently measured the full range of galloping speeds in many of their
animals, the authors nonetheless examine the scaling of the very same stride characteristics
of the preferred gallopig speed (defied as the speed halfway between the observed
minimum and maximum gallop speed) they examined for the preferred trotting speed. How
do they defend their actions? Are there other stride characteristics that they would have
been wrong to include, given their uncertainty with respect to the collection of the full gallop
speed range? Why?
• Stride frequency changes relatively little throughout the range of the speeds throughout
the gallop.
o Galloping frequency is nearly independent of speed
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