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54 Cards in this Set
- Front
- Back
In mammals we also see the incorporation of the ___ as a limb element. The sprawled posture by many amphibians and reptile requires a lot of energy to maintain and this is helped by having rigidly fixed ______ . In reptiles the scapula is attacted to the ____ by having a ____, _____, & _____.
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scapula; limb girdles; sternum; substantial coracoid, clavicle, and interclavicles
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In the permanent push up position, the ______has to be working constantly to adduct the formlimbs and keep the body up off the ground and so the chest has to form a rigid strut to transmit that force to the limbs.
In mammals, the limbs are rotated under the body, so the ________ is freed from this role as a strut for the adductors to work against |
pectoral musculature, pectoral girdle
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What is lost in the mammals?
In cursorial specialists, the _____ is lost or reduced (cursorial: adapted to or specialized for running) |
coracoid; clavicle
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For mammals the body is support by the connection of the scapula with the sternum. t or f
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False. The scapula now has NO bony connection with sternum and it supports the body by a MUSCULAR SLING
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What does the muscular sling mostly consist of?
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the serratus ventralis muscles, but is also supported by the rhomboids, trapezius, perctoralis groups
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Describe how the scapula location after it has been rotated in cursorial species
What is the result of the scapula being freed from its connection with the sternum and oriented in the direction of movement? |
The scapula is rotated in cursorial species so that the gleniod fossa points more ventrally and the blade of the scapula is in a parasagittal plane.
-it now begins to function as yet another limb segment |
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what is the purpose of incorporating flexion and extension of the vertebral column, as is seen particularly in felids such as the cheetah
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it is the final way of increasing the stride length
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The ability to incorporate ______ movements in the direction of travel is a benefit over the lateral undulations seen in reptile, which are _____ to the direction of travel
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spinal movements, perpendicular
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What is modified in the cheetahs to allow them to increase their stride length by up to 20%
how does this differ from ungulates, such as the hourse? |
modifications to the orientation of the ZYGAPOPHYSES
ungulates such as the hours tend to keep their trucks more rigid while running read paragraph 3 of pg 1 on lecture 14 terrestrial locomotion/locomotion in fluid |
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What is the cost associated with lengthening the limbs ?
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it becomes more energetically expensive to oscillate them
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We have been considering the forces to be point forces- applied in one single location. When dealing with a mass that is distributed throughout the lever, you have to consider a quantity called the ______.
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moment of inertia
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How do you compute moment of inertia, what is it equal to?
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computed by divided the limb into many small segments going from proximal to distal
equal to the mass of each segment X the square of the distance from that segment to the center of rotation . |
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Moment of inertia is = mass of each segment X the square of the distance from that segment to the center of rotation.
This means that the mass farther away from the center of rotation has a ______ effect on the moment of inertia, and makes it ______energically expensive to move the limb |
disproportionate effect; more energetically expensive
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lengthening the limbs comes at cost...its becomes more energetically expensive to oscillate them, how is this effect moderated?
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by making the distal limb segments as slender as possible while still being able to withstand the forces applied to them
*it is also minimized by the placement of muscles proximally, usually with long tendons running through the more distal segments |
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What is the energy exchange mechanism that is used in walking?
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inverted pendulum
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When humans walk, our center of mass is at its _____ point as we push off from the ground and begin the stance phase. The center of mass then rises as it vaults over a relatively stiff limb and reaches a ___ in the middle of the stance phase. It then falls again to its ___ point as we fall forward over the stance leg and land on the other foot.
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lower point; maximum; lowest point
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The speed is at its ____ as we push off from the ground and gradually ____ as we lift ourselves up against gravity, reaches its ____point in the middle of the stance phase, then _____again as we fall forward under gravity.
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greatest; decreases;lowest; increases
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because of gravitational potential energy (energy due to height) and kinetic energy ( energy due to speed) oscillate out of phase with one another, they are constantly _____as we walk, so that the energy provided by falling under gravity during the last half of stance is used to raise the center of mass during the first halt of the next stride, and the _____energy gained by this is converted back to ______energy as the center of mass falls again
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exchanged; gravitational potential energy; kinetic energy
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what is another means of reducing the energetic cost of locomotion during running?
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by storing energy in the elastic elements of the muscles and releasing it in the next propulsive cycle.
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Kangaroos reduce the energetic cost of locomotion by storing energy in the elastic elements of the muscles and releasing it in the next propulsive cycle.
(last paragraph on pg2) it has been found in hopping kangaroos that the energetic cost of hopping does not increase with increasing speed and that mothers that are carrying joeys also incur no increase in cost of locomotion. t or f |
true. it is all made up for by increasing the stretch in the tendons due to the greater landing impact, then using that stored energy to generate power.
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what are fluids?
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gases and liquids; they share properties not shared by solids
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unless the a force is great enough to fracture a solid, it will not always return to its original shape. t or f
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false; it will always return to its original shape
solids resist deformation PRINCIPLE OF ELASTICITY |
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fluids flow in response to applied forces. Do they resist the change in shape
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no
they do offer resistance, however, and we say that fluids resist the rate of deformation |
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____ still applies in fluid.
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newtons 2nd law
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In any kind of locomotion what two forces are required?
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vertical and horizontal
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In the case of terrestrial locomotion, what is the upward force used for?
what is the backward force used for? Swimming and flying animals, move through a 3 demential space _______a fluid medium that reacts in very different ways than a solid substrate |
upward force to resist the downward pull of gravity; backward force force to push the animal forward.
pushing against |
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Any swimming or flying animal will encounter resistance from the fluid they are in that tends to impede their forward progress. What is this force called
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drag
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Kangaroos reduce the energetic cost of locomotion by storing energy in the elastic elements of the muscles and releasing it in the next propulsive cycle.
(last paragraph on pg2) it has been found in hopping kangaroos that the energetic cost of hopping does not increase with increasing speed and that mothers that are carrying joeys also incur no increase in cost of locomotion. t or f |
true. it is all made up for by increasing the stretch in the tendons due to the greater landing impact, then using that stored energy to generate power.
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define drag
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a force that acts parallel and opposite the direction of travel
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what are fluids?
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gases and liquids; they share properties not shared by solids
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what force do animals generate to overcome the force of drag?
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thrust; a force that pushes the animal forward in the direction it is going
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unless the a force is great enough to fracture a solid, it will not always return to its original shape. t or f
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false; it will always return to its original shape
solids resist deformation PRINCIPLE OF ELASTICITY |
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fluids flow in response to applied forces. Do they resist the change in shape
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no
they do offer resistance, however, and we say that fluids resist the rate of deformation |
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____ still applies in fluid.
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newtons 2nd law
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In any kind of locomotion what two forces are required?
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vertical and horizontal
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In the case of terrestrial locomotion, what is the upward force used for?
what is the backward force used for? Swimming and flying animals, move through a 3 demential space _______a fluid medium that reacts in very different ways than a solid substrate |
upward force to resist the downward pull of gravity; backward force force to push the animal forward.
pushing against |
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Any swimming or flying animal will encounter resistance from the fluid they are in that tends to impede their forward progress. What is this force called
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drag
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define drag
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a force that acts parallel and opposite the direction of travel
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what force do animals generate to overcome the force of drag?
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thrust; a force that pushes the animal forward in the direction it is going
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What are the two possible upward forces
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buoyancy & Lift
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____is a force that results from the displacement of the fluid by the animal and depends on the difference in density between the fluid and the animals
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buoyancy
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buoyancy always acts ____with respect to the earth, regardless of the direction of travel by the animal
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vertically upward
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___ is a force perpendicular to the direction of travel
see aerodynamics definition |
lift
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that main downward for is ____and it always operates vertically downward with respect to the earth
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gravity
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In some cases, particularly with swimming birds and mammals, the buoyant force exceeds the gravitational force and to stay submerged they have to generate a force that pushes them downward. What is the force called
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downwardly-directed force
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what force tends to retard forward progress
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drag
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what are the two physical phenomena that cause drag?
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skin friction or friction drag & pressure drag
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Which form of drag results of the viscosity of the fluid
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skin friction
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which form of drag results from the disruption of the fluid as it is forced to separate and move around the animal as it moves through
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pressure drag
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define viscosity
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is the tendency for fluid molecules to want to stick together and do what their neighbors are doing.
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The more fluid disturbed, the _____the drag
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greater
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The fluid directly adjacent to the surface of the animal travels along the animal at the same velocity.
Whereas; fluid at the distance from the animal has zero velocity There is a region in between called the __________ where layers of fluid are being sheared past each other and cant move in the same was as their neighbors and generates resistance or drag This occurs over the entire area the animals exposed to the fluid, so its magnitude depends on the total surface area of the animal, ofter referred to as the ? |
boundary layer
wetted area |
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The second form of drag is called pressure drag because the disturbance causes a ____pressure anteriorly, where the molecules of the fluid collide with, and have to move around the front end, and a ____pressure behind where the space behind the object has been vacated because it is blocked by the object.
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high; low
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How is difference in pressure minimized ?
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streamlining; by streamlining so that the flow separates smoothly around the front end and tapers gradually posteriorly so there is minimal disruption to the fluid.
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