principles of locomotion

Question 1

engine

Answer 1

muscles

Question 2

transmission

Answer 2

bones as lever

Question 3

propeller

Answer 3

body surface against environment (ie hoof, wings, feet, etc)

Question 4

wheels vs limbs

Answer 4

• Wheels:
• More efficient
• Constant kinetic energy in one direction
• Limbs
• Require protraction and retractions (forwards and backwards movement) (we only apply these words to an entire limb whereas extension and flexion are applied to specific joints)
• Wastes energy
• But better over rough ground, can vary diameter and better shock absorption

Question 5

reptiles limbs

Answer 5

• Limbs stuck out transversely
• Great stability

Question 6

mammal limbs

Answer 6

• Limbs in vertical plane
• Intrinsic joints all same plan
• Lacks static stability
• Dynamic stability; we adjust muscle tension in limbs to keep balance
• Need good, fast nervous coordination

Question 7

shoulder of reptiles and birds (pectoral girdle)

Answer 7

• Forelimb connected to body coracoid bone → sternum
• Scapula does not move
• Glenoid points lateral

Question 8

shoulder of domestic mammals (pectoral girdle)

Answer 8

• Forelimb has no bony - connection to body (but clavicle in some mammals)
• Scapula moves
• Glenoid points down

Question 9

what limb structure does dino seem to have

Answer 9

mammalian limb structure with vertical arrangement of joints, so may have been warm blooded to maintain this dynamic stability and movement

Question 10

what does pectoral girdle in domestic animals consist of

Answer 10

• Only scapula
• Coracoid fused to it
• Clavicle reduced to a tendon

Question 11

functions of pectoral girdle in domestic mammals (shoulder)

Answer 11

• Transmits weight of body to limbs via the serratus ventralis (medial to scapula)
• Transmit muscle forces for propulsion

Question 12

what is shoulder girdle held by in domestic animals

Answer 12

synsarcosis (an alliance of muscles)

Question 13

Graviportal limbs

Answer 13

• Weight bearing, seen in heavy animals like elephant and rhinos
• Bones; short and thick
• Resist compression

Question 14

Cursorial limbs

Answer 14

• Adapted for running; ex dogs and horse
• Bones; long and thin
• Extensible struts
• Longer limbs are faster; more ground covered with each stride
• Reduction of foot in contact with ground
• Getting up on toes increases length of leg
• Reduction in number of digits
• Feet are light and so less energy to move
• Reduction in muscles of carpus and tarsus
• Lightens legs
• Lengthening of foot effectively means carpus and tarsus higher up as well
• Progressively more specialized → potential biomechanical problems
• Reduction of digits and long limbs → problems of support, balance and stability
• Alternating gait helps maintain stability
• Also need good dynamic stability; this also enables more feed to be off ground at any time → greater speed of movement

Question 15

Plantigrade

Answer 15

Whole foot in contact with ground (carpals/ tarsals, metacarpals/ metatarsals and digits)

Question 16

Digitigrade

Answer 16

Only distal end of metacarpals/ metatarsals and digits in contact with ground

Question 17

Unguligrade

Answer 17

On distal end of digit in contact with ground