Lec 14

Question 1

Gravity

Answer 1

The pull of the Earth experienced by vertebrates

Question 2

Stability of a vertebrate body relies on

Answer 2

Limbs being strong enough to support the weight

Centre of gravity is above and within the polygon outlined by the limbs

Question 3

Body is stable so long as

Answer 3

Ground reaction forces is equal to the body weight

Question 4

Rigidity of a vertebrate body relies on tensions from

Answer 4

Muscles and tendons

Ligaments

Thicken bones

Other connective tissues

Question 5

Two examples showing muscles and ligament supports

Answer 5

Ligament is elastic structure similar to rubber bands that prevent the bones from moving too much (made primarily of type 1 collagen fibres)

Muscle on each side of the limb/join act together to stabilize joints

Question 6

Posture

Answer 6

A static stance, and the body is usually stable

Question 7

Gait

Answer 7

A dynamic sequence of stance, typically transitioning from one stance to another

Question 8

Sprawling

Answer 8

Considered plesiomorphic

Elbow joint is approximately 90 degrees

Stability during locomotion requires large adductor muscles under humerus

Typically involve undulation of the body during locomotion

Typically seen in squamates/urodelan

Question 9

Parasagittal

Answer 9

Considered derived

Limbs are positioned under trunk of the body

Adductor muscles under humerus is reduced

Body is somewhat steady during locomotion

Typically seen in therian mammals/birds

Question 10

Crocodilians can dynamically change between

Answer 10

Sprawling and parasagittal posture

Parasagittal is very energy expensive so they only use it to escape predators

Question 11

Two phases of step

Answer 11

Stance phase

Swing phase

Question 12

Stance phase

Answer 12

Limb contacts the ground and muscles contract to provide forward momentum

Question 13

Swing phase

Answer 13

Limb is lifted and move forwarf

Question 14

Energy of limb swing is lost to

Answer 14

Collision and friction with the ground

Question 15

Three situations requires additional work by the muscles

Answer 15

To accelerate rapidly

To climb vertically

Individuals with heavier bodies and limbs

Question 16

Three methods of studying gaits

Answer 16

High speed videos

Footprints

Kinematic stimulations

Question 17

Suction feeding and ram feeding

Answer 17

Not feasible on land, so food items are most often bitten

Question 18

To capture food, some tetrapods use

Answer 18

Muscular tongue or forelimbs to move food items into the mouth

Question 19

Various mechanisms to project muscular tongues evolved

Answer 19

Convergently in many clades of Tetrapoda