Describe briefly the locomotion mechanisms in animals

Movement and Locomotion

14.3

Movement and Locomotion

Actions between skeletal muscles and bones at joint causing movement
Movements of arm and leg are due to the actions of antagonistic pair of skeletal muscle

Movements of arm:

Bending of the arm		Straightening of the arm
Biceps contracts, triceps relax	Action of muscles	Triceps contracts, biceps relax
Transmits pulling force exerted by biceps to the radius	Tendon	Transmits pulling force exerted by triceps to the ulna
Radius is pulled upwards	Bone	The ulna is pulled downwards
Holds bones together to form a joint	Ligament	Holds bones together to form a joint
forearm moves upwards to bend the arm	Joint	The forearm moves downwards to straighten the arm

Movements of leg:

Bending of the leg		Straightening of the leg
Biceps femoris contracts and quadriceps relaxes	Action of muscles	Quadriceps contract and biceps femoris relaxes
Transmits pulling force exerted by biceps femoris to tibia and fibula	Tendon	Transmits pulling force exerted by quadriceps to tibia
Tibia and fibula are pulled backward	Bone	Tibia and fibula are pulled forward
The leg is bent at knee joint	Joint	The leg is straightened

Locomotions in Animals:

Locomotion in earthworm

Characteristics

Has antagonistic muscles: circular muscle, longitudinal muscle.
Hydrostatic skeleton: contraction and relaxation of antagonistic muscles raise hydrostatic pressure of the fluid in the coelom
Chaetae: fine hooks which anchor to the ground

Mechanism of location and functions

Posterior chaetae anchor the ground. Circular muscles in the anterior contract and the longitudinal muscles relax, producing high hydrostatic pressure. These cause the anterior segment to extend forward
Anterior chaetae anchor the ground. Posterior chaetae are withdrawn. Circular muscles in the anterior relax and longitudinal muscles contract, producing low hydrostatic pressure. These cause the posterior segments to be pulled forward
Continuos process - Peristaltic waves enable earthworms to move forward

Locomotion in fish

Characteristics

Scaly and slimly body to reduce water resistance
W-shaped antagonistic muscle blocks are arranged in segments on both sides of a vertebral column named myotomes
Swim bladder: an air sac inside the abdomen to maintain buoyancy
Dorsal and ventral fins - prevent yawning and rolling
Tail fin - forward thrust
Paired fin (pelvic and pectoral fins) - steering, prevent pitching

Mechanism of locomotion and function

Right myotomes contract, left myotomes to relax
Head and tail will bend to the right
Right myotomes relax, left myotomes contract
Head and tail will bend to the left
Continuous contraction and relaxation of muscles allow fish to move their tail
The tail movement creates a forward thrust

Locomotion in grasshopper:

Characteristics

Antagonistic muscles:

Flexor muscles
Extensor muscles:

Found inside the internal structure of the exoskeleton
The hind legs are bigger and longer for jumping
Movement is produced by contraction and relaxation of these muscles

Mechanism of locomotion and function

Jumping:

At rest, flexor muscles contract, hind legs folded in the shape of "Z"
Extensor muscles contract and hind legs straighten
Grasshopper jumps forward and upwards

Movement and Locomotion

14.3

Movement and Locomotion

Actions between skeletal muscles and bones at joint causing movement
Movements of arm and leg are due to the actions of antagonistic pair of skeletal muscle

Movements of arm:

Bending of the arm		Straightening of the arm
Biceps contracts, triceps relax	Action of muscles	Triceps contracts, biceps relax
Transmits pulling force exerted by biceps to the radius	Tendon	Transmits pulling force exerted by triceps to the ulna
Radius is pulled upwards	Bone	The ulna is pulled downwards
Holds bones together to form a joint	Ligament	Holds bones together to form a joint
forearm moves upwards to bend the arm	Joint	The forearm moves downwards to straighten the arm

Movements of leg:

Bending of the leg		Straightening of the leg
Biceps femoris contracts and quadriceps relaxes	Action of muscles	Quadriceps contract and biceps femoris relaxes
Transmits pulling force exerted by biceps femoris to tibia and fibula	Tendon	Transmits pulling force exerted by quadriceps to tibia
Tibia and fibula are pulled backward	Bone	Tibia and fibula are pulled forward
The leg is bent at knee joint	Joint	The leg is straightened

Locomotions in Animals:

Locomotion in earthworm

Characteristics

Has antagonistic muscles: circular muscle, longitudinal muscle.
Hydrostatic skeleton: contraction and relaxation of antagonistic muscles raise hydrostatic pressure of the fluid in the coelom
Chaetae: fine hooks which anchor to the ground

Mechanism of location and functions

Posterior chaetae anchor the ground. Circular muscles in the anterior contract and the longitudinal muscles relax, producing high hydrostatic pressure. These cause the anterior segment to extend forward
Anterior chaetae anchor the ground. Posterior chaetae are withdrawn. Circular muscles in the anterior relax and longitudinal muscles contract, producing low hydrostatic pressure. These cause the posterior segments to be pulled forward
Continuos process - Peristaltic waves enable earthworms to move forward

Locomotion in fish

Characteristics

Scaly and slimly body to reduce water resistance
W-shaped antagonistic muscle blocks are arranged in segments on both sides of a vertebral column named myotomes
Swim bladder: an air sac inside the abdomen to maintain buoyancy
Dorsal and ventral fins - prevent yawning and rolling
Tail fin - forward thrust
Paired fin (pelvic and pectoral fins) - steering, prevent pitching

Mechanism of locomotion and function

Right myotomes contract, left myotomes to relax
Head and tail will bend to the right
Right myotomes relax, left myotomes contract
Head and tail will bend to the left
Continuous contraction and relaxation of muscles allow fish to move their tail
The tail movement creates a forward thrust

Locomotion in grasshopper:

Characteristics

Antagonistic muscles:

Flexor muscles
Extensor muscles:

Found inside the internal structure of the exoskeleton
The hind legs are bigger and longer for jumping
Movement is produced by contraction and relaxation of these muscles

Mechanism of locomotion and function

Jumping:

At rest, flexor muscles contract, hind legs folded in the shape of "Z"
Extensor muscles contract and hind legs straighten
Grasshopper jumps forward and upwards

Movement and Locomotion

Movement and Locomotion

Chapter : Support and Locomotion in Humans and Animals

Topic : Describe briefly the locomotion mechanisms in animals

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