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Chapter 2Locomotion and Support

2.1 SUPPORT AND

LOCOMOTION IN

HUMANS AND ANIMALS

2.1 Support and Locomotion in

Humans and Animals Importance of support and locomotion

◦ Search for food

◦ Provide protection by escaping from enemies

or avoiding danger

◦ Search for more conducive living environment

◦ Find mates for reproduction

◦ Avoid overcrowding which enables the

offspring to move to another place


Humans and Animals (cont’d)

Human skeletal system

◦ Consist of two main part; axial skeleton and

appendicular skeleton

Human

skeleton

Parts

Axial skeleton 1. Skull

2. Vertebral column

(the backbone)

3. Ribcage

Cranium, bones of the face, jaw

Cervical vertebrae, thoracic vertebrae,

lumbar vertebrae, sacrum, coccyx

Sternum and ribs

Appendicular

skeleton

1. Pectoral girdle

2. Arm (forelimbs)

3. Pelvic girdle

4. Leg (hind limbs)

Scapula and clavicle

Humerus, ulna, radius, carpals,

metacarpals, phalanges

Ischium, pubis, ischium

Femur, tibia, fibula, tarsals, metatarsals.

phalanges


Humans and Animals (cont’d) Skull

◦ Cranium – enclose and

protect the brain

◦ Facial bones and jaw

Protect the eyes and ears

Upper jaw is fixed

◦ Skull is joined to the

vertebral column at the base

of cranium



Rib

◦ Twelve pairs of ribs

Articulate with thoracic cavity

dorsally, and sternum ventrally

◦ Sternum is the front part


Humans and Animals (cont’d) Vertebral column

◦ Consists of 33 vertebrae, joined but separated

by discs of cartilage

◦ Five types of vertebrae

1. Cervical vertebrae (7)

2. Thoracic vertebrae (12)

3. Lumbar vertebrae (5)

4. Sacral vertebrae (5)

5. Coccyx



Centrum

Gives support

Neural arch

Forms neural

canal

Neural spine

Muscle

attachment

Neural canal

Protects spinal

cord


Humans and Animals (cont’d) Support head and

neck

Sentrum is short

and thick

Large and thick

sentrum


Humans and Animals (cont’d) Appendicular skeleton

◦ Consists of

1. Pectoral girdles and forelimbs (arms)

2. Pelvic girdle and hind limbs (legs)


Humans and Animals (cont’d) Arms


Humans and Animals (cont’d) Legs

Pelvic

girdle


Humans and Animals (cont’d) Joints

◦ Place where two bones

meet

◦ Bones are held together by

ligaments

◦ Sinovial joints – joints

that contains a cavity filled

with fluid

◦ End of bones are covered

with cartilage.


Humans and Animals (cont’d) Joints

◦ Various types of joints

1. Hinge joint Allow movement in one plane

2. Ball-and-socket joint Allow movement in all directions


Humans and Animals (cont’d) Movement in a limb

◦ Skeletal muscles are attached to bones by tendons.

◦ Movements of cause by antagonistic movement of muscles: One muscles is contracted, another is relaxed


Humans and Animals (cont’d) Structure of a muscle

◦ Muscle fibre – single, long cylindrical cell that contains many nuclei

◦ Myofibrils – smaller units that made up muscle fiber

◦ Interaction of actin and myosin will cause muscle contraction


Humans and Animals (cont’d) Locomotion of earthworm

◦ Earthworms have a hydrostatic skeleton (the force of contraction is applied to a coelum(fluid filled chamber).

◦ Coelom is surrounded by two antagonistic muscle circular muscles – surround the chamber

longitudinal muscles – extend from one end to the other.

◦ Thinner and longer: When circular muscle contract and the longitudinal muscle relax. (and vice verca)

◦ The muscles contract rhythmically to produce peristaltic waves which begins at the front and move towards the end of the body.

◦ Earthworm has chaetae (bristles) which anchor parts of the body to the ground so that other parts can be pulled towards it.


Humans and Animals (cont’d) Locomotion of grasshopper

◦ The flexor and extensor (antagonistic) muscles are attached to the internal surface of the exoskeleton.

◦ Flexor muscles bend a joint.

◦ Extensor muscles straighten it.

◦ The rear legs of a grasshopper are long and muscular and is adapted for hopping.

◦ Sitting position: When the flexor muscle contracts, the lower leg is pulled towards the body. The hind leg is folded in a Z shape and ready for a jump.

◦ Jump: When the extensor muscle contracts, the leg jerks backwards, propelling the grasshopper forward and upward into the air.



◦ The flexor and extensor (antagonistic) muscles are attached to the internal surface of the exoskeleton.

◦ Flexor muscles bend a joint.

◦ Extensor muscles straighten it.

◦ The rear legs of a grasshopper are long and muscular and is adapted for hopping.

◦ Sitting position: When the flexor muscle contracts, the lower leg is pulled towards the body. The hind leg is folded in a Z shape and ready for a jump.

◦ Jump: When the extensor muscle contracts, the leg jerks backwards, propelling the grasshopper forward and upward into the air.


Humans and Animals (cont’d) Locomotion of fish

◦ Fish has streamlined body shape

◦ Scales that overlap one another, with free ends

pointing backwards to reduce friction

◦ Fish have W-shaped muscles called myotome



◦ Fish move forward

from the

contraction and

relaxation

(antagonistic) of

myotome on either

side of the body



◦ Function of fins in fish – balance the body

◦ Pectoral fins – for steering

◦ Pelvic fins – for balance, to prevent diving and

rolling


Humans and Animals (cont’d) Locomotion of bird

◦ Bird can fly either by flapping their wings or

gliding



◦ When wings move down Pectoralis major contracts

Wings are pulled down

◦ When wings move up

Pectoralis minor contracts



◦ During gliding, wings

are spread – act as

aerofoil

◦ Bernoulli principle –

provide upward

thrust

2.3 SUPPORT SYSTEM IN PLANTS

2.3 Support Systems in Plants

Support in plants is necessary to:

◦ Stay upright

◦ Obtain sufficient sunlight

◦ Bear the weight the plant

◦ Provide strength to withstand wind

ressistance


(cont’d)

Plants

Aquatic

Submerged Floating

Terrestrial

Herbaceous Woody


(cont’d) Submerged plants

◦ Hydrilla sp.

◦ Have thin, narrow and

flexible leaves – provide

little ressistance

◦ Air sacs inside the

leaves and stems - keep

the plant floating close

to the surface to obtain

maximum sunlight.


(cont’d)

Floating plants

◦ Lotus plant

◦ Have broad leaves that are firm but flexible

enough to resist tearing by wave action.

◦ Aerenchyma tissues (spongy tissues with large

air spaces between the cells) in the stems and

leaves provide buoyancy so that the plants can

float on the surface of the water


(cont’d) Herbaceous plant

◦ Support provided by the turgidity of the parenchyma and collenchyma cells.

◦ Turgor pressure of the fluid content in the central vacuole pushes the cell membrane and the cell contents against the cell wall, creating support for the stem, root and leaves.

◦ The thickening of the cell walls with cellulose and pectin in collenchyma cells provide additional mechanical strength


(cont’d) Woody plants

◦ Support provided through tissue

modification

◦ Xylem tissues

Strenghtened by lignin

Lignin – tough, not elastic and nor permeable

to water

◦ Parenchyma tissues

Store starch, sugars and water

It become turgid – give support


(cont’d) Woody plants

◦ Collenchyma tissues

Thickened with cellulose and pectin

◦ Sclerechyma tissues

Thickened with lignin

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