The human skeleton

BIOLOGY

1

a) Explain how support in plants is achieved

 Turgor pressure due to absorption of water keeps cells firm hence hold herbaceous plants
upright
 collenchyma and clerenchyma tissues are closely packed in stem and roots to provide support
 inelastic cuticle on epidermis is covered by a waxy layer hence keeping shape of plant and
setting inward pressure against turgid cells and this causes a force to hold plant upright
 xylem vessels and tracheids are lignified to provide support to stems, roots and leaves
 climbing plants obtain mechanical support from other plants and objects
 they have climbing structures like tendrils which hold on to other objects

b) Give the reasons why support is necessary in animals
 For attachment of muscles
 For attachment of other body organs
 To protect delicate body organs
 To maintain body shape/form
 To enable movement/locomotion

c) Why is movement necessary in animals?
 Enables animals to search for food
 Enables animals to search for shelter
 Enables animals to escape predators/harmful conditions
 Enables animals to Search for water
 Enables animals to search for mates
 Enables animals to search for breeding sites

d) i) Name the organ used for support by animals

- Skeleton

ii) Name the different types of skeletons in animals, giving an example of an animal for
each type of skeleton named

 exoskeleton e.g. arthropoda (crab, insect)
 endoskeleton e. g. chordata (cat, fish)

iii) State the difference between exoskeleton and endoskeleton

 endoskeleton is a rigid framework covered by body tissues of an animal

,  exoskeleton is a rigid framework found on the surface of an animal

iv) State the advantages of having an exoskeleton

 supports/protects delicate inner parts
 water proof/prevents drying up of body
 provided surface for muscle attachment

v) Explain the importance of having an endoskeleton

 support the body
 give body its shape
 protect delicate organs e. g. skull, brain, ribs
 used in locomotion e.g. bones serve as levers
 red blood cells are formed in bone marrow
 minerals are stored in bones e. g. calcium and phosphorus

e) i) Explain how a fish is adapted to living in Water

 streamlined body for easy movement in water
 swim bladder controls depth of swimming
 fins for movement, balance, direction and stability,
 gills for gaseous exchange in water
 presence of lateral line to sense vibrations
 scales provide protection.
 colour which offers camouflage against predators

ii) Explain how a finned fish is adapted, to locomotion in Water

 streamlined body to reduce resistance/friction) to swim smoothly)
 the vertebral column consists of a series of vertebrae held together loosely so that it is flexible
 myotomes/muscles associated with vertebral column produce movement
 the sideways and backwards thrust of the tail and body against water results in resistance of
water pushing the fish sideways and forwards in a direction opposed to thrust
 heat not flexible so as to maintain forward thrust
 presence of fins helps in propulsion/balance/paired fins (pectoral and pelvic) for controlling
pitch and slow down movement/unpaired fins (dorsal, ventral, anal) for yawing and rolling
(caudal) for swimming/propulsion and steering/change of direction
 presence of swim bladder to make fish buoyant
 scales tip towards the back to provide smooth surface
 body covered with mucus to reduce friction
 flattened surface for easy floating

f) i) Name the main parts of the vertebral column giving the types of bones found in each
part