- i) What is support?
- to support is to carry part of the weight/mass of an organism
ii) What is locomotion?
- progressive change in the position of an organism
iii) State the importance of support systems in living organisms
- they provide a framework for the body of organisms and help to determine their shape
- provide land animals with means for support to their weights against gravity
- organs are attached to the skeleton for support and stability to avoid entanglement and crushing each other
- they protect very important and delicate organs whether inside or outside the body e.g. eyes, heart
- in large plants the rigid trunks of trees support the greater mass of leaves and fruits
iv) State the importance of locomotion in animals
- in search of food
- search for mates
- escaping predators
b) i) Name the tissues in higher plants that provide mechanical support
- sclerenchyma
- collenchyma (not lignified)
- xylem/tracheids and vessels
ii) State the importance of support in plants
- exposing the surface area of leaf to sunlight for photosynthesis
- ensure flowers are exposed to pollination agents
- expose fruits and seeds to agents of dispersal
- to resist breakages due to their own weight and that of other organisms
- for proper transport and translocation of materials
iii) Name the types of plant stems
- herbaceous e.g. shrubs
- woody e.g. trees
- weak stems in creepers, twining plants and plants bearing tendrils
iv) Name the tissues in plants that are strengthened with lignin
- sclerenchyma
- xylem vessels/tracheids/xylem
v) What makes young herbaceous plants remain upright?
- turgidity
- presence of collenchyma
vi) State the ways by which plants compensate for lack of ability to move from one place to another
- ability to pollinate
- response to nastic and tropic movement
- ability to exploit localized nutrients
- ability to disperse seed or fruit propagation
c) i) Explain the ways in which erect posture is maintained in a weak herbaceous stem
– This is the function of turgidity and presence of collencyma
Cells take in water and become turgid
ii) 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
d) i) 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
ii) 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
e) 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
f) 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 help 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 flo
