Observation

The performance of candidates in this question was relatively good. Although majority of them could not satisfactorily state the difference between tactic and nastic movements in plants. Some candidates wrote that tactic movement is a response to directional stimuli.

In (b), candidates could give the examples of organisms that show tactic movement and nastic movement.

Questions (c)(i) and (ii) were well answered.

In (d), candidates did not give satisfactory answers. Some even wrote that high temperature leads to death of organisms.

Questions (e)(i) and (ii) were well answered.

Majority of candidates could not explain how fingerprinting can be used in crime detection.

 

The expected answers are:

 

(a) Differences between tactic and nastic movements in plants

Tactic movement	Nastic movement
Movement of whole organism/entire plant	movement shown by part of a plant;
Movement is directly towards/away from stimulus	non-directional movement;
Stimuli consist of light/heat/chemical	stimulus is touch/tugor pressure.

NB: points must correspond to score

 

(b) Examples of organisms that show

      (i) Tactic movement

Volvox; Chlamydomonas; Euglena, earthworm, Tilapia, and any other correctly named example.

 

      (ii) Nastic movement

Morning glory; Mimosa; Pride of Barbados (Caesalpinia); Four-o-clock plant; Morning flower, sunflower, Desmodium, clover and any other correctly named example.     

NB: Spellings must be correct to score in b (i and ii).      

(c) (i) Care of the skin

• - Eating balanced diet rich in vitamins A/B₂/E
• - Engaging in regular exercise;
• - Washing the skin with clean water and soap daily;
• - Drinking lots of water;
• - Moisturising/putting/rubbing the skin with lotion/cream;
• - Avoiding excessive exposure to ultraviolet rays/radiation;
• - Avoiding bleaching creams/harsh chemicals;
• - Wearing clean clothes next to skin;
• - Protect the skin against injury.                                            

 

(ii) Stimuli to which the mammalian skin is sensitive

• - Touch;
• - Pressure;
• - Heat;
• - Cold;
• - Pain;
• - Chemicals.                                                                                      

 

(d) Effects of high a temperature on/terrestrial habitat

• - Causes high transpiration rate in plants;
• - Plants wither/wilt;
• - Leads to high rate of metabolism in both plants and animals;
• - There is a high rate of decay of organic matter;
• - Leads to high rate of growth; and shorter length of life cycle in toad/housefly;
• - Makes poikilothermic animals to look for shelter from heat/hibernation;
• - There is high rate of water loss in animals/ sweating/perspiration;
• - Leads to high incidence of bush fires.                                

 

 (e) (i) Courtship behaviour in animals

A type of behaviour/instinctive action in animals; that play an important role in attracting a compatible mate/opposite sex; of the same species; for copulation/sexual reproduction.

 

 (ii) Courtship behaviours in animals

• - Pairing;
• - Territoriality;
• - Seasonal migration;
• - Smell/release of attractive sex hormones/odour;
• - Display of prominent colour patterns;
• - Mating calls/croaking/vocal display/sound signal;
• - Dancing/attractive movements.                                       

 

(f) Examples of organisms that carry out holozoic mode of nutrition

Goat; rat; lizard; frog; bird; human; any correctly named example; pitcher plants; sundew; bladder worms.                                                                                   

 

(g) Use of fingerprinting in crime detection

No two individuals have the same/identical pattern/contour of fingerprints/ hence it is used for crime detection; fingerprints left behind by a criminal at the scene of a crime/door/table/weapon/on victim; provide a valuable clue in the detection and subsequent arrest of a criminal; the fingerprints left on the scene of crime are photographed and the crime suspect’s fingerprints are taken and compared with the fingerprint at the scene of crime; if it matches then the suspect is the criminal.