Observation

Some candidates were able to state the habitats of specimens S (toad), U (lizard) and W (locust) while majority could not state the specific habitats of the organisms.  Some candidates could write the class

of the specimens but many of them started the spelling with small letters e.g amphibia, reptilia and insecta; and some even got the spelling wrong.

 

Many candidates were able to state the observable similarities and differences between specimens S (toad) and U (lizard).

 

Many candidates could state observable differences and similarities between specimens S (toad) and U (lizard) and some answers to the differences could not correlate.

 

Many students were able to identify the sex of specimen U (lizard) with reasons.

 

Most of the candidates that did not score well in this question could not state the external features with the function of the features.

 

Majority of the candidates were able to answer 4(e) satisfactorily but some candidates drew the arrow in the opposite direction, hence losing the mark for correct arrow.

 

The expected answers are:

• (a)  (i) Habitats of Specimens S/Toad, U/Lizard and W/Locust

Specimen S: Wet/moist/damp land/under stone/damp grass/vegetation near freshwater ponds.

Specimen U: walls/cracks/mountain slopes

Specimen W: vegetation/ grassland/farm.                                                   

 

      (ii) Class to which Specimens S, U and W belong

Specimen S: Amphibia

Specimen U: Reptilia

Specimen W: Insecta 

                                                                                  

(b) (i) Observable similarities in Specimens S and U

            Both have

• eyes;                                  -     (wide terminal) mouth;
• head;                                 -     2 pairs/ 4 limbs/forelimb/hindlimb;
• nostrils                               -     tympanic membrane/eardrum/ear drum;
• trunk.                                                                                            

 

     (ii) Observable differences between Specimens S and U

• - Specimen S/Toad has poison gland, but poison gland is absent in Specimen U/Lizard;
• - Gular fold absent in Specimen S/Toad but Gular fold is present in Specimen U/Lizard;
• - Presence of bulging eyes in Specimen S/Toad, eyes are not bulgimg in Specimen U/Lizard;
• - Scales absent in Specimen S/Toad, but scales present in Specimen U/Lizard;
• - Streamlined body in Specimen S/Toad, body not streamlined in Specimen U/Lizard;
• - Warty skin on Specimen S/Toad but no warts on Specimen U/Lizard;
• - Absence of tail in Specimen S/Toad but tail present in Specimen U/Lizard;
• - Absence of nuchal crest in Specimen S/Toad but nuchal crest is present in Specimen U/Lizard;
• - Neck absent in in Specimen S/Toad but present in Specimen U/Lizard;
• - Digits of hind limbs of Specimen S/Toad are webbed, but not webbed in Specimen U/Lizard;
• - No claws on the digits of Specimen S/ Toad but digits of Specimen U/Lizard end in claws;
• - In Specimen S/Toad the forelimbs end in four digits, but in Specimen U/Lizard the forelimbs end in five digits;
• - Body is short and wide in Specimen S/Toad but long and narrow in Specimen U/Lizard.

 

(c) (i) Sex of specimen U

Male                                                                                                   

     (ii) Reasons for the answer in 4 (c) (i)

• - Brightly coloured with red head/blue black trunk;
• - Blue and orange tail;
• - Presence of Gular fold
• - Prominent Nuchal crest.                                                                    

(d) Observable features that adapt specimen S to its habitat

• - Poison gland; for protection;
• - Warty skin; for camouflage;
• - Webbed digits of hind limbs for swimming;
• - Bulging eyes; for wide vision;
• - Muscular forelimbs; for absorbing shock;
• - Long muscular hind limbs for jumping/hopping
• - Cryptic colouration for camouflage;
• - Moist skin for (cutaneous) respiration.

NB: Structure and function must correspond to score.                      

 

(e) Food chain

            Specimen T/grass                    Specimen W/Locust                Specimen S/Toad;

            Specimen T/grass                    Specimen W/Locust                Specimen U/Lizard.

            Correct sequence         x1 each

            Correct arrow              x1 mark