Question 2
LIST OF SPECIMENS
Specimen A - Winged termite.
Specimen B - Maggot (freshly procured).
Specimen C - Adult butterfly with open wings.
Specimen D - Caterpillar (freshly procured).
Specimen E - Grasshopper.
Specimen F - Carrot with leaves attached (freshly procured).
Specimen G - Irish potato.
Specimen H - Adult mosquito.
Specimen J - Adult cockroach.
Specimen Q - Housefly.
Specimen R - Earthworm (dead, freshly procured in a Petri dish containing water).
Specimen S - cross section of unripe mango fruit.
Specimen T - Cross section of tomato fruit.
Study specimens F and G carefully and use them to answer questions 2(a) and 2(b).
- (a) State three observable features of biological importance in:
(i) specimen F; [3 marks]
(ii) specimen G. [3 marks] - (i) Classify specimens F and G as either stem tuber or root tuber. [2 marks]
(ii) Give two reasons each for the answers in 2(b)(i). [4 marks]
Study specimens H and J carefully and use them to answer questions 2(c) and 2(e).
- Classify specimens H and J into the class to which both belong. [1 mark]
- (i) State four observable differences between specimens H and J. [4 marks]
(ii) State four observable similarities between specimens H and J. [4 marks] - (i) State the feeding habits of each of specimens H and J. [2 marks]
(ii) Name two observable features used for feeding in specimen J. [2 marks]
Observation
This question was poorly attempted. Some candidates could not state the observable features of biological importance of specimen F. Some candidates could state the observable similarities between specimens H and J. Most candidates could not also state the feeding habits of specimen H but could state for specimen J.
The expected answers are:
- Observable features of biological importance in
Specimen F/Carrot
- Main root/tap root/swollen/root tuber;
- Presence of lateral roots;
- Presence of short stem (green);
- Presence of foliage leaves;
- Part of main root tapering.
Specimen G/Irish potato
- Swollen stem/stem tuber;
- Bud(s)/eye;
- Lenticels;
- Scale leaf
- Adventitious root(s).
- (i) Classification of
Specimen F/Carrot
Root tuberSpecimen G/Irish potato
Stem tuber(ii)Reasons for classificationSpecimen F/Carrot
- Swollen tap root;
- Lateral roots present;
- Has a reduced stem (above the swollen tap root).
Specimen G/Irish potato- Swollen stem/tuber;
- presence of bud(s)/eye;
- presence of scale leaves/leaf;
- presence of lenticel(s).
- Class of specimens H and J
Insecta - (i) Observable differences between specimens H and J
(ii) Similarities between specimens H/adult mosquito and J/adult cockroach
- Presence of a pair of compound eyes;
- Body is divided into three divisions/head, thorax and abdomen;
- Three pairs of/six (walking) legs;
- Presence of jointed appendages;
- Presence of a pair of membraneous wings;
- Presence of a pair of antennae;
- Both have exoskeleton made of chitin;
- Segmented body.
(i)Feeding habit of
Specimen H/adult mosquito
Piercing and suckingSpecimen J/adult cockroach
Biting and chewing(ii)Observable features used for feeding in specimen J/adult cockroach
Mandible; maxillae; labium; labrum