WAEC SSCE - Biology - 2011 (Practical)
Pregunta 1 Informe
Carefully study specimens J and K and answer questions 4(a) to 4(d).
(a) Name the type of refuse in specimens: (i) J (ii) K.
(b) List three animal vectors of disease causing organisms that breed on a each of specimens J ana K.
(ii) Name four diseases each caused by animal vectors associated with each or specimen J and K.
(c) Name one method of disposal of each of specimens J and K in: (i) rural areas (ii) urban areas.
(d)(i)State four effects of improper disposal of specimen K
(ii) In a tabular form. state five differences between specimens J and K.
(iii) outline one way in which specimen J is of importance to farmers.
(a) Type of refuse: (i) Specimen J is dry refuse (solid waste). (ii) Specimen K is wet refuse (sewage / liquid waste).
(b)(i) Three animal vectors that breed on each: On J - housefly, cockroach and rat. On K - housefly, mosquito (female Anopheles or Aedes) and snail.
(b)(ii) Four diseases spread by the vectors of each: Associated with J - typhoid, cholera, dysentery and diarrhoea. Associated with K - malaria, yellow fever, bilharzia (schistosomiasis) and elephantiasis.
(c) One method of disposal of each:
(i) Rural areas - J: refuse dump / burying / composting; K: pit latrine / soakaway pit.
(ii) Urban areas - J: sanitary landfill / incineration; K: septic tank and sewage treatment.
(d)(i) Four effects of improper disposal of specimen K (sewage): contamination of water bodies (water pollution); offensive odour; source and spread of diseases; pollution of the soil.
(d)(ii) Five differences between specimens J and K:
| Specimen J (dry refuse) | Specimen K (wet refuse / sewage) |
|---|---|
| Dry solid waste | Wet liquid waste |
| Contains little or no water | Contains a large proportion of water |
| Can be kept for a long period | Cannot be kept for long |
| Can be burnt | Cannot be burnt |
| Can be compacted / compressed | Cannot be compacted |
(d)(iii) One way specimen J is of importance to farmers: when buried or composted it decays into organic manure that enriches the soil and improves its fertility.
Detalles de la respuesta
(a) Type of refuse: (i) Specimen J is dry refuse (solid waste). (ii) Specimen K is wet refuse (sewage / liquid waste).
(b)(i) Three animal vectors that breed on each: On J - housefly, cockroach and rat. On K - housefly, mosquito (female Anopheles or Aedes) and snail.
(b)(ii) Four diseases spread by the vectors of each: Associated with J - typhoid, cholera, dysentery and diarrhoea. Associated with K - malaria, yellow fever, bilharzia (schistosomiasis) and elephantiasis.
(c) One method of disposal of each:
(i) Rural areas - J: refuse dump / burying / composting; K: pit latrine / soakaway pit.
(ii) Urban areas - J: sanitary landfill / incineration; K: septic tank and sewage treatment.
(d)(i) Four effects of improper disposal of specimen K (sewage): contamination of water bodies (water pollution); offensive odour; source and spread of diseases; pollution of the soil.
(d)(ii) Five differences between specimens J and K:
| Specimen J (dry refuse) | Specimen K (wet refuse / sewage) |
|---|---|
| Dry solid waste | Wet liquid waste |
| Contains little or no water | Contains a large proportion of water |
| Can be kept for a long period | Cannot be kept for long |
| Can be burnt | Cannot be burnt |
| Can be compacted / compressed | Cannot be compacted |
(d)(iii) One way specimen J is of importance to farmers: when buried or composted it decays into organic manure that enriches the soil and improves its fertility.
Pregunta 2 Informe
Study carefully specimen E and F and use them to answer questions 2(a) to 2(d).
(a) (i) What class of organism do specimen E and F belong to?
(ii) State three similarities between specimen E and F.
(iii) In a tabular form, state three differences between specimens E and F;
(b) State two ways each in which: (i) Specimen E (ii) Specimen F are of economic importance.
(C)(i) State one observable feature each of specimens E and F and how these features adapt the specimens against predation.
(ii) Name the habitats of specimens E and F.
(d) Remove all the wings of specimen E. Make a drawing 8-10 cm long of the dorsal view of specimen E and label fully.
(a)(i) Class of organism: Specimens E and F both belong to Class Insecta.
(a)(ii) Three similarities between specimen E and F:
- Both have three pairs of jointed legs (six legs).
- Both have the body divided into head, thorax and abdomen (segmented body) and possess a pair of antennae with mandibulate (biting) mouthparts.
- Both are bilaterally symmetrical with jointed appendages.
(a)(iii) Three differences between specimens E and F:
| Specimen E (Cockroach) | Specimen F (Soldier termite) |
|---|---|
| Head small relative to the body | Head large relative to the body |
| Wings present | Wings absent |
| Compound eyes present (has sight) | No eyes (blind) |
| Dark brown colour; small mandibles | Light brown colour; large mandibles |
(b) Economic importance
(i) Specimen E (cockroach): destroys clothes, books and stored materials; contaminates food, reduces its quality and gives it a foul odour; serves as a vector (carrier) of disease-causing organisms.
(ii) Specimen F (soldier termite): speeds up decay by breaking down dead wood into humus, which increases soil fertility and improves soil drainage and aeration through its channels; it is a source of protein for poultry feed, and mud from the termitarium is used for building; however, it also destroys wood in roofs, houses, furniture, timber and crops.
(c)(i) Observable feature adapting each specimen against predation:
- Specimen E (cockroach): its dorso-ventrally flattened body lets it hide quickly in cracks and crevices, and its brown colour blends with the surroundings as camouflage; its wings also allow it to fly away from predators.
- Specimen F (soldier termite): its large, strong mandibles are used to bite in defence, and the snout-like projection of the head produces a poisonous defensive secretion for protection.
(c)(ii) Habitats: Specimen E (cockroach) lives in dark boxes, cupboards and cesspits; Specimen F (soldier termite) lives in the termitarium (termite mound/hill).
(d) Drawing of the dorsal view of Specimen E (cockroach) with all wings removed, 8-10 cm long, fully labelled:
Detalles de la respuesta
(a)(i) Class of organism: Specimens E and F both belong to Class Insecta.
(a)(ii) Three similarities between specimen E and F:
- Both have three pairs of jointed legs (six legs).
- Both have the body divided into head, thorax and abdomen (segmented body) and possess a pair of antennae with mandibulate (biting) mouthparts.
- Both are bilaterally symmetrical with jointed appendages.
(a)(iii) Three differences between specimens E and F:
| Specimen E (Cockroach) | Specimen F (Soldier termite) |
|---|---|
| Head small relative to the body | Head large relative to the body |
| Wings present | Wings absent |
| Compound eyes present (has sight) | No eyes (blind) |
| Dark brown colour; small mandibles | Light brown colour; large mandibles |
(b) Economic importance
(i) Specimen E (cockroach): destroys clothes, books and stored materials; contaminates food, reduces its quality and gives it a foul odour; serves as a vector (carrier) of disease-causing organisms.
(ii) Specimen F (soldier termite): speeds up decay by breaking down dead wood into humus, which increases soil fertility and improves soil drainage and aeration through its channels; it is a source of protein for poultry feed, and mud from the termitarium is used for building; however, it also destroys wood in roofs, houses, furniture, timber and crops.
(c)(i) Observable feature adapting each specimen against predation:
- Specimen E (cockroach): its dorso-ventrally flattened body lets it hide quickly in cracks and crevices, and its brown colour blends with the surroundings as camouflage; its wings also allow it to fly away from predators.
- Specimen F (soldier termite): its large, strong mandibles are used to bite in defence, and the snout-like projection of the head produces a poisonous defensive secretion for protection.
(c)(ii) Habitats: Specimen E (cockroach) lives in dark boxes, cupboards and cesspits; Specimen F (soldier termite) lives in the termitarium (termite mound/hill).
(d) Drawing of the dorsal view of Specimen E (cockroach) with all wings removed, 8-10 cm long, fully labelled:
Pregunta 3 Informe
(a) Study carefully specimens A, B, C, and D. copy and complete the table below
| Specimen | Part modified to form specimen | Mode of propagation | Stored material |
| A | |||
| B | |||
| C | |||
| D |
(b) In a tabular form state four observable differences between specimens A and C.
(c) Crush a small portion of specimen D and divide it into three equal parts. (i) Place a portion on a white tile and add two (2) drops of iodine solution.
(ii) Place another portion in a test tube and add one (1) ml of distilled water and shake. Add few drops of sodium hydroxide solution and shake again. Slowly add a few drop of 1% Copper (ii) sulphate solution. (iii) Smear the third part on a filter paper, leave for about five (5) minutes and observe carefully
The specimens are organs of vegetative propagation. A common WAEC set is: A, onion; B, ginger; C, Irish potato; D, cassava. The completed table follows that reading.
(a) Completed table
| Specimen | Part modified to form specimen | Mode of propagation | Stored material |
|---|---|---|---|
| A (Onion) | Modified leaves (fleshy leaf bases) forming a bulb | By bulb | Carbohydrate (sugar) / starch |
| B (Ginger) | Modified underground stem (rhizome) | By rhizome | Starch |
| C (Irish potato) | Modified underground stem (stem tuber) | By stem tuber | Starch |
| D (Cassava) | Modified root (root tuber) | By root tuber / stem cutting | Starch |
(b) Four observable differences between specimen A (onion bulb) and specimen C (potato stem tuber)
| Specimen A (onion) | Specimen C (Irish potato) |
|---|---|
| Formed from modified leaves | Formed from a modified stem |
| Made of concentric fleshy scale leaves | Is a single swollen solid structure |
| Has one main (terminal) bud | Has several buds (eyes) scattered over its surface |
| Food is stored in the fleshy leaf bases | Food is stored in the swollen stem tissue |
(c) Tests on the crushed specimen D (cassava)
| Test | Observation | Inference |
|---|---|---|
| (i) Portion + two drops of iodine solution | Turns blue-black | Starch is present |
| (ii) Portion + distilled water + sodium hydroxide + copper (II) sulphate | Remains blue (no purple colour) | Protein is absent (or present in only a trace) |
| (iii) Portion smeared on filter paper, left five minutes | No permanent translucent (grease) spot | Oil / lipid is absent |
Detalles de la respuesta
The specimens are organs of vegetative propagation. A common WAEC set is: A, onion; B, ginger; C, Irish potato; D, cassava. The completed table follows that reading.
(a) Completed table
| Specimen | Part modified to form specimen | Mode of propagation | Stored material |
|---|---|---|---|
| A (Onion) | Modified leaves (fleshy leaf bases) forming a bulb | By bulb | Carbohydrate (sugar) / starch |
| B (Ginger) | Modified underground stem (rhizome) | By rhizome | Starch |
| C (Irish potato) | Modified underground stem (stem tuber) | By stem tuber | Starch |
| D (Cassava) | Modified root (root tuber) | By root tuber / stem cutting | Starch |
(b) Four observable differences between specimen A (onion bulb) and specimen C (potato stem tuber)
| Specimen A (onion) | Specimen C (Irish potato) |
|---|---|
| Formed from modified leaves | Formed from a modified stem |
| Made of concentric fleshy scale leaves | Is a single swollen solid structure |
| Has one main (terminal) bud | Has several buds (eyes) scattered over its surface |
| Food is stored in the fleshy leaf bases | Food is stored in the swollen stem tissue |
(c) Tests on the crushed specimen D (cassava)
| Test | Observation | Inference |
|---|---|---|
| (i) Portion + two drops of iodine solution | Turns blue-black | Starch is present |
| (ii) Portion + distilled water + sodium hydroxide + copper (II) sulphate | Remains blue (no purple colour) | Protein is absent (or present in only a trace) |
| (iii) Portion smeared on filter paper, left five minutes | No permanent translucent (grease) spot | Oil / lipid is absent |
