WAEC SSCE - Biology - 2012 (Practical)
Ajụjụ 1 Ripọtì
(a) Study carefully specimens A and B and use them to answer questions 1(a) to 1(c).
(a)(i) Name the types of fruit in specimens A and B with reasons.
(ii) Make a drawing, 8-10cm long of the lateral view of specimen B and label fully.
(b) Describe the modes of dispersal of specimens A and B.
(c) In a tabular form, state five differences between specimens A and B.
(a)(i) Types of fruit in specimens A and B, with reasons
Specimen A (garden egg): a berry. Reason: it has a fleshy pericarp with many seeds embedded in it.
Specimen B (Tridax fruit): a cypsela. Reason: it is a dry, single-seeded fruit that develops from an inferior ovary and bears a hairy pappus (parachute) formed from the modified calyx.
(a)(ii) Labelled drawing of the lateral (side) view of specimen B (Tridax fruit)
The drawing below shows the lateral view of the Tridax cypsela, made 8-10 cm long and fully labelled.
(b) Modes of dispersal of specimens A and B
Specimen A (garden egg): dispersed by animals. The fleshy, edible fruit is eaten by animals; the seeds pass through the gut unharmed and are voided in the droppings some distance away.
Specimen B (Tridax fruit): dispersed by wind. The light, dry fruit bears a crown of feathery pappus hairs (a parachute) that increases its surface area, so it is easily carried away by air currents.
(c) Five differences between specimens A and B
| Specimen A (Garden egg) | Specimen B (Tridax fruit) |
|---|---|
| Fleshy pericarp | Dry pericarp |
| Smooth epicarp (fruit wall) | Hairy epicarp (fruit wall) |
| Pappus absent; calyx present beneath the fruit | Pappus present (calyx modified into a pappus) on top of the fruit |
| Large and heavy fruit | Small and light fruit |
| Green, white or yellow in colour | Brown in colour |
Akọwa Nkọwa
(a)(i) Types of fruit in specimens A and B, with reasons
Specimen A (garden egg): a berry. Reason: it has a fleshy pericarp with many seeds embedded in it.
Specimen B (Tridax fruit): a cypsela. Reason: it is a dry, single-seeded fruit that develops from an inferior ovary and bears a hairy pappus (parachute) formed from the modified calyx.
(a)(ii) Labelled drawing of the lateral (side) view of specimen B (Tridax fruit)
The drawing below shows the lateral view of the Tridax cypsela, made 8-10 cm long and fully labelled.
(b) Modes of dispersal of specimens A and B
Specimen A (garden egg): dispersed by animals. The fleshy, edible fruit is eaten by animals; the seeds pass through the gut unharmed and are voided in the droppings some distance away.
Specimen B (Tridax fruit): dispersed by wind. The light, dry fruit bears a crown of feathery pappus hairs (a parachute) that increases its surface area, so it is easily carried away by air currents.
(c) Five differences between specimens A and B
| Specimen A (Garden egg) | Specimen B (Tridax fruit) |
|---|---|
| Fleshy pericarp | Dry pericarp |
| Smooth epicarp (fruit wall) | Hairy epicarp (fruit wall) |
| Pappus absent; calyx present beneath the fruit | Pappus present (calyx modified into a pappus) on top of the fruit |
| Large and heavy fruit | Small and light fruit |
| Green, white or yellow in colour | Brown in colour |
Ajụjụ 2 Ripọtì
Study carefully specimens C, D and E and use them to answer questions 2(a) to 2(c).
(a) (i) State the mode of nutrition of specimen D.
(ii) State one way by which each of specimens C, D and E is of economic importance.
(b)(i) Classify specimens C, D and E into their phyla and classes.
(ii) List three observable characteristic features of each of the classes to which specimens C, D and E belong.
(iii) In a tabular form, state two observable differences between C and D.
(C) List four observable features of specimen E that are sensory in nature.
(a)(i) Mode of nutrition of specimen D (tick): parasitic (it sucks blood from its host).
(a)(ii) One way each is of economic importance
- C (grain weevil): it destroys stored grains and lowers their quality, reducing the farmer's income.
- D (tick): it infests cattle and dogs, sucking blood and making them anaemic, and it transmits diseases.
- E (rat): it destroys and contaminates stored food and spreads diseases.
(b)(i) Classification into phyla and classes
| Specimen | Phylum | Class |
|---|---|---|
| C (grain weevil) | Arthropoda | Insecta |
| D (tick) | Arthropoda | Arachnida |
| E (rat) | Chordata | Mammalia |
(b)(ii) Three observable characteristic features of each class
- Insecta (C): body in three divisions (head, thorax, abdomen); three pairs of jointed walking legs; a pair of antennae; compound eyes (and usually wings).
- Arachnida (D): body in two divisions (cephalothorax and abdomen); four pairs of legs; no antennae; simple eyes; feeding appendages (pedipalps and chelicerae).
- Mammalia (E): body covered with hair/fur; external ears (pinnae); mammary glands; four limbs; heterodont dentition.
(b)(iii) Two observable differences between C and D
| Specimen C (grain weevil) | Specimen D (tick) |
|---|---|
| Body in three divisions with a distinct thorax | Body in two divisions; thorax fused with head (cephalothorax) |
| Three pairs of legs; antennae present; wings present | Four pairs of legs; antennae absent; wings absent |
(c) Four observable sensory features of specimen E (rat): the eyes (sight), the external ears/pinnae (hearing), the nostrils (smell) and the whiskers (touch).
Akọwa Nkọwa
(a)(i) Mode of nutrition of specimen D (tick): parasitic (it sucks blood from its host).
(a)(ii) One way each is of economic importance
- C (grain weevil): it destroys stored grains and lowers their quality, reducing the farmer's income.
- D (tick): it infests cattle and dogs, sucking blood and making them anaemic, and it transmits diseases.
- E (rat): it destroys and contaminates stored food and spreads diseases.
(b)(i) Classification into phyla and classes
| Specimen | Phylum | Class |
|---|---|---|
| C (grain weevil) | Arthropoda | Insecta |
| D (tick) | Arthropoda | Arachnida |
| E (rat) | Chordata | Mammalia |
(b)(ii) Three observable characteristic features of each class
- Insecta (C): body in three divisions (head, thorax, abdomen); three pairs of jointed walking legs; a pair of antennae; compound eyes (and usually wings).
- Arachnida (D): body in two divisions (cephalothorax and abdomen); four pairs of legs; no antennae; simple eyes; feeding appendages (pedipalps and chelicerae).
- Mammalia (E): body covered with hair/fur; external ears (pinnae); mammary glands; four limbs; heterodont dentition.
(b)(iii) Two observable differences between C and D
| Specimen C (grain weevil) | Specimen D (tick) |
|---|---|
| Body in three divisions with a distinct thorax | Body in two divisions; thorax fused with head (cephalothorax) |
| Three pairs of legs; antennae present; wings present | Four pairs of legs; antennae absent; wings absent |
(c) Four observable sensory features of specimen E (rat): the eyes (sight), the external ears/pinnae (hearing), the nostrils (smell) and the whiskers (touch).
Ajụjụ 3 Ripọtì
Study carefully specimens J, K and L and use them to answer questions 4(a) to 4(d).
(a)(i) State the class of each of specimens J, K and L
(ii) State three reasons each for placing each of specimens J, K and L in their classes.
(b) State two structural adaptations possessed by each of specimens K and L for escaping predators.
(c) Make a drawing, 8 - 10cm long of the lateral view of specimen J.
(d) State: (i) two similarities; (ii) two observable differences between specimens J and L.
(a)(i) Class of each specimen
- Specimen J (tilapia): Class Osteichthyes (bony fishes).
- Specimen K (toad): Class Amphibia.
- Specimen L (lizard): Class Reptilia.
(a)(ii) Three reasons for placing each specimen in its class
Specimen J (Osteichthyes):
- The body is covered with thin, overlapping bony scales.
- It possesses paired fins (pectoral and pelvic fins).
- A lateral line runs along each side of the body.
- The gills are covered by a bony operculum (gill cover).
Specimen K (Amphibia):
- The skin is moist and warty (glandular), without scales.
- The hind limbs bear webbed digits.
- It has large, bulging eyes.
- A visible ear drum (tympanum) lies behind each eye.
Specimen L (Reptilia):
- The skin is dry and covered with horny scales.
- It has two pairs of limbs bearing clawed digits.
- The teeth are all alike (homodont dentition).
- It possesses a well-developed, retractable tongue.
(b) Two structural adaptations for escaping predators
Specimen K (toad):
- Poison (parotoid) glands in the skin secrete an irritant substance that repels predators.
- Long, muscular hind limbs enable it to leap swiftly away from danger, while counter-shading of the dorsal and ventral surfaces camouflages it.
Specimen L (lizard):
- The tail is detachable (autotomy); it can be shed to distract a predator while the lizard escapes.
- The skin colouration blends with the surroundings (camouflage), concealing it from predators.
(c) Drawing, 8 - 10 cm long, of the lateral view of specimen J (tilapia)
The lateral (side) view of the tilapia is shown below, drawn 8 - 10 cm long with the parts clearly labelled.
(d)(i) Two similarities between specimens J and L
- Both possess eyes and a pair of nostrils on the head.
- Both have a body covered with scales and bear a tail.
(d)(ii) Two observable differences between J and L
| Specimen J (tilapia) | Specimen L (lizard) |
|---|---|
| Possesses fins for movement | Possesses limbs for movement |
| Lateral line and operculum (gill cover) present | Lateral line and operculum absent |
Akọwa Nkọwa
(a)(i) Class of each specimen
- Specimen J (tilapia): Class Osteichthyes (bony fishes).
- Specimen K (toad): Class Amphibia.
- Specimen L (lizard): Class Reptilia.
(a)(ii) Three reasons for placing each specimen in its class
Specimen J (Osteichthyes):
- The body is covered with thin, overlapping bony scales.
- It possesses paired fins (pectoral and pelvic fins).
- A lateral line runs along each side of the body.
- The gills are covered by a bony operculum (gill cover).
Specimen K (Amphibia):
- The skin is moist and warty (glandular), without scales.
- The hind limbs bear webbed digits.
- It has large, bulging eyes.
- A visible ear drum (tympanum) lies behind each eye.
Specimen L (Reptilia):
- The skin is dry and covered with horny scales.
- It has two pairs of limbs bearing clawed digits.
- The teeth are all alike (homodont dentition).
- It possesses a well-developed, retractable tongue.
(b) Two structural adaptations for escaping predators
Specimen K (toad):
- Poison (parotoid) glands in the skin secrete an irritant substance that repels predators.
- Long, muscular hind limbs enable it to leap swiftly away from danger, while counter-shading of the dorsal and ventral surfaces camouflages it.
Specimen L (lizard):
- The tail is detachable (autotomy); it can be shed to distract a predator while the lizard escapes.
- The skin colouration blends with the surroundings (camouflage), concealing it from predators.
(c) Drawing, 8 - 10 cm long, of the lateral view of specimen J (tilapia)
The lateral (side) view of the tilapia is shown below, drawn 8 - 10 cm long with the parts clearly labelled.
(d)(i) Two similarities between specimens J and L
- Both possess eyes and a pair of nostrils on the head.
- Both have a body covered with scales and bear a tail.
(d)(ii) Two observable differences between J and L
| Specimen J (tilapia) | Specimen L (lizard) |
|---|---|
| Possesses fins for movement | Possesses limbs for movement |
| Lateral line and operculum (gill cover) present | Lateral line and operculum absent |
