Question 1
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 C, D and E carefully and answer questions 1 (a) to 1 (e).
- (i) Name the phylum to which specimens C and E belong. [1 mark]
(ii) State two reasons for the answer in 1 (a) (i). [2 marks] - State three observable structural differences between the following specimens;
((i) C and D [3 marks]
(ii) C and E [3 marks] - What is the relationship between specimens C and D? [1 mark]
- (i) Name the habitat of specimen D. [1 mark]
(ii) State two ways in which specimen D is adapted to its habitat. [4 marks] - Make a drawing, 8cm-10cm long of the dorsal view of specimen C and label fully. [10 marks]
Observation
Some candidates could not spell the term ‘Arthropoda’ correctly. Some candidates wrote only segmentation instead of metameric segmentation which made them lose marks. Some candidates were unable to distinguish specimens C, D and E, hence, their features were mixed up and the performance was poor. Some candidates could also not state the corresponding differences between specimens C, D and E. It was observed that just a few candidates performed well in questions 1. Some candidates were not able to state the features that adapt specimen D to its habitat. The drawing of the dorsal view of specimen C was also very poor.
The expected answers are:
(i) Phylum of Specimens C/Butterfly and E/Grasshopper
Arthropoda(ii) Reasons for the answer in 1 (a) (i)
- Metameric segmentation/segmented bodies;
- Jointed appendages;
- Presence of chitinous exoskeleton/exoskeleton made of chitin;
- Bilateral symmetry.
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Difference between
(i)
- Relationship between specimens C/Butterfly and D/Caterpillar
- C/Butterfly is the adult/imago of D/Caterpillar;
- D/Caterpillar is the larva/larval stage of C/Butterfly.
(i) Habitat of specimen D/Caterpillar
Garden/citrus leaves/vegetables/leaves/fruits(ii) Ways in which Specimen D/Caterpillar is adapted to its habitat
- Mandibles; for chewing;
- It has three pairs of true legs with claws; for locomotion;
- It has claspers; for attachment to vegetation/twig;
- Presence of four pairs of prolegs/false legs; for climbing;
- Its coloured pattern; enables it to blend with its environment/camouflage/escape predators;
- It has spiracles; for gaseous exchange;
- It has simple eyes; for vision;
- Has osmeterium; as defence mechanism/which emits foul smell to scare away predators.
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