Question 1
(a) (i) What is metamorphosis in insects? [2 marks]
(ii) Complete the table below
Two types of metamorphosis |
Three examples each of insects that undergo the type of metamorphosis |
I |
(i) |
II |
(i) |
[8 marks]
(iii) Explain briefly each of the types of metamorphosis named in 1(a)(ii).
I
II
[6 marks]
(b) Name one insect each that is associated with the following stages of development.
(i) maggot;
(ii) chrysalis;
(iii) caterpillar
(iv) nymph.
Observation
Many candidates attempted this question and the performance was average because many candidates missed the spellings of complete and incomplete. Some also wrongly put the insects in under the types of metamorphosis.
Some candidates even wrote toad as insect. Where they got the answers right, they missed the spelling of the names of insects. Some candidates were not able to name insects that were associated with chrysalis but could name the one associated with maggot.
The expected answers are:
- (a) (i) Metamorphosis
Is a series of gradual changes; that occurs during the development of an insect; from fertilised egg/immature stage to adult/mature stage.
(ii)Table
Types of metamorphosis |
Examples of insects that undergo the types of metamorphosis |
Complete |
Mosquito; ant; housefly; butterfly; Tsetse fly; bee; moth; beetle; weevil; flea; wasp. |
Incomplete |
Termite; aphid; grasshopper; cockroach; locust; cricket; bedbug; cicadas; louse; praying mantis/mantids; damsel fly. |
Note: spelling of examples of insect should be correct to score.
(iii) Explanation of types of metamorphosis
Complete metamorphosis
- Is a type of life cycle; which involves complete change of form at each stage;
- involves four stages/egg, larva, pupa and imago/adult;
- Larva is the most active feeding stage;
- Pupa is the dormant/inactive/resting stage;
- Adult stage is sexually mature.
Incomplete metamorphosis
- It is a type of life cycle; which involves a gradual change of form at each stage;
- It involves three stages/egg, nymph and imago/adult;
- The nymph stage closely resembles the adult; nymph stage is more often wingless;
- The nymph stage is sexually immature.
(b) Insect associated with the following stages of development
- maggot
housefly; cheese fly; blowfly
- chrysalis
butterfly; moth
- caterpillar
butterfly; aphid; moth
- Nymph
cockroach; grasshopper; termite; aphid; dragonfly; praying mantis/mantids; cricket; bed bud; louse.