(a) (i) Define the term metamorphosis. (ii) Name the two types of metamorphosis that organisms undergo and mention two organisms that undergo each type. (b)...

(a)(i) Metamorphosis

Metamorphosis is the series of changes in body form and structure that an animal undergoes from the egg (or young stage) to the adult stage.

(a)(ii) Two types of metamorphosis with organisms

• Complete metamorphosis (egg → larva → pupa → adult): butterfly and housefly (also mosquito, beetle, moth).
• Incomplete (partial) metamorphosis (egg → nymph → adult): cockroach and grasshopper (also termite, locust, dragonfly).

(b)(i) Four economic importances of insects (with examples)

• Pollination of flowers: honey bee – helps in fertilisation and fruit/seed formation.
• Production of useful products: honey bee – produces honey and wax; silkworm (moth larva) – produces silk.
• Serve as food: termites and locusts – eaten by humans and animals (source of protein).
• Destruction of crops (pests): grasshopper/locust – destroys farm crops, causing loss.
• Transmission of diseases (vectors): mosquito – transmits malaria; housefly – transmits typhoid and cholera; tsetse fly – transmits sleeping sickness.
• Decomposition: some beetles help to break down dung and dead matter.

(Any four, each with an example.)

(b)(ii) Four peculiar features of social insects

• They live together in large numbers in a colony (community).
• There is division of labour, with different castes performing different duties.
• They show polymorphism, that is, different body forms for different castes (queen, workers, soldiers, drones).
• They cooperate and communicate to build and defend the nest and to care for the young.
• Only certain members (the queen/king) are fertile and carry out reproduction.