(a)(i) Identify organisms A and B. [2 marks] (ii) Name the parts labeled I to X. [5 marks] (b) State one function each of the parts labeled VI, VIII, IX and...

This question tests your ability to observe two insect specimens, name their external parts, and compare their structures. Organism A is a butterfly and organism B is a housefly. Both belong to the class Insecta, so the reasoning throughout is a comparison of two insects that share a common body plan (head, thorax, abdomen; three pairs of legs; one pair of antennae) but show different adaptations.

(a)(i) Identity of the organisms

• A: Butterfly
• B: Housefly

(a)(ii) Names of the parts labelled I to X

(b) One function each of the parts labelled VI, VIII, IX and X

• VI (antenna): a sense organ that detects smell and touch, helping the insect locate food and sense its surroundings.
• VIII (thorax): bears the wings and legs and encloses the flight muscles, so it is the region responsible for locomotion.
• IX (wing): used for flight, enabling the insect to move from place to place.
• X (leg): used for walking, standing and gripping surfaces (in the housefly it also carries taste receptors).

(c) Specific habitats

• Organism A (butterfly): gardens, farmland and bushes where flowering plants grow, because it feeds on nectar.
• Organism B (housefly): refuse dumps, decaying organic matter and human dwellings, where it feeds and breeds.

(d) Three structural adaptations of organism A (butterfly) to its mode of life

1. A long, coiled, tube-like proboscis that uncoils to suck nectar from deep inside flowers.
2. Two pairs of large, broad wings covered with scales that provide a wide surface for flight from flower to flower.
3. Clubbed antennae and large compound eyes that detect the scent and colour of flowers.

(e)(i) Three structural similarities between organisms A and B

1. The body of each is divided into head, thorax and abdomen.
2. Each has three pairs of jointed legs attached to the thorax.
3. Each bears a pair of antennae and a pair of compound eyes on the head.

(e)(ii) Three structural differences between organisms A and B

(f)(i) Class of organisms A and B

Both organisms belong to the class Insecta.

(f)(ii) Three reasons for the answer in (f)(i)

1. The body of each is clearly divided into three parts: head, thorax and abdomen.
2. Each has three pairs of jointed legs (six legs in all).
3. Each possesses one pair of antennae, with wings borne on the thorax.

(g) One biological importance of organism A (butterfly)

As it moves from flower to flower feeding on nectar, the butterfly carries pollen on its body and brings about pollination, which helps flowering plants to reproduce.

Examination tip: when a specimen question asks you to identify parts, follow each leader line to the exact structure it touches and give the precise term (for example "compound eye" rather than just "eye", or "forewing" and "hindwing" rather than just "wing") - the specific term is what earns the mark.