Question 3
4. Study specimens P and Q and answer questions 4(a) to 4(e).
(a) (i) State the sex of specimen P. [1 mark]
(ii) Give one reason for the answer in 4(a)(i). [1 mark]
(b)(i) Name the habitats of each of specimens P and Q. [2 marks]
(ii) State three adaptations each of specimens P and Q to their habitats. [12 marks]
(c) (i) State one observable structural difference between specimens P and Q.[1 mark]
(ii) State three observable structural similarities between specimens P and Q. [3 marks]
(d) (i) Observe the mouthpart of specimen Q and state its feeding mechanism. [1 mark]
(ii) List one food item which specimen Q feeds on. [1 mark]
(e) Remove carefully one of the legs on the right side of the metathorax of specimen P. Make a drawing, 6 cm to 8 cm long of the removed leg and label fully. [8 marks]
Observation
Most candidates were able to state the correct sex of specimen P ( cockroach) but they were unable to state the reason for the answer. Some even wrote presence of testes, size of the specimen, presence of cerci, size of wings, size of jointed legs/appendages e.t.c.
Many candidates could name the habitat of the specimens although some candidates generalized the answer by writing terrestrial habitat.
Many candidates were able to give correct adaptations of the specimens to their habitats while some only gave the feature without stating the function.
Some candidates also lost some marks because they did not qualify the features e.g. eye instead of compound eye, hind legs instead of long/muscular hind leg for hopping.
`Many candidates lost marks for not giving the correct colour of the specimens.
Some candidates were unable to give the correct feeding mechanism of specimen Q (grasshopper). A few gave mandible or maxilla.
Many candidates correctly gave the food item specimen Q (grasshopper) feeds on.
Most candidates do not really know what is required of them in terms of quality of diagrams such as pencil line quality, drawing of guidelines with ruler to touch the label, non-use of arrow heads in guidelines, non-shading of diagrams and drawing to the specified size, hence, they lost marks.
The expected answers are:
4. (a) (i) Sex of Specimen P/Cockroach Male
(ii) Reason
Presence of anal style(s)
(b) (i) Habitat of Specimens P/Cockroach and Q/Grasshopper
Specimen P/Cockroach
pit toilet/dark boxes/soak away/ wardrobe/kitchen/dark cupboard/book shelves/crevices/cracks any other correctly named habitat.
Specimens Q/Grasshopper
Garden/farmland/vegetation/grassland.
(ii) Adaptations of Specimens P/Cockroach and Q/Grasshopper to their habitat
Specimen P/Cockroach
- Flat/dorsoventrally flattened body; to move between small cracks/crevices/spaces;
- Jointed legs; for fast movement (to escape from predators);
- (Membraneous) wings; for flight (in an emergency case to escape from predators);
- Dark brown colour of body; serves as camouflage (from predators);
- Well developed mandibles/mouthparts; for feeding;
- Long antennae; for sensitivity;
- Compound eyes; for vision;
- Hardened forewings/chitinous exoskeleton; for protection;
- Spiracles; for gaseous exchange.
Specimen Q/Grasshopper
- (Green) colour of body; for camouflage (from predators);
- (A pair of)antennae; to detect vibrations and smell/sensitivity;
- (Numerous abdominal) spiracles; for gaseous exchange;
- (Presence of) well developed/powerful mandibles/mouthparts/chewing/feeding; for tearing;
- Jointed legs; for fast movement (to escape from predators);
- (Membraneous) wings; for flight (from predators);
- (A pair of) compound eyes; for vision.
Note: structure and function must correspond to score.
(c) (i) Differences between specimens P and Q
Specimen P/Cockroach |
Specimen Q/Grasshopper |
|
green coloured body; |
|
cylindrical body; |
|
elongated hind leg/limb; |
|
one pair of wings; |
|
large/muscular/stout hind leg(s); |
|
short antennae; |
|
Row on spines on the inner side of the hind leg. |
Note: Points must correspond to score.
(ii) Similarities between specimens P and Q
Both have
- Membraneous wings;
- Segmented body;
- Three body divisions/head, thorax and abdomen;
- Three pairs of walking legs;
- Have jointed appendages;
- Presence of antennae;
- Biting chewing mouthparts;
- Exoskeleton of chitin;
- Compound eyes.
(d) (i) Feeding mechanism of specimen Q/Grasshopper
Biting and chewing (mouthparts).
(ii) Food item specimen Q/Grasshopper feeds on
Foliage leaves; young/tender stem/green stem/grass.
(e) Diagram of leg of specimen P/Cockroach
Title (TL)
Quality (Q)
Clarity of lines (CL)
Size (SZ) (6cm to 8 cm)
Neatness of labels (NL)
Magnification (MG) (x4 to x5)
Details (D)
Long tibia (LT)
Spines shown on tibia, femur and tarsus (SS)
Labels (L)
Coxa, trochanter, femur, tibia, tarsus, claw, spine