Question 4
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 specimen R carefully and answer questions 4(a) to 4(c).
- (i) Name the phylum of specimen R. [1 mark]
(ii) State two reasons for the answer in 4 (a)(i). [2 marks]
(iii) State the habitat of specimen R. [1 mark] - (i) State two structural features that adapt specimen R to its habitat. [4 marks]
(ii) State three ways in which specimen R is of economic importance. [3 marks] - Make a drawing, 8cm-10cm long of the dorsal view of specimen R and label fully. [10 marks] Study specimens S and T carefully and answer questions 4(d) to 4(e).
- What type of fruits are specimens S and T? [2 marks]
- (i) State four observable differences between specimens S and T. [4 marks]
(ii) State four observable similarities between specimens S and T. [4 marks]
Observation
Most candidates could not state the observable features of Specimen R, although, they could state the economic importance of Specimen R. The structural features that adapt specimen R to its habitat were badly attempted. Most candidates could identify the type of fruit and give differences and similarities between specimens S and T.
The expected answers are:
- (i) Phylum of Specimen R/Earthworm
Annelida.(ii) Reasons for the classification of Specimen R/Earthworm
- Presence of metameric segmentation/segments are separated from each other (by septa);
- They are bilaterally symmetrical;
- Segments are separated from each other;
- Presence of chaetae;
- Body is covered by thin collagen cuticle;
- Body is long and cylindrical.
(iii) Habitat of Specimen R/Earthworm
- Under decaying leaves;
- Wet/moist soil;
- In open savanna/savannah beneath the tall grasses;
- In the forests in decaying tree-stumps.
(i) Features of adaptation of Specimen R/Earthworm
- Bristle-like chaetae/seatae; for locomotion;
- Moist skin; for gaseous exchange;
- Pointed anterior; for burrowing into the soil;
- Slimy body; reduces friction during movement;
- Clitellum; for attachment during exchange of sperms/reproduction/secretes cocoon (in which its eggs are deposited).
Note: Structure and function must correspond to score
(ii) Economic importance of Specimen R/Earthworm
- It aerates the soil;
- It enriches/improves soil fertility;
- Its secretions neutralize the acid soil;
- Used as bait for fishing;
- As food for some birds.
- Diagram/Drawing of the dorsal view of Specimen R/Earthworm
- Type of fruit
Specimen S/unripe mango fruit – Drupe
Specimen T/tomato fruit - Berry - (i) Observable differences between specimens S and T
(ii) Similarities between specimens S and T
- Both have seeds;
- Both are fruits;
- Both have three layers/epicarp/mesocarp/endocarp/pericarp/fruit wall;
- Coloured epicarp/pericarp;
- Both have placenta;
- Both have fleshy mesocarp.