Biology Paper 3 (Practical), WASSCE (SC), 2017

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).
  1. (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]
  2. (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]
  3. Make a drawing, 8cm-10cm long of the dorsal view of specimen R and label fully. [10 marks]
  4. Study specimens S and T carefully and answer questions 4(d) to 4(e).
  5. What type of fruits are specimens S and T? [2 marks]
  6. (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:

 

  1. (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.

  2. (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.

  3.  

  4. Diagram/Drawing of the dorsal view of Specimen R/Earthworm
  5.  

  6. Type of fruit

    Specimen S/unripe mango fruit – Drupe
    Specimen T/tomato fruit - Berry

     

  7. (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.