Biology Paper 2, WASSCE (SC), 2023

QUESTION 3
           
Relationships I, II, III, IV and V exist among some organisms in an ecosystem. Use them to answer questions 3(a) to 3(e).

I:    Organism A grows on dead organism B.
II:   Organism C feeds on the remnants of food left by organism D without affecting organism   D negatively or positively.
III: Organism E provides shelter for organism F while organism F transports organism E towards food.
IV: Organism G kills organism B for food.
 V:  Organism H feeds on organism J, causing J a disease.

a. Name the type of relationship in I, II, III, IV and V                                       [5 marks]

 

b. In relationship IV, what is the biological term for each of organisms B and G?

  • B;
  • G:                                                                                                        [2 marks]

c. Name one example each of organisms B to J.                                               [8 marks]

d .(i)  Name the relationship that is most beneficial to the ecosystem.              [1 mark]

(ii) Give one reason for the answer in 3(d)(i).                                                [1 mark]

e. (i) Give two examples of organism A.                                                           [2 marks]

(ii) Name the group to which organism A belongs.                                       [1 mark]

This question was popular among candidates and many did well in it. Some candidates however gave wrong responses to the feeding relationship I and V in question 3(a) by writing Saprophytic, Parasitic etc. instead of Saprophytism and Parasitism respectively.

The biological term for organisms B and G as well as their examples as required in questions 3(b)(i) and (ii) was correctly given by most candidates.

Many candidates could not give the correct name for organisms C, D, E and F in question 3(c).

Spelling mistakes made some candidates perform poorly in this question.

The expected answers are as follows: 
(a) Types of relationship
I:    Saprophytism
II:  Commensalism
III: Mutualism
IV: Predation
V:  Parasitism                                                                                                        

          (b)  Biological term for organisms B and G
 B - prey
G - predator                                                                                                                                                                                                                                  
(c)  Example of organisms B to J
B: Antelope/goat/sheep/cow/rabbit/guinea pig/rat/any other correctly named prey.
C: Remora fish
D: Shark     
E: Hermit crab
F: Sea anemone
G: Lion/tiger/leopard/cat/dog/snake /hawk/eagle/any other correctly named predator.
H: Tapeworm/tick/louse/Plasmodium/Ascaris
J: Human/pig/cattle/cow/sheep/dog/cat                                                              
                  
(d)     (i) Most beneficial relationship to the ecosystem
Saprophytism                                                                                                           

          (ii) Reason for answer
It is involved in nutrient recycling/replenishment of nutrients in the ecosystem.  

(e)     (i) Examples of organism A

  • Mushroom/Mucor/Rhizopus/Yeast;
  • Pseudomonas/Bacillus/Clostridium/Enterobacter/Escherichia spp./E. coli/Salmonella spp.                                                                                                                     

          (ii) Group to which organism A belongs
Fungi/Bacteria/mold/mould