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. III: Organism E provides shelter for organism F while organism F transports organism E towards food. IV: Organism H feeds on organism J, causing organism J a disease.
(a) Name the type of relationship in: I; II; III; IV; V.
(b) In relationship IV, what is the biological term for each of organization B and G? (i) B; (ii) G.
(c) Name one example each of organisms B to J.
(d)(i) Name the relationship that is most beneficial to the ecosystem. (ii) Give one reason for the answer 3(d)(i).
(e)(i) Give two examples of organism A. (ii) Name the group to which organism A belongs.

Accepted Answer

(a) Types of relationship: I: Saprophytism; II: Commensalism; III: Mutualism; IV: Predation. (Relationship V was not described in the excerpt provided.)
(b) Biological term for organisms B and G: B — prey; G — predator.
(c) Examples of organisms B to J: B: Antelope/goat/sheep/cow/rabbit/guinea pig/rat. C: Remora fish. D: Shark. E: Hermit crab. F: Sea anemone. G: Lion/tiger/leopard/cat/dog/snake/hawk/eagle. H: Tapeworm/tick/louse/Plasmodium/Ascaris. J: Human/pig/cattle/cow/sheep/dog/cat.
(d)(i) The most beneficial relationship to the ecosystem is Saprophytism. (ii) Reason: 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: Fungi/Bacteria/mold/mould.

WAEC Biology 2023 Theory — Question 5

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