Theory question 103
Feeding Relationships and Energy Flow(a) Complete the table below by placing each of the following organisms under the appropriate heading:
Algae, Bacteria, Dog, Water lettuce, Tadpole, Cat, Lemna, Waterleaf, Mucor, Mushroom
Headings: Decomposer | Producer | Consumer
(b)(i) Name four products of decomposition. (ii) Mention three roles of decomposers on a refuse dump.
(c) List three materials found in a refuse dump which would not be affected by the action of decomposers.
Show the model answer
(a) Decomposer: bacteria, Mucor, mushroom. Producer: algae, water lettuce, Lemna, waterleaf. Consumer: dog, tadpole, cat.
(b)(i) Any four: carbon dioxide; water; ammonia/ammonium compounds; mineral salts (nitrates, phosphates); humus; heat; methane.
(ii) Any three: break down dead organic matter and waste; reduce the volume of refuse; recycle nutrients back to the soil; remove bad smell and clean the environment; form manure/compost.
(c) Any three: plastics/polythene; glass; metals (cans, iron); rubber; ceramics; stones.
Non-biodegradable materials stay in the dump because decomposers cannot digest them.