a. Complete the table below. Organism Mode of feeding Feature of mouthpart that adapts organism to mode of feeding [6 marks] b. List five parts of the alime...

Answer Details

(a) Completed table of organisms, mode of feeding and the adapting mouthpart feature:

(Butterfly, with a long coiled proboscis for sucking nectar, and honeybee, with mandibles plus a long tongue for chewing and lapping, are also acceptable entries.)

(b) Five parts of the alimentary canal of an earthworm: pharynx, oesophagus, crop, gizzard, intestine (the full canal runs mouth, buccal cavity, pharynx, oesophagus, crop, gizzard, intestine, anus).

(c) Six ways water can be polluted by agricultural practices:

• Chemical fertilizers washed (leached) into rivers and lakes, causing eutrophication.
• Insecticides and pesticides running off farmland into water bodies.
• Herbicides washed from sprayed crops into streams.
• Animal droppings and livestock waste washed into water.
• Soil erosion from cultivated land silting up water bodies.
• Improper disposal of decaying farm and organic waste into water.

(d) Life cycle of a housefly (complete metamorphosis): The adult female lays batches of eggs on decaying organic matter such as refuse or faeces. Each egg hatches into a larva (maggot) that feeds actively, grows and moults. The larva then changes into an inactive pupa enclosed in a puparium, within which the body is reorganised. Finally an adult fly (imago) emerges, matures and mates, and the cycle repeats: egg to larva to pupa to adult.

(e) Hypogeal germination in maize: the diagram should show the grain remaining below the soil (the cotyledon and food-storing endosperm stay underground), the coleoptile pushing vertically up through the soil, the first foliage leaf emerging from the tip of the coleoptile above ground, the primary (radicle) root growing downward, and the fibrous seminal/adventitious roots. The soil line should be marked, with the grain and roots below it and the shoot above it.