Theory question 103
Soil(a) Name one instrument used for collecting: (i) soil organisms from a soil sample; (ii) tiny insects from a leaf or a stem. (b) Make a diagram 6cm — 8cm long of the instrument named in 3(a)(ii) and label fully. (c) Explain briefly the relationship between three examples of symbiotic organisms.
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(a)(i) Tullgren funnel (or Baermann funnel for soil nematodes).
(ii) Pooter (aspirator).
(b) Diagram of a pooter, 6–8 cm long, with title and labels: specimen tube/bottle, rubber bung (cork), inlet tube (short tube put near the insect), mouthpiece tube (sucking tube), gauze/muslin covering the inner end of the mouthpiece tube.
(c) Any three pairs, each with how both benefit: Rhizobium bacteria and legumes – bacteria fix nitrogen for the plant, plant gives food and shelter in root nodules; lichen (alga and fungus) – alga makes food, fungus holds water and gives shelter; hermit crab and sea anemone – anemone protects the crab, crab carries the anemone to food; termites and cellulose-digesting protozoa in their gut – protozoa digest wood for the termite and get food and shelter; cattle and rumen bacteria – bacteria digest cellulose, get food and a warm home.
For symbiosis, say what each partner gains in every example.