Theory question 106
Behaviour(For candidates in Nigeria only)
(a) State five reasons why animals move from place to place.
(b) State one function each of the following structures found in plants: (i) epidermis; (ii) phloem; (iii) sclerenchyma.
(c) Give two examples each of the following types of organisms: (i) parasitic plants; (ii) saprophytes.
(d) State two adaptive features of plants which inhabit salt water swamp.
(e) State two factors each which result in: (i) increase; (ii) decrease, in population density.
(f) Mention four ways in which modern agricultural activities may threaten the survival of species.
(g) State three reasons why mitosis is important to living organisms.
(h) State three causes of food spoilage.
Show the model answer
(a) Any five: search for food; search for water; find mates; escape predators/danger; find shelter; avoid unfavourable conditions (heat, cold, drought); find breeding sites; avoid overcrowding/competition.
(b)(i) Epidermis: protects inner tissues / reduces water loss / gas exchange through stomata. (ii) Phloem: transports manufactured food (translocation). (iii) Sclerenchyma: gives mechanical support and strength.
(c)(i) Dodder (Cuscuta), mistletoe (Loranthus), Striga. (ii) Mushroom, Rhizopus/Mucor (bread mould), bacteria of decay.
(d) Any two: breathing roots (pneumatophores) for air; stilt/prop roots for support in soft mud; salt glands/succulent leaves to deal with salt; viviparous seeds (germinate on the parent); thick cuticle.
(e)(i) Increase: high birth rate (natality); immigration; abundant food; absence of predators/disease. (ii) Decrease: high death rate; emigration; food shortage; predation; disease; natural disasters.
(f) Any four: clearing forests (habitat destruction); use of pesticides and herbicides that kill non-target species; bush burning; monoculture reducing variety; fertiliser run-off polluting water; draining of wetlands; overgrazing.
(g) Any three: growth of the organism; repair and replacement of worn-out or damaged cells; asexual reproduction; keeps the chromosome number constant in body cells (identical daughter cells).
(h) Any three: microorganisms (bacteria, fungi); enzymes within the food; insects and rodents; moisture; warm temperature; exposure to air (oxidation).
Many short parts: give exactly the number of points asked for each.