Theory question 105
Ecosystem and Ecological FactorsSection B
(a) State five effects of high temperature on organisms in their habitats.
(b) Mention five effects of bush burning on the ecosystem.
(c) State four roles of the World Health Organization in the control of pandemic diseases.
(d)(i) Explain briefly countershading as an adaptive feature of Tilapia in freshwater habitats. (ii) Explain briefly seasonal migration in birds.
(e) Name: (i) five groups of microorganisms. (ii) two groups among the groups named in 5(e)(i) which have members that are pathogenic.
(f) A patient with blood group O requires blood transfusion. (i) Name two blood groups that the patient should not be transfused with. (ii) State two likely effects that the transfusion of any of the blood groups named in 5(f)(i) would have on the patient.
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(a) Any five: increased water loss and wilting/dehydration; denaturing of enzymes and death; faster metabolism and respiration; animals seek shade or burrow (behavioural changes); aestivation; reduced dissolved oxygen in water; heat stress/sunburn; affects germination and flowering.
(b) Any five: kills plants, animals and soil organisms; destroys habitats; removes vegetation cover, leading to erosion; destroys humus and soil structure; releases carbon (IV) oxide and smoke (air pollution, global warming); loss of nutrients by volatilisation; encourages fire-resistant grasses (succession changes).
(c) Any four: monitors and reports disease outbreaks worldwide; issues guidelines and alerts to countries; supports vaccine development and vaccination campaigns; supplies drugs, equipment and experts; trains health workers; coordinates research and public health education.
(d)(i) Tilapia is dark on its back and pale on its belly. Seen from above it blends with the dark water/bottom, and seen from below it blends with the bright surface, so predators find it hard to see.
(ii) Seasonal migration is the regular movement of birds from one region to another at certain seasons (e.g. to escape cold or dry seasons and find food or breeding places), and their return later, e.g. swallows, cattle egrets.
(e)(i) Bacteria; viruses; fungi; protozoa; algae (accept rickettsia).
(ii) Any two of: bacteria, viruses, fungi, protozoa.
(f)(i) Any two: A; B; AB.
(ii) Any two: agglutination (clumping) of the donor red cells; blocked blood vessels; haemolysis of red cells; fever, shock, kidney failure or death.
Group O has anti-A and anti-B antibodies in its plasma, so it can receive only group O blood.