WAEC Biology 2017 Theory Past Questions

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Classification of living things refers to the grouping of living things according to their similar characteristics.

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The binomial system of naming was discovered by a scientist known as Carolus Linnaeus.

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Reasons for classification: (i) Identification purpose (ii) Research purpose (iii) Reference purpose.

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In order of hierarchy: Kingdom, Phylum, Class, Order, Family, Genus, Species.

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(i) Features in common with living things: Possession of DNA; Possession of protoplasm. (ii) Features in common with non-living things: It has a crystalline structure; It becomes totally non-living if it is taken out of the living system (host cell).

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(i) Plant viral diseases: Groundnut rosette disease; Tobacco mosaic disease. (ii) Human viral diseases: Measles; Mumps; Influenza; AIDS (any two).

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Characteristics of enzymes: They are specific in their actions; They are proteinous in nature; They are sensitive to pH; They are destroyed when the temperature is too high.

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The enzymes released into the duodenum include lipase, amylase and trypsin. Lipase acts on fats and oils; Amylase acts on starch; Trypsin acts on protein (peptone).

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Lipase converts fats and oils to fatty acid and glycerol; Amylase converts starch to maltose; Trypsin converts peptone to polypeptide.

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Chlorophyll is required by plants for photosynthesis.

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The elements needed for chlorophyll formation are iron, nitrogen and magnesium. Magnesium deficiency leads to poor growth and chlorosis. Iron deficiency causes chlorosis and stunted growth. Nitrogen deficiency causes chlorosis and poor flower development (any two elements with their deficiency symptoms).

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How to test for starch in a leaf: Heat the leaf in boiling water; Heat it in boiling ethanol; Wash the leaf with water and then spread it on a white tile; Add iodine solution and allow it to stand for a few minutes. NB: If starch is present, the leaf turns blue-black.

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We use a Tullgren funnel for collecting soil organisms. We use a pooter (potter) for collecting tiny insects from a leaf or stem.

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A labelled diagram of a pooter (potter), showing: the open end for insect passage, the longer delivery tube leading to the vessel/container (specimen tube), the gauze/netting/cotton wool (to prevent insects being inhaled), the shorter delivery/suction tube, the stopper/bung/cork, and the open end to mouth for sucking.

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(i) Nitrogen fixing bacteria and leguminous plants: The nitrogen fixing bacteria (e.g. Rhizobium) helps the leguminous plant in nitrogen fixation. In return, the plants provide food and shelter for the bacteria. (ii) Algae and fungi in a lichen: The fungi protect the algae and also help in the absorption of water while the food manufactured by the algae benefits the fungi as well. (iii) Sea Anemone and hermit crab: The sea anemone eats the leftover food from the hermit crab. In return, the sea anemone protects the hermit crab from predators.

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Testing each possible father genotype against the mother (BO) to see which can produce an O-blood-type child: If the father is BO: BO x BO gives BB, BO, BO, OO offspring (includes OO). If the father is AO: AO x BO gives AB, AO, BO, OO offspring (includes OO). If the father is OO: OO x BO gives BO, OO, BO, OO offspring (includes OO). Since all of BO, AO and OO can father a child of blood type O with a mother of blood type B (BO), the likely blood types of the father are BO, AO and OO.

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Forms of adaptive communication in animals include display, visual communication, auditory communication and chemical communication (any two).

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The reasons for communication among organisms include reproduction and danger alertness.

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The substance to be perceived dissolves in the moist membrane in the nostril and then stimulates the sensory nerve endings which unite to form the olfactory nerve that passes to the brain. When the impulse reaches the brain, the type of smell is interpreted.

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The shell of the egg protects it externally; The airspace enhances respiration; The albumen and the yolk nourish the embryo; The chalaza holds the yolk and the embryo in position within the albumen.

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Autotrophs are organisms that are able to manufacture their own food.

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Euglena and Chlamydomonas are examples of unicellular organisms that exhibit autotrophy.

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WHO provides vaccines and drugs in emergency cases; It prevents the spread of diseases; It educates the public about diseases; It assists poor countries with their medical needs; It helps in the training of medical personnel.

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Duck weed, water lily and water fern are examples of plants that live in a freshwater pond. Mosquito larva and water bugs are examples of animals that live in a freshwater pond.

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Mammalian Skin vs Epidermis of a leaf: It has blood vessels / It lacks blood vessels. It has sweat pores / It lacks sweat pores. It synthesizes vitamin D / It doesn't synthesize vitamin D. It lacks cuticle / It has cuticle. It lacks stomata / It has stomata.

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(i) The type of competition that would be observed on plot A would be intraspecific competition, since the plants on plot A are of the same species. (ii) The type of competition that would be observed on plot B is interspecific competition, since plot B has plants of different species.