2016/2017 WAEC BIOLOGY ESSAY AND OBJ ANSWERS

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BIOLOGY OBJ ANS 1-10: dcdacaccdc 11-20: ccbdadbbcd 21-30: dcbdddbacb 31-40: cdabbbbddb 41-50: dbcaabadbc
(1) a i i- free living ii - As filament iii - As colony ======= 1ai) i- free living ii - As filament iii - As colony 1aii) i- Amoeba ii - spirogyre iii -volvox 1b.) Diagram 1c i) Plant cells * has chloroplast * has a large vacoule *has a cell centrioles * has definities shape Animal cell * has no cloroplast * has a small vacoule *has centrioles * has no definite shape
3ai) A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant, or other type of organism. The term typically refers to the zone in which the organism lives and where it can find food, shelter, protection and mates for reproduction, utilizing the qualities the species has adapted to survive within the ecology of the habitat. It is the natural environment in which an organism lives, or the physical environment that surrounds a species population. A habitat is made up of physical factors such as soil, moisture, range of temperature, and availability of light as well as biotic factors such as the availability of food and the presence of predators. A habitat is not necessarily a geographic area—for a parasitic organism it is the body of its host, part of the host's body such as the digestive tract, or a cell within the host's body. =========OR=========== (3ai) A habitat comprises of an organism immediate environment or where it lives or resides (3aii) -They help in the decay of the organisms -They also help to return certain substances like gases eg Nitrogen to the atmosphere thereby regulating certain biological processes such as the Nitrogen cycle,carbon cycle -Some of the substances released are important in processes such as respiration,photosynthesis (3b) Energy flows basically from the producers in a fresh water habitat to the consumers.The producers usually are phytoplanktons which are taken up by the primary consumers usually small fishes. The primary consumer are taken up by the secondary consumers which are larger fishes such as sharks.This sharks may inturn be taken up by man which is the tertiary consumer SCHEMATIC DIAGRAM Phytoplanktons->Small fishes->Sharks->Man (3c) -They causes diseases such as rice smut,black pod of cocoa which may lead to waste -They also reduce the economic value of plants leading to financial loss (3cii) -They help in fermentation of certain substances like yughourt eg lactobacillus species -They help in decomposition and decay of substances eg sprophytic micro organism -They causes diseases eg smallpox and chicken pox hence have been useful tools in the development of antibiotics and vaccines -They are useful in certain biological processes eg photosynthesis -They are used in sewage treatment -Sources of enzymes (2a) Mouth,Oesophagus,Stomach,Duodenum,Small intestine,Caecum,Appendix,Large intestine,Rectum,Anus (2bi) TABULATE Alimentary canal of birds|Alimentary canal of man -There is presence of crop|Crop absent -There is presence of proventiculus|Proventiculus absent -There is presence of gizzard|Gizzard is absent (2bii) -Both have caecum -Both have Oesophagus -Both have duodenum (2c) Herbivore posses heterodant type of dentition in which they posses teeth of different shapes and sizes.Herbivores feed mainly on vegetable hence its teeth is 28 in numbers.Its incisors are flat with sharp cutting edges for cutting vegetables or grasses .canine is absent.the space creates due to absense of the canine is called diastema. Diastema allows manipulation of grasses in the mouth.It has a very large molar and premolar closely packed and have very large ridged surface area for cutting and grinding (2d) -They help in regulation of blood sugar by producing insuling and glucagon -They help in digestion =6a) -Tactic movement movement is found in some plant and animals while nastic movement is found in plants alone -Tactic movement rsponse to directional stimuli while nastic movement respond to non directional stimuli 6bi) -Euglena -Chlamydomonas 6bii) -Mimosa plant -Sunflower 6ci) -Regular cleaning -Exposure to fresh air -Eating balanced diet -Regular exercise 6cii) -Temperature -pressure -Pain -Cold 6d) -High temperature affect evaporation and reduces performance -High temperature may lead to seed dormancy -It leads to loss of soil nutrients through evaporation -It affects the ripening and maturity of plant -it is necessary for germination of seeds 6ei) Courtship behaviour refers to the instructive behaviour on response to certain external stimuli in animals.It is the pattern of behaviour that preceeds mating and reproduction in animals.It is performed by male and female organism 6eii) -pairing -Teritoriality -Display 6f) -Holozoic nutrition -Amoeba -Entamoeba histolytica -Humans 6g) Crime detection using finger print method: this applies to forensic.In this method,individuals having different finger print pattern can be identified using database of stored information of such individuals.These method correctly identifies such individuals aptly and is useful in crime detection ============= 9) i) Single independent free living organism. Eg. Amoeba ii) As a colony. Eg. Volvox iii) As a filament. Eg. Spirogyra i) Amoeba ii) Volvox iii) Spirogyra C)Plant cell i) They are rectangular in shape ii) They contain chloroplast iii) The contain cell wall iv) The nucleus is at the side Animal Cell i) They are spherical in shape ii) They do not contain chloroplast iii) They do not contain cell wall iv) The nucleus is in the middle II) i) They both contain nucleus ii) They both have mitochondria iii) They both have endoplasmic reticulum