SPM Biology 2011


9 . (a) Diagram 9.1 shows the effects of farming activities near a pond. Explain how the farming activities cause the death of the aquatic plants and the fishes in the pond.

Rajah 9.1 menunjukkan kesan-kesan aktiviti pertanian berhampiran sebuah kolam. Terangkan bagaimana aktiviti-aktiviti pertanian tersebut menyebabkan kematian tumbuhan akuatik dan ikan-ikan di dalam kolam itu.

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(b) Diagram 9.2 shows a new industrial area situated near a residential area. Discuss the good and the bad effects caused by the industrial activities on human and environment in years to come.

Rajah 9.2 menunjukkan satu Kawasan perindustrian baru berdekatan dengan Kawasan perumahan. Bincangkan kesan baik dan kesan buruk yang disebabkan oleh aktiviti-aktiviti perindustrian terhadap manusia dan alam sekitar pada tahun-tahun akan datang.

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Answer ( 1 )


    9.  a)

    -Farming uses fertilizer which contains nitrates and phosphates.

    -Draining these nutrients into the pond promotes the growth of photosynthesizing algae, result in algal bloom.

    -Algae bloom acts like a blanket covering up the entire surface of the pond. Difficult for sunlight to penetrate.

    -Photosynthesis of aquatic plants is inhibited, oxygen concentration in water continues to decrease. Aquatic plants begin to die off due to the lack of sunlight.

    -Algae outgrows the consumers, algae doesn’t get consumed, dies and accumulates as organic matter at the bottom of the lake.

    -This attracts decomposing microorganisms like aerobic bacteria. Excessive growth of the bacteria reduces oxygen supply at a rapid rate. This increases the biochemical oxygen demand (B.O.D) and the concentration of oxygen continues to decrease as it cannot be replenished quickly enough.

    -Low oxygen concentration causes death of aquatic organisms (fishes).



    Good effects:

    -Industries are important for the manufacturing and production of materials.

    -Help to boost our country’s economy.

    Bad effects:

    -Industrial activities causes air pollution.

    -Industries release sulphur dioxide (SO2) and oxides of nitrogen (NO and NO2) into the atmosphere through the combustion of fossil fuels.

    -SO2 and oxides of nitrogen combines with water vapour in the air, forming sulphuric acid and nitric acid.

    -This causes the occurrence of acid rain.

    -Acid rain corrodes metal structures and bridges. Structures made out of limestone/marble will get eroded.

    -Acid rain causes water pollution, contaminates drinking water. Acidity of soil and water increases, causing death of plants and aquatic organisms.

    -Incomplete combustion of fossil fuels in factories also release carbon monoxide, soot and smoke.

    -Carbon monoxide affects the delivery of oxygen to body cells, soot and smoke may irritate the eyes and lungs, causes difficulty in breathing.

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