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The table below gives information about the sources of marine pollution - NSC Life Sciences - Question 3 - 2018 - Paper 1
Question 3
The table below gives information about the sources of marine pollution. | SOURCES OF MARINE POLLUTION | PERCENTAGE CONTRIBUTION TO POLLUTION | |-------------------... show full transcript
Worked Solution & Example Answer:The table below gives information about the sources of marine pollution - NSC Life Sciences - Question 3 - 2018 - Paper 1
Step 1
Draw a bar graph to represent the percentage contribution of sewage, farm runoff, industrial waste and organic litter to marine pollution.
Answer
To draw the bar graph:
- Title the graph: 'Percentage Contribution of Marine Pollution Sources'.
- Label the X-axis and Y-axis: The X-axis will represent 'Source of Marine Pollution' and the Y-axis will be 'Percentage Contribution to Pollution (%)'.
- Choose a suitable scale: The Y-axis should be divided into intervals that can effectively display values from 0 to 35, such as increments of 5.
- Plot the bars:
- Sewage: 30%
- Farm Runoff: 20%
- Industrial Waste: 10%
- Organic Litter: 5%
- Ensure proper spacing between the bars for clear visibility and aesthetic appeal.
- Add colors to the bars for better differentiation and include a legend if necessary. Ensure that each element is accurately labeled and the bars are plotted according to their respective values.
Step 2
Describe how this pollution reduces oxygen levels in the water.
Answer
Untreated sewage and organic litter introduce nutrients into the water, leading to a process known as eutrophication. The following steps outline how this process reduces oxygen levels:
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Nutrient Increase: The sewage and litter provide nutrients that lead to algal blooms, which significantly increase the biomass in the water.
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Algal Bloom Effect: As algae proliferate, they cover the water's surface, blocking sunlight necessary for aquatic plants.
- This deprives these plants of light, hindering their ability to perform photosynthesis, which produces oxygen.
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Decomposition: When algal blooms eventually die, they are decomposed by bacteria. This decomposition process consumes dissolved oxygen in the water, leading to hypoxic conditions.
- A reduction in oxygen levels affects fish and other aquatic organisms, potentially leading to their death.
Step 3
Describe the role of the endocrine system in managing blood glucose levels.
Answer
The endocrine system plays a crucial role in maintaining homeostasis of blood glucose levels, particularly in response to sugar intake. The following summary elucidates this mechanism:
- Rise in Blood Glucose: Upon consuming a large amount of sugar, blood glucose levels rise above normal.
- Insulin Secretion: The pancreas responds by secreting insulin, a hormone produced by the islets of Langerhans.
- Cellular Uptake: Insulin facilitates the uptake of glucose by cells, particularly in the liver and muscle tissues, where it can be stored as glycogen.
- Liver Function: The liver plays a critical role in managing excess glucose, converting it into glycogen for storage, effectively lowering blood glucose levels back to normal.
- Negative Feedback Loop: As glucose levels decrease, the secretion of insulin is reduced, maintaining homeostasis.