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Figure 7 shows the world human population from 1800 to 2015 - Edexcel - GCSE Biology - Question 4 - 2020 - Paper 1
Question 4
Figure 7 shows the world human population from 1800 to 2015. (a) In 2015, 13% of the world human population were classified as malnourished. Calculate, using Figure... show full transcript
Worked Solution & Example Answer:Figure 7 shows the world human population from 1800 to 2015 - Edexcel - GCSE Biology - Question 4 - 2020 - Paper 1
Step 1
Calculate, using Figure 7, how many people were classified as malnourished.
Answer
To find the number of people classified as malnourished, first, we need to determine the world population in 2015 from Figure 7. The graph indicates that the world population in 2015 was approximately 7 billion.
Next, we calculate 13% of this population:
Thus, in 2015, approximately 0.91 billion people were classified as malnourished.
Step 2
Describe the laboratory test for protein.
Answer
To test for protein, the Biuret test can be used. This involves the following steps:
- Add a few drops of Biuret reagent (which contains sodium hydroxide and copper sulfate) to the sample in a test tube.
- If protein is present, the solution will change color from blue to mauve/purple, indicating a positive result.
Step 3
Calculate the rate of increase in the mass of meat eaten in the world from 2000 to 2010.
Answer
From Figure 8, the mass of meat eaten in 2000 was approximately 225 million tonnes, and in 2010 it was approximately 275 million tonnes. The increase in mass from 2000 to 2010 is:
To find the rate of increase per year, divide the total increase by the number of years (10):
rac{50 ext{ million tonnes}}{10 ext{ years}} = 5 ext{ million tonnes per year}
Step 4
Explain why the area labelled cattle is smaller than the area labelled plants.
Answer
The area labelled 'cattle' is smaller than the area labelled 'plants' due to energy loss within the food chain.
- Cattle are primary consumers, and only a fraction of the energy from plants is passed on to them.
- Not all plant material is digestible for cattle; some is excreted or not consumed.
- Additionally, some energy is used for respiration and other metabolic processes, further reducing the amount of energy available for growth.
Step 5
Explain how a large increase in the mass of meat eaten will decrease food security in the future.
Answer
A significant increase in the mass of meat consumed can negatively impact food security in several ways:
- There will be less food available for people to eat since a large portion of crops grown is used for feeding livestock rather than humans.
- Farming for meat production does not provide as much food per acre compared to crop farming, leading to inefficiencies in food production.
- More land will be required for animal farming, reducing the area available for growing human food crops, which can lead to food shortages.