Photo AI
Figure 24 shows the world human population from 1800 to 2015 - Edexcel - GCSE Biology - Question 10 - 2020 - Paper 1
Question 10
Figure 24 shows the world human population from 1800 to 2015. (a) In 2015, 13% of the world human population were classified as malnourished. Calculate, using Figur... show full transcript
Worked Solution & Example Answer:Figure 24 shows the world human population from 1800 to 2015 - Edexcel - GCSE Biology - Question 10 - 2020 - Paper 1
Step 1
In 2015, 13% of the world human population were classified as malnourished. Calculate, using Figure 24, how many people were classified as malnourished in 2015.
Answer
To find the number of malnourished people in 2015, first determine the world population from Figure 24, which is approximately 7 billion. Then, calculate 13% of this population:
Thus, approximately 0.91 billion people were classified as malnourished.
Step 2
Describe the laboratory test for protein.
Answer
A common laboratory test for detecting protein is the Biuret test. This involves:
- Adding Biuret reagent, which contains sodium hydroxide and copper (II) sulfate, to the sample.
- Observing any color change; a positive test results in a color change from blue to mauve or purple, indicating the presence of proteins.
Step 3
Calculate the rate of increase in the mass of meat eaten in the world from 2000 to 2010.
Answer
From Figure 25, the mass of meat eaten in 2000 is approximately 175 million tonnes, and in 2010, it is around 250 million tonnes. The increase is calculated as follows:
To find the rate of increase per year:
ext{Rate} = rac{75}{10} = 7.5 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 that labelled plants because of the energy transfer in an ecosystem. Cattle, being at a higher trophic level, receive less energy from the plants they consume due to the 10% energy transfer rule. This results in a smaller biomass of cattle compared to the larger biomass of plants.
Step 5
Explain how a large increase in the mass of meat eaten will decrease food security in the future.
Answer
A large increase in the mass of meat eaten can decrease food security due to several factors:
- Increased demand for livestock can lead to deforestation and loss of arable land, reducing the overall food production capacity.
- Higher meat consumption often demands more grains for feed, putting pressure on food supply.
- Livestock farming can have a substantial environmental impact, contributing to climate change, which threatens future food security. Therefore, while meat is a valuable nutrient source, unsustainable increases can have far-reaching consequences on overall food availability.