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Since 2003, in France, people have been buying Siberian chipmunks as pets but then releasing them into the wild when they are no longer wanted - Edexcel - GCSE Biology - Question 10 - 2018 - Paper 1
Question 10
Since 2003, in France, people have been buying Siberian chipmunks as pets but then releasing them into the wild when they are no longer wanted. They are now classif... show full transcript
Worked Solution & Example Answer:Since 2003, in France, people have been buying Siberian chipmunks as pets but then releasing them into the wild when they are no longer wanted - Edexcel - GCSE Biology - Question 10 - 2018 - Paper 1
Step 1
(i) Draw a pyramid of biomass for this food chain.
Answer
To draw a pyramid of biomass, create a vertical representation where each bar corresponds to one organism with its biomass. In this case:
- The base of the pyramid (largest) represents acorns with a biomass of 20,650 kg.
- The second bar should represent Siberian chipmunks with a biomass of 2,200 kg, which is less than 50% of acorns.
- The top bar represents wild dogs with a biomass of 230 kg, which is equal to or less than 50% of the chipmunks. Ensure all bars are proportional in height.
The shape should form a pyramid.
Step 2
(ii) Describe how this affected the Siberian chipmunk population in France.
Answer
In France, the lack of natural predators for Siberian chipmunks allows their population to grow rapidly. With fewer chipmunks facing predation, their numbers can increase significantly. Consequently, this leads to more chipmunks being able to reproduce, further expanding their population in the wild.
Step 3
(iii) Calculate the amount of energy transferred to the chipmunks.
Answer
To calculate the energy transferred to the chipmunks, use the formula:
Energy transferred = Total energy in acorns × Percentage of energy transferred
= 97,500 kJ × 0.095 = 9,262.5 kJ
Rounding to the nearest whole number, the energy transferred to the chipmunks is approximately 9,263 kJ.
Step 4
(i) Calculate the percentage increase in the number of cases of Lyme disease in humans in France from 2003 to 2015.
Answer
To calculate the percentage increase, first find the number of cases in 2015 and 2003:
- Cases in 2003: 9,500
- Cases in 2015: 27,000
Percentage Increase = ((27,000 - 9,500) / 9,500) × 100
= (17,500 / 9,500) × 100
≈ 184.21%.
Thus, the percentage increase is approximately 184.21%.
Step 5
(ii) Explain why there has been an increase in the number of cases of Lyme disease in humans in France.
Answer
The increase in Lyme disease cases can be attributed to several factors:
- The growing population of Siberian chipmunks, which serve as hosts for ticks.
- An increase in tick populations due to more food sources (i.e., chipmunks).
- Environmental changes that extend the habitat areas for ticks and their hosts, leading to more encounters between ticks and humans.