Farmers selectively breed chickens to produce larger chickens - Edexcel - GCSE Biology Combined Science - Question 3 - 2020 - Paper 1
Question 3
Farmers selectively breed chickens to produce larger chickens.
Figure 4 shows how the size of chickens has changed over time.
Worked Solution & Example Answer:Farmers selectively breed chickens to produce larger chickens - Edexcel - GCSE Biology Combined Science - Question 3 - 2020 - Paper 1
Step 1
Select large chickens / chicks from larger chickens
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To begin the selective breeding process, farmers must first identify and select larger chickens or chicks that exhibit desirable traits.
Step 2
Breed together
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Once the large chickens are selected, they should be mated together to ensure that the offspring will inherit these desirable characteristics.
Step 3
Repeat over (many) generations / long period of time
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This process of selection and breeding needs to be conducted over multiple generations to reinforce and stabilize the trait of larger size in the chicken population.
Step 4
Benefit
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One benefit of this selective breeding process is that it produces more food, as fewer chickens are required to produce the same amount of meat, resulting in more efficient farming.
Step 5
Risk
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However, a significant risk is that there will be less genetic variation, which can lead to the loss of useful genes from the gene pool. This could result in losing desirable traits in the future and may also pose health issues related to larger body sizes.
Step 6
39 / thirty-nine
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The answer to this part of the question is 39, which can also be referred to as 'thirty-nine' in written form.
Step 7
Meiosis / meiotic cell division
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Lastly, it is important to note that the process being referred to here is meiosis, also known as meiotic cell division, which is essential for producing gametes.
