Pearson Edexcel · GCSE · Biology
Course version: 1BI0 · Version from Sept 2016
Explain selective breeding and its impact on food plants and domesticated…
Full specification wording
Topic 4 – Natural selection and genetic modification: 4.8 Explain selective breeding and its impact on food plants and domesticated animals
Selective breeding is the deliberate choice of parents with desired characteristics so that those features become more common in later generations.
Checked against the Pearson Edexcel 1BI0 specification (opens in a new tab) on .
- Point 6 of 9
Study notes
From the checked teaching notes for this specification point.
The idea
Selective breeding is the deliberate choice of parents with desired characteristics so that those features become more common in later generations. Breeders identify individuals showing the wanted trait, for example high yield in a wheat variety or docile temperament in cattle, and allow only those to reproduce. Offspring vary, so the best are selected again and the cycle repeats over many generations, gradually shifting the population. The impact on food plants includes higher yields, improved disease resistance and better nutritional quality, while domesticated animals may be bred for more meat or milk, or for temperament. Learners must also recognise drawbacks: reduced genetic variation, increased vulnerability to a single disease, and possible inherited health problems.
What earns the marks
- Selective breeding means choosing parents that show a desired characteristic so offspring inherit it.
- Only selected individuals are allowed to reproduce, and the process is repeated over successive generations.
- In food plants this can raise yield, improve disease resistance or enhance nutritional value.
- In domesticated animals it can increase meat or milk production or produce a desired temperament.
- A key drawback is reduced genetic variation, making a population more vulnerable to disease or environmental change.
- Inherited health or welfare problems can arise when breeding is too narrow.
Common mistakes and how to put them right
Thinking selective breeding creates new genes.
Put it right by explaining that it changes the frequency of existing alleles by choosing which individuals reproduce.
Confusing selective breeding with genetic modification.
Put it right by noting that selective breeding works within existing variation and does not insert genes from another species.
Assuming selective breeding has only benefits.
Put it right by naming reduced genetic variation and increased disease vulnerability as consequences.
Exam tips
- Read the question stem to see whether it asks for a benefit, a drawback or the process itself before choosing.
- Eliminate options that describe inserting genes, since that is genetic modification, not selective breeding.
- Check that the chosen option names a characteristic passed from parents to offspring, not a change acquired during life.
Try the lesson
The start of the Topic 4 – Natural selection and genetic modification: 4.8 Explain selective breeding and its impact on food plants and domesticated animals lesson, made from checked teaching notes for this specification point.
Have a go first
A farmer wants to produce a herd of cattle that give more milk. Which action is the first step in selective breeding for this aim?
Watch it explained
What is the one idea the video explains? Say it in a sentence.
Read the described scene instead
Selective breeding is the deliberate choice of parents that show a desired characteristic, so that those features become more common in later generations. Breeders pick individuals showing the wanted trait and allow only those to reproduce. This is not genetic modification: no genes are inserted from another species. Nothing new is created — what changes is how often existing alleles appear. The process then repeats. Offspring vary, so the best of them are selected again and bred, generation after generation. Each round gradually shifts the population towards the wanted feature. Because selection works on the variation already present, the change is slow and cumulative rather than instant. Here is how it looks in practice. A farmer wants a wheat variety with a high yield. She identifies the plants producing the most grain and saves seed from only those. She grows them, then again selects the highest-yielding offspring. After many cycles, yield across the crop is higher. The same logic gives cattle bred for more milk or a docile temperament. Pause here and think: why must the selection be repeated? In food plants, selective breeding can raise yield, improve disease resistance and enhance nutritional value. In domesticated animals it can increase meat or milk production, or produce a desired temperament. There are real drawbacks. Selecting a narrow group of parents reduces genetic variation in the population. A uniform population is more vulnerable to a single disease or to environmental change, and inherited health or welfare problems can arise when breeding is too narrow. Two common mistakes to avoid: selective breeding does not create new genes, and it is not the same as genetic modification, which inserts genes from another species. To sum up: choose parents with the desired characteristic, breed only those, and repeat over many generations. That can improve yield, quality and temperament — but it narrows genetic variation and can leave a population vulnerable.
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